draft-ietf-taps-interface-15.txt   draft-ietf-taps-interface-16.txt 
TAPS Working Group B. Trammell, Ed. TAPS Working Group B. Trammell, Ed.
Internet-Draft Google Switzerland GmbH Internet-Draft Google Switzerland GmbH
Intended status: Standards Track M. Welzl, Ed. Intended status: Standards Track M. Welzl, Ed.
Expires: 8 September 2022 University of Oslo Expires: 5 March 2023 University of Oslo
T. Enghardt T. Enghardt
Netflix Netflix
G. Fairhurst G. Fairhurst
University of Aberdeen University of Aberdeen
M. Kuehlewind M. Kuehlewind
Ericsson Ericsson
C. Perkins C. Perkins
University of Glasgow University of Glasgow
P. Tiesel P. Tiesel
SAP SE SAP SE
T. Pauly T. Pauly
Apple Inc. Apple Inc.
7 March 2022 1 September 2022
An Abstract Application Layer Interface to Transport Services An Abstract Application Layer Interface to Transport Services
draft-ietf-taps-interface-15 draft-ietf-taps-interface-16
Abstract Abstract
This document describes an abstract application programming This document describes an abstract application programming
interface, API, to the transport layer that enables the selection of interface, API, to the transport layer that enables the selection of
transport protocols and network paths dynamically at runtime. This transport protocols and network paths dynamically at runtime. This
API enables faster deployment of new protocols and protocol features API enables faster deployment of new protocols and protocol features
without requiring changes to the applications. The specified API without requiring changes to the applications. The specified API
follows the Transport Services architecture by providing follows the Transport Services architecture by providing
asynchronous, atomic transmission of messages. It is intended to asynchronous, atomic transmission of messages. It is intended to
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on 8 September 2022. This Internet-Draft will expire on 5 March 2023.
Copyright Notice Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/ Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document. license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
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8. Managing Connections . . . . . . . . . . . . . . . . . . . . 44 8. Managing Connections . . . . . . . . . . . . . . . . . . . . 44
8.1. Generic Connection Properties . . . . . . . . . . . . . . 46 8.1. Generic Connection Properties . . . . . . . . . . . . . . 46
8.1.1. Required Minimum Corruption Protection Coverage for 8.1.1. Required Minimum Corruption Protection Coverage for
Receiving . . . . . . . . . . . . . . . . . . . . . . 46 Receiving . . . . . . . . . . . . . . . . . . . . . . 46
8.1.2. Connection Priority . . . . . . . . . . . . . . . . . 47 8.1.2. Connection Priority . . . . . . . . . . . . . . . . . 47
8.1.3. Timeout for Aborting Connection . . . . . . . . . . . 47 8.1.3. Timeout for Aborting Connection . . . . . . . . . . . 47
8.1.4. Timeout for keep alive packets . . . . . . . . . . . 47 8.1.4. Timeout for keep alive packets . . . . . . . . . . . 47
8.1.5. Connection Group Transmission Scheduler . . . . . . . 48 8.1.5. Connection Group Transmission Scheduler . . . . . . . 48
8.1.6. Capacity Profile . . . . . . . . . . . . . . . . . . 48 8.1.6. Capacity Profile . . . . . . . . . . . . . . . . . . 48
8.1.7. Policy for using Multipath Transports . . . . . . . . 50 8.1.7. Policy for using Multipath Transports . . . . . . . . 50
8.1.8. Bounds on Send or Receive Rate . . . . . . . . . . . 51 8.1.8. Bounds on Send or Receive Rate . . . . . . . . . . . 50
8.1.9. Group Connection Limit . . . . . . . . . . . . . . . 51 8.1.9. Group Connection Limit . . . . . . . . . . . . . . . 51
8.1.10. Isolate Session . . . . . . . . . . . . . . . . . . . 51 8.1.10. Isolate Session . . . . . . . . . . . . . . . . . . . 51
8.1.11. Read-only Connection Properties . . . . . . . . . . . 52 8.1.11. Read-only Connection Properties . . . . . . . . . . . 52
8.2. TCP-specific Properties: User Timeout Option (UTO) . . . 53 8.2. TCP-specific Properties: User Timeout Option (UTO) . . . 53
8.2.1. Advertised User Timeout . . . . . . . . . . . . . . . 53 8.2.1. Advertised User Timeout . . . . . . . . . . . . . . . 53
8.2.2. User Timeout Enabled . . . . . . . . . . . . . . . . 53 8.2.2. User Timeout Enabled . . . . . . . . . . . . . . . . 53
8.2.3. Timeout Changeable . . . . . . . . . . . . . . . . . 54 8.2.3. Timeout Changeable . . . . . . . . . . . . . . . . . 54
8.3. Connection Lifecycle Events . . . . . . . . . . . . . . . 54 8.3. Connection Lifecycle Events . . . . . . . . . . . . . . . 54
8.3.1. Soft Errors . . . . . . . . . . . . . . . . . . . . . 54 8.3.1. Soft Errors . . . . . . . . . . . . . . . . . . . . . 54
8.3.2. Path change . . . . . . . . . . . . . . . . . . . . . 54 8.3.2. Path change . . . . . . . . . . . . . . . . . . . . . 54
9. Data Transfer . . . . . . . . . . . . . . . . . . . . . . . . 54 9. Data Transfer . . . . . . . . . . . . . . . . . . . . . . . . 54
9.1. Messages and Framers . . . . . . . . . . . . . . . . . . 55 9.1. Messages and Framers . . . . . . . . . . . . . . . . . . 55
9.1.1. Message Contexts . . . . . . . . . . . . . . . . . . 55 9.1.1. Message Contexts . . . . . . . . . . . . . . . . . . 55
9.1.2. Message Framers . . . . . . . . . . . . . . . . . . . 55 9.1.2. Message Framers . . . . . . . . . . . . . . . . . . . 55
9.1.3. Message Properties . . . . . . . . . . . . . . . . . 58 9.1.3. Message Properties . . . . . . . . . . . . . . . . . 58
9.2. Sending Data . . . . . . . . . . . . . . . . . . . . . . 64 9.2. Sending Data . . . . . . . . . . . . . . . . . . . . . . 64
9.2.1. Basic Sending . . . . . . . . . . . . . . . . . . . . 64 9.2.1. Basic Sending . . . . . . . . . . . . . . . . . . . . 64
9.2.2. Send Events . . . . . . . . . . . . . . . . . . . . . 65 9.2.2. Send Events . . . . . . . . . . . . . . . . . . . . . 65
9.2.3. Partial Sends . . . . . . . . . . . . . . . . . . . . 66 9.2.3. Partial Sends . . . . . . . . . . . . . . . . . . . . 66
9.2.4. Batching Sends . . . . . . . . . . . . . . . . . . . 66 9.2.4. Batching Sends . . . . . . . . . . . . . . . . . . . 67
9.2.5. Send on Active Open: InitiateWithSend . . . . . . . . 67 9.2.5. Send on Active Open: InitiateWithSend . . . . . . . . 67
9.2.6. Priority and the Transport Services API . . . . . . . 67 9.2.6. Priority and the Transport Services API . . . . . . . 68
9.3. Receiving Data . . . . . . . . . . . . . . . . . . . . . 68 9.3. Receiving Data . . . . . . . . . . . . . . . . . . . . . 68
9.3.1. Enqueuing Receives . . . . . . . . . . . . . . . . . 68 9.3.1. Enqueuing Receives . . . . . . . . . . . . . . . . . 69
9.3.2. Receive Events . . . . . . . . . . . . . . . . . . . 69 9.3.2. Receive Events . . . . . . . . . . . . . . . . . . . 69
9.3.3. Receive Message Properties . . . . . . . . . . . . . 71 9.3.3. Receive Message Properties . . . . . . . . . . . . . 72
10. Connection Termination . . . . . . . . . . . . . . . . . . . 73 10. Connection Termination . . . . . . . . . . . . . . . . . . . 73
11. Connection State and Ordering of Operations and Events . . . 74 11. Connection State and Ordering of Operations and Events . . . 75
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 76 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 76
13. Privacy and Security Considerations . . . . . . . . . . . . . 76 13. Privacy and Security Considerations . . . . . . . . . . . . . 76
14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 78 14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 78
15. References . . . . . . . . . . . . . . . . . . . . . . . . . 78 15. References . . . . . . . . . . . . . . . . . . . . . . . . . 78
15.1. Normative References . . . . . . . . . . . . . . . . . . 78 15.1. Normative References . . . . . . . . . . . . . . . . . . 78
15.2. Informative References . . . . . . . . . . . . . . . . . 79 15.2. Informative References . . . . . . . . . . . . . . . . . 79
Appendix A. Implementation Mapping . . . . . . . . . . . . . . . 83 Appendix A. Implementation Mapping . . . . . . . . . . . . . . . 83
A.1. Types . . . . . . . . . . . . . . . . . . . . . . . . . . 83 A.1. Types . . . . . . . . . . . . . . . . . . . . . . . . . . 83
A.2. Events and Errors . . . . . . . . . . . . . . . . . . . . 84 A.2. Events and Errors . . . . . . . . . . . . . . . . . . . . 84
A.3. Time Duration . . . . . . . . . . . . . . . . . . . . . . 84 A.3. Time Duration . . . . . . . . . . . . . . . . . . . . . . 84
Appendix B. Convenience Functions . . . . . . . . . . . . . . . 84 Appendix B. Convenience Functions . . . . . . . . . . . . . . . 84
B.1. Adding Preference Properties . . . . . . . . . . . . . . 84 B.1. Adding Preference Properties . . . . . . . . . . . . . . 84
B.2. Transport Property Profiles . . . . . . . . . . . . . . . 84 B.2. Transport Property Profiles . . . . . . . . . . . . . . . 84
B.2.1. reliable-inorder-stream . . . . . . . . . . . . . . . 84 B.2.1. reliable-inorder-stream . . . . . . . . . . . . . . . 85
B.2.2. reliable-message . . . . . . . . . . . . . . . . . . 85 B.2.2. reliable-message . . . . . . . . . . . . . . . . . . 85
B.2.3. unreliable-datagram . . . . . . . . . . . . . . . . . 85 B.2.3. unreliable-datagram . . . . . . . . . . . . . . . . . 85
Appendix C. Relationship to the Minimal Set of Transport Services Appendix C. Relationship to the Minimal Set of Transport Services
for End Systems . . . . . . . . . . . . . . . . . . . . . 86 for End Systems . . . . . . . . . . . . . . . . . . . . . 86
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 89 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 89
1. Introduction 1. Introduction
This document specifies an abstract application programming interface This document specifies an abstract application programming interface
(API) that specifies the interface component of the high-level (API) that specifies the interface component of the high-level
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with a question mark are optional. with a question mark are optional.
Action(param0, param1?, ...) / Event<param0, param1, ...> Action(param0, param1?, ...) / Event<param0, param1, ...>
Objects that are passed as parameters to Actions use call-by-value Objects that are passed as parameters to Actions use call-by-value
behavior. Actions associated with no Object are Actions on the API; behavior. Actions associated with no Object are Actions on the API;
they are equivalent to Actions on a per-application global context. they are equivalent to Actions on a per-application global context.
Events are sent to the application or application-supplied code (e.g. Events are sent to the application or application-supplied code (e.g.
framers, see Section 9.1.2) for processing; the details of event framers, see Section 9.1.2) for processing; the details of event
processing are platform- and implementation-specific. interfaces are platform- and implementation-specific, and may be
implemented using other forms of asynchronous processing, as
idiomatic for the implementing platform.
We also make use of the following basic types: We also make use of the following basic types:
* Boolean: Instances take the value true or false. * Boolean: Instances take the value true or false.
* Integer: Instances take positive or negative integer values. * Integer: Instances take positive or negative integer values.
* Numeric: Instances take positive or negative real number values. * Numeric: Instances take positive or negative real number values.
* Enumeration: A family of types in which each instance takes one of * Enumeration: A family of types in which each instance takes one of
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* Transport Services systems SHOULD implement each Selection * Transport Services systems SHOULD implement each Selection
Property, Connection Property, and Message Context Property Property, Connection Property, and Message Context Property
specified in this document. The Transport Services API SHOULD be specified in this document. The Transport Services API SHOULD be
implemented even when in a specific implementation/platform it implemented even when in a specific implementation/platform it
will always result in no operation, e.g. there is no action when will always result in no operation, e.g. there is no action when
the API specifies a Property that is not available in a transport the API specifies a Property that is not available in a transport
protocol implemented on a specific platform. For example, if TCP protocol implemented on a specific platform. For example, if TCP
is the only underlying transport protocol, the Message Property is the only underlying transport protocol, the Message Property
msgOrdered can be implemented (trivially, as a no-op) as disabling msgOrdered can be implemented (trivially, as a no-op) as disabling
the requirement for ordering will not have any effect on delivery the requirement for ordering will not have any effect on delivery
order for Connections over TCP. Similarly, the msg-lifetime order for Connections over TCP. Similarly, the msgLifetime
Message Property can be implemented but ignored, as the Message Property can be implemented but ignored, as the
description of this Property states that "it is not guaranteed description of this Property states that "it is not guaranteed
that a Message will not be sent when its Lifetime has expired". that a Message will not be sent when its Lifetime has expired".
* Implementations may use other representations for Transport * Implementations may use other representations for Transport
Property Names, e.g., by providing constants, but should provide a Property Names, e.g., by providing constants, but should provide a
straight-forward mapping between their representation and the straight-forward mapping between their representation and the
property names specified here. property names specified here.
6. Pre-Establishment Phase 6. Pre-Establishment Phase
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The protocol(s) and path(s) selected as candidates during The protocol(s) and path(s) selected as candidates during
establishment are determined and configured using these properties. establishment are determined and configured using these properties.
Since there could be paths over which some transport protocols are Since there could be paths over which some transport protocols are
unable to operate, or remote endpoints that support only specific unable to operate, or remote endpoints that support only specific
network addresses or transports, transport protocol selection is network addresses or transports, transport protocol selection is
necessarily tied to path selection. This may involve choosing necessarily tied to path selection. This may involve choosing
between multiple local interfaces that are connected to different between multiple local interfaces that are connected to different
access networks. access networks.
When additional information (such as Provisioning Domain (PvD) When additional information (such as Provisioning Domain (PvD)
information Path information can include network segment PMTU, set of information [RFC7556]) is available about the networks over which an
supported DSCPs, expected usage, cost, etc. The usage of this endpoint can operate, this can inform the selection between alternate
network paths. Path information can include network segment PMTU,
set of supported DSCPs, expected usage, cost, etc. The usage of this
information by the Transport Services System is generally independent information by the Transport Services System is generally independent
of the specific mechanism/protocol used to receive the information of the specific mechanism/protocol used to receive the information
(e.g. zero-conf, DHCP, or IPv6 RA).[RFC7556]) is available about the (e.g. zero-conf, DHCP, or IPv6 RA).
networks over which an endpoint can operate, this can inform the
selection between alternate network paths.
Most Selection Properties are represented as Preferences, which can Most Selection Properties are represented as Preferences, which can
take one of five values: take one of five values:
+============+========================================+ +============+========================================+
| Preference | Effect | | Preference | Effect |
+============+========================================+ +============+========================================+
| Require | Select only protocols/paths providing | | Require | Select only protocols/paths providing |
| | the property, fail otherwise | | | the property, fail otherwise |
+------------+----------------------------------------+ +------------+----------------------------------------+
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Individual properties are then set on the TransportProperties Object. Individual properties are then set on the TransportProperties Object.
Setting a Transport Property to a value overrides the previous value Setting a Transport Property to a value overrides the previous value
of this Transport Property. of this Transport Property.
TransportProperties.Set(property, value) TransportProperties.Set(property, value)
To aid readability, implementations MAY provide additional To aid readability, implementations MAY provide additional
convenience functions to simplify use of Selection Properties: see convenience functions to simplify use of Selection Properties: see
Appendix B.1 for examples. In addition, implementations MAY provide Appendix B.1 for examples. In addition, implementations MAY provide
a mechanism to create TransportProperties objects that are a mechanism to create TransportProperties objects that are
preconfigured for common use cases as outlined in Appendix B.2. preconfigured for common use cases, as outlined in Appendix B.2.
Transport Properties for an established connection can be queried via Transport Properties for an established connection can be queried via
the Connection object, as outlined in Section 8. the Connection object, as outlined in Section 8.
A Connection gets its Transport Properties either by being explicitly A Connection gets its Transport Properties either by being explicitly
configured via a Preconnection, by configuration after establishment, configured via a Preconnection, by configuration after establishment,
or by inheriting them from an antecedent via cloning; see Section 7.4 or by inheriting them from an antecedent via cloning; see Section 7.4
for more. for more.
Section 8.1 provides a list of Connection Properties, while Selection Section 8.1 provides a list of Connection Properties, while Selection
Properties are listed in the subsections below. Many properties are Properties are listed in the subsections below. Selection Properties
only considered during establishment, and can not be changed after a are only considered during establishment, and can not be changed
Connection is established; however, they can still be queried. The after a Connection is established. After a Connection is
return type of a queried Selection Property is Boolean, where true established, Selection Properties can only be read to check the
means that the Selection Property has been applied and false means properties used by the Connection. Upon reading, the Preference type
that the Selection Property has not been applied. Note that true of a Selection Property changes into Boolean, where true means that
does not mean that a request has been honored. For example, if the selected Protocol Stack supports the feature or uses the path
Congestion control was requested with preference level Prefer, but associated with the Selection Property, and false means that the
congestion control could not be supported, querying the Protocol Stack does not support the feature or use the path.
congestionControl property yields the value false. If the preference Implementations of Transport Services systems may alternatively use
level Avoid was used for Congestion control, and, as requested, the the two Preference values Require and Prohibit to represent true and
Connection is not congestion controlled, querying the false, respectively.
congestionControl property also yields the value false.
An implementation of the Transport Services API must provide sensible An implementation of the Transport Services API must provide sensible
defaults for Selection Properties. The default values for each defaults for Selection Properties. The default values for each
property below represent a configuration that can be implemented over property below represent a configuration that can be implemented over
TCP. If these default values are used and TCP is not supported by a TCP. If these default values are used and TCP is not supported by a
Transport Services system, then an application using the default set Transport Services system, then an application using the default set
of Properties might not succeed in establishing a connection. Using of Properties might not succeed in establishing a connection. Using
the same default values for independent Transport Services the same default values for independent Transport Services
implementations can be beneficial when applications are ported implementations can be beneficial when applications are ported
between different implementations/platforms, even if this default between different implementations/platforms, even if this default
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a particular endpoint. Section 6.1.2 provides details about how to a particular endpoint. Section 6.1.2 provides details about how to
qualify endpoint candidates on a per-interface basis. qualify endpoint candidates on a per-interface basis.
6.2.12. Provisioning Domain Instance or Type 6.2.12. Provisioning Domain Instance or Type
Name: pvd Name: pvd
Type: Collection of (Preference, Enumeration) Type: Collection of (Preference, Enumeration)
Default: Empty (not setting a preference for any PvD) Default: Empty (not setting a preference for any PvD)
Similar to interface instances and types (see Section 6.2.11), this Similar to interface (see Section 6.2.11), this property allows the
property allows the application to control path selection by application to control path selection by selecting which specific
selecting which specific Provisioning Domain (PvD) or categories of Provisioning Domain (PvD) or categories of PVDs it wants to Require,
PVDs it wants to Require, Prohibit, Prefer, or Avoid. Provisioning Prohibit, Prefer, or Avoid. Provisioning Domains define consistent
Domains define consistent sets of network properties that may be more sets of network properties that may be more specific than network
specific than network interfaces [RFC7556]. interfaces [RFC7556].
As with interface instances and types, this property is a tuple of an As with interface instances and types, this property is a tuple of an
(Enumerated) PvD identifier and a preference, and can either be (Enumerated) PvD identifier and a preference, and can either be
implemented directly as such, or for making one preference available implemented directly as such, or for making one preference available
for each interface and interface type available on the system. for each interface and interface type available on the system.
The identification of a specific PvD is implementation- and system- The identification of a specific PvD is implementation- and system-
specific, because there is currently no portable standard format for specific, because there is currently no portable standard format for
a PvD identifier. For example, this identifier might be a string a PvD identifier. For example, this identifier might be a string
name or an integer. As with requiring specific interfaces, requiring name or an integer. As with requiring specific interfaces, requiring
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established, even if the chosen transport supports using multiple established, even if the chosen transport supports using multiple
paths. paths.
Active: The connection will negotiate the use of multiple paths if Active: The connection will negotiate the use of multiple paths if
the chosen transport supports this. the chosen transport supports this.
Passive: The connection will support the use of multiple paths if Passive: The connection will support the use of multiple paths if
the Remote Endpoint requests it. the Remote Endpoint requests it.
The policy for using multiple paths is specified using the separate The policy for using multiple paths is specified using the separate
multipath-policy property, see Section 8.1.7 below. To enable the multipathPolicy property, see Section 8.1.7 below. To enable the
peer endpoint to initiate additional paths towards a local address peer endpoint to initiate additional paths towards a local address
other than the one initially used, it is necessary to set the other than the one initially used, it is necessary to set the
Alternative Addresses property (see Section 6.2.15 below). advertisesAltaddr property (see Section 6.2.15 below).
Setting this property to "Active", can have privacy implications: It Setting this property to "Active", can have privacy implications: It
enables the transport to establish connectivity using alternate paths enables the transport to establish connectivity using alternate paths
that might result in users being linkable across the multiple paths, that might result in users being linkable across the multiple paths,
even if the Advertisement of Alternative Addresses property (see even if the advertisesAltaddr property (see Section 6.2.15 below) is
Section 6.2.15 below) is set to false. set to false.
Note that Multipath Transport has no corresponding Selection Property Note that Multipath Transport has no corresponding Selection Property
of type Preference. Enumeration values other than "Disabled" are of type Preference. Enumeration values other than "Disabled" are
interpreted as a preference for choosing protocols that can make use interpreted as a preference for choosing protocols that can make use
of multiple paths. The "Disabled" value implies a requirement not to of multiple paths. The "Disabled" value implies a requirement not to
use multiple paths in parallel but does not prevent choosing a use multiple paths in parallel but does not prevent choosing a
protocol that is capable of using multiple paths, e.g., it does not protocol that is capable of using multiple paths, e.g., it does not
prevent choosing TCP, but prevents sending the MP_CAPABLE option in prevent choosing TCP, but prevents sending the MP_CAPABLE option in
the TCP handshake. the TCP handshake.
6.2.15. Advertisement of Alternative Addresses 6.2.15. Advertisement of Alternative Addresses
Name: advertises-altaddr Name: advertisesAltaddr
Type: Boolean Type: Boolean
Default: False Default: False
This property specifies whether alternative addresses, e.g., of other This property specifies whether alternative addresses, e.g., of other
interfaces, should be advertised to the peer endpoint by the protocol interfaces, should be advertised to the peer endpoint by the protocol
stack. Advertising these addresses enables the peer-endpoint to stack. Advertising these addresses enables the peer-endpoint to
establish additional connectivity, e.g., for connection migration or establish additional connectivity, e.g., for connection migration or
using multiple paths. using multiple paths.
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Name: activeReadBeforeSend Name: activeReadBeforeSend
Type: Preference Type: Preference
Default: Ignore Default: Ignore
The most common client-server communication pattern involves the The most common client-server communication pattern involves the
client actively opening a connection, then sending data to the client actively opening a connection, then sending data to the
server. The server listens (passive open), reads, and then answers. server. The server listens (passive open), reads, and then answers.
This property specifies whether an application wants to diverge from This property specifies whether an application wants to diverge from
this pattern - either by actively opening with Initiate(), this pattern -- either by actively opening with Initiate(),
immediately followed by reading, or passively opening with Listen(), immediately followed by reading, or passively opening with Listen(),
immediately followed by writing. This property is ignored when immediately followed by writing. This property is ignored when
establishing connections using Rendezvous(). Requiring this property establishing connections using Rendezvous(). Requiring this property
limits the choice of mappings to underlying protocols, which can limits the choice of mappings to underlying protocols, which can
reduce efficiency. For example, it prevents the Transport Services reduce efficiency. For example, it prevents the Transport Services
system from mapping Connections to SCTP streams, where the first system from mapping Connections to SCTP streams, where the first
transmitted data takes the role of an active open signal transmitted data takes the role of an active open signal
[I-D.ietf-taps-impl]. [I-D.ietf-taps-impl].
6.3. Specifying Security Parameters and Callbacks 6.3. Specifying Security Parameters and Callbacks
skipping to change at page 36, line 43 skipping to change at page 36, line 43
opportunistic. If security is disabled, the Transport Services opportunistic. If security is disabled, the Transport Services
system will not attempt to add transport security automatically. If system will not attempt to add transport security automatically. If
security is opportunistic, it will allow Connections without security is opportunistic, it will allow Connections without
transport security, but will still attempt to use security if transport security, but will still attempt to use security if
available. available.
SecurityParameters := NewDisabledSecurityParameters() SecurityParameters := NewDisabledSecurityParameters()
SecurityParameters := NewOpportunisticSecurityParameters() SecurityParameters := NewOpportunisticSecurityParameters()
Representation of Security Parameters in implementations should Representation of security parameters in implementations should
parallel that chosen for Transport Property names as sugggested in parallel that chosen for Transport Property names as sugggested in
Section 5. Section 5.
6.3.2. Connection Establishment Callbacks 6.3.2. Connection Establishment Callbacks
Security decisions, especially pertaining to trust, are not static. Security decisions, especially pertaining to trust, are not static.
Once configured, parameters may also be supplied during connection Once configured, parameters may also be supplied during connection
establishment. These are best handled as client-provided callbacks. establishment. These are best handled as client-provided callbacks.
Callbacks block the progress of the connection establishment, which Callbacks block the progress of the connection establishment, which
distinguishes them from other Events in the transport system. How distinguishes them from other Events in the transport system. How
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The Initiate() Action returns a Connection object. Once Initiate() The Initiate() Action returns a Connection object. Once Initiate()
has been called, any changes to the Preconnection MUST NOT have any has been called, any changes to the Preconnection MUST NOT have any
effect on the Connection. However, the Preconnection can be reused, effect on the Connection. However, the Preconnection can be reused,
e.g., to Initiate another Connection. e.g., to Initiate another Connection.
Once Initiate is called, the candidate Protocol Stack(s) may cause Once Initiate is called, the candidate Protocol Stack(s) may cause
one or more candidate transport-layer connections to be created to one or more candidate transport-layer connections to be created to
the specified Remote Endpoint. The caller may immediately begin the specified Remote Endpoint. The caller may immediately begin
sending Messages on the Connection (see Section 9.2) after calling sending Messages on the Connection (see Section 9.2) after calling
Initiate(); note that any data marked Safely Replayable that is sent Initiate(); note that any data marked as "safely replayable" that is
while the Connection is being established may be sent multiple times sent while the Connection is being established may be sent multiple
or on multiple candidates. times or on multiple candidates.
The following Events may be sent by the Connection after Initiate() The following Events may be sent by the Connection after Initiate()
is called: is called:
Connection -> Ready<> Connection -> Ready<>
The Ready Event occurs after Initiate has established a transport- The Ready Event occurs after Initiate has established a transport-
layer connection on at least one usable candidate Protocol Stack over layer connection on at least one usable candidate Protocol Stack over
at least one candidate Path. No Receive Events (see Section 9.3) at least one candidate Path. No Receive Events (see Section 9.3)
will occur before the Ready Event for Connections established using will occur before the Ready Event for Connections established using
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SetNewConnectionLimit(). This mechanism allows a server to protect SetNewConnectionLimit(). This mechanism allows a server to protect
itself from being drained of resources. Each time a new Connection itself from being drained of resources. Each time a new Connection
is delivered by the ConnectionReceived Event, the value is is delivered by the ConnectionReceived Event, the value is
automatically decremented. Once the value reaches zero, no further automatically decremented. Once the value reaches zero, no further
Connections will be delivered until the caller sets the limit to a Connections will be delivered until the caller sets the limit to a
higher value. By default, this value is Infinite. The caller is higher value. By default, this value is Infinite. The caller is
also able to reset the value to Infinite at any point. also able to reset the value to Infinite at any point.
Listener -> EstablishmentError<reason?> Listener -> EstablishmentError<reason?>
An EstablishmentError occurs either when the Properties and Security An EstablishmentError occurs either when the Properties and security
Parameters of the Preconnection cannot be fulfilled for listening or parameters of the Preconnection cannot be fulfilled for listening or
cannot be reconciled with the Local Endpoint (and/or Remote Endpoint, cannot be reconciled with the Local Endpoint (and/or Remote Endpoint,
if specified), when the Local Endpoint (or Remote Endpoint, if if specified), when the Local Endpoint (or Remote Endpoint, if
specified) cannot be resolved, or when the application is prohibited specified) cannot be resolved, or when the application is prohibited
from listening by policy. from listening by policy.
Listener -> Stopped<> Listener -> Stopped<>
A Stopped Event occurs after the Listener has stopped listening. A Stopped Event occurs after the Listener has stopped listening.
7.3. Peer-to-Peer Establishment: Rendezvous 7.3. Peer-to-Peer Establishment: Rendezvous
Simultaneous peer-to-peer Connection establishment is supported by Simultaneous peer-to-peer Connection establishment is supported by
the Rendezvous() Action: the Rendezvous() Action:
Preconnection.Rendezvous() Preconnection.Rendezvous()
A Preconnection Object used in a Rendezvous() MUST have both the A Preconnection Object used in a Rendezvous() MUST have both the
Local Endpoint candidates and the Remote Endpoint candidates Local Endpoint candidates and the Remote Endpoint candidates
specified, along with the transport properties and security specified, along with the Transport Properties and security
parameters needed for Protocol Stack selection, before the parameters needed for Protocol Stack selection, before the
Rendezvous() Action is initiated. Rendezvous() Action is initiated.
The Rendezvous() Action listens on the Local Endpoint candidates for The Rendezvous() Action listens on the Local Endpoint candidates for
an incoming Connection from the Remote Endpoint candidates, while an incoming Connection from the Remote Endpoint candidates, while
also simultaneously trying to establish a Connection from the Local also simultaneously trying to establish a Connection from the Local
Endpoint candidates to the Remote Endpoint candidates. Endpoint candidates to the Remote Endpoint candidates.
If there are multiple Local Endpoints or Remote Endpoints configured, If there are multiple Local Endpoints or Remote Endpoints configured,
then initiating a Rendezvous() action will systematically probe the then initiating a Rendezvous() action will systematically probe the
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Local Endpoint or Remote Endpoint cannot be resolved, when no Local Endpoint or Remote Endpoint cannot be resolved, when no
transport-layer connection can be established to the Remote Endpoint, transport-layer connection can be established to the Remote Endpoint,
or when the application is prohibited from rendezvous by policy: or when the application is prohibited from rendezvous by policy:
Preconnection -> EstablishmentError<reason?> Preconnection -> EstablishmentError<reason?>
7.4. Connection Groups 7.4. Connection Groups
Connection Groups can be created using the Clone Action: Connection Groups can be created using the Clone Action:
Connection := Connection.Clone(framer?) Connection := Connection.Clone(framer?, connectionProperties?)
Calling Clone on a Connection yields a Connection Group containing Calling Clone on a Connection yields a Connection Group containing
two Connections: the parent Connection on which Clone was called, and two Connections: the parent Connection on which Clone was called, and
a resulting cloned Connection. The new Connection is actively a resulting cloned Connection. The new Connection is actively
openend, and it will send a Ready Event or an EstablishmentError openend, and it will send a Ready Event or an EstablishmentError
Event. Calling Clone on any of these Connections adds another Event. Calling Clone on any of these Connections adds another
Connection to the Connection Group. Connections in a Connection Connection to the Connection Group. Connections in a Connection
Group share all Connection Properties except Connection Priority (see Group share all Connection Properties except connPriority (see
Section 8.1.2), and these Connection Properties are entangled: Section 8.1.2), and these Connection Properties are entangled:
Changing one of the Connection Properties on one Connection in the Changing one of the Connection Properties on one Connection in the
Connection Group automatically changes the Connection Property for Connection Group automatically changes the Connection Property for
all others. For example, changing Timeout for aborting Connection all others. For example, changing connTimeout (see Section 8.1.3) on
(see Section 8.1.3) on one Connection in a Connection Group will one Connection in a Connection Group will automatically make the same
automatically make the same change to this Connection Property for change to this Connection Property for all other Connections in the
all other Connections in the Connection Group. Like all other Connection Group. Like all other Properties, connPriority is copied
Properties, Connection Priority is copied to the new Connection when to the new Connection when calling Clone(), but in this case, a later
calling Clone(), but in this case, a later change to the Connection change to the connPriority on one Connection does not change it on
Priority on one Connection does not change it on the other the other Connections in the same Connection Group.
Connections in the same Connection Group.
The optional connectionProperties parameter allows passing Transport
Properties that control the behavior of the underlying stream or
connection to be created, e.g., protocol-specific properties to
request specific stream IDs for SCTP or QUIC.
Message Properties set on a Connection also apply only to that Message Properties set on a Connection also apply only to that
Connection. Connection.
A new Connection created by Clone can have a Message Framer assigned A new Connection created by Clone can have a Message Framer assigned
via the optional framer parameter of the Clone Action. If this via the optional framer parameter of the Clone Action. If this
parameter is not supplied, the stack of Message Framers associated parameter is not supplied, the stack of Message Framers associated
with a Connection is copied to the cloned Connection when calling with a Connection is copied to the cloned Connection when calling
Clone. Then, a cloned Connection has the same stack of Message Clone. Then, a cloned Connection has the same stack of Message
Framers as the Connection from which they are Cloned, but these Framers as the Connection from which they are Cloned, but these
Framers may internally maintain per-Connection state. Framers may internally maintain per-Connection state.
It is also possible to check which Connections belong to the same It is also possible to check which Connections belong to the same
Connection Group. Calling GroupedConnections() on a specific Connection Group. Calling GroupedConnections() on a specific
Connection returns a set of all Connections in the same group. Connection returns a set of all Connections in the same group.
[]Connection := Connection.GroupedConnections() []Connection := Connection.GroupedConnections()
Connections will belong to the same group if the application Connections will belong to the same group if the application
previously called Clone. Passive Connections can also be added to previously called Clone. Passive Connections can also be added to
the same group - e.g., when a Listener receives a new Connection that the same group -- e.g., when a Listener receives a new Connection
is just a new stream of an already active multi-streaming protocol that is just a new stream of an already active multi-streaming
instance. protocol instance.
If the underlying protocol supports multi-streaming, it is natural to If the underlying protocol supports multi-streaming, it is natural to
use this functionality to implement Clone. In that case, Connections use this functionality to implement Clone. In that case, Connections
in a Connection Group are multiplexed together, giving them similar in a Connection Group are multiplexed together, giving them similar
treatment not only inside endpoints, but also across the end-to-end treatment not only inside endpoints, but also across the end-to-end
Internet path. Internet path.
Note that calling Clone() can result in on-the-wire signaling, e.g., Note that calling Clone() can result in on-the-wire signaling, e.g.,
to open a new transport connection, depending on the underlying to open a new transport connection, depending on the underlying
Protocol Stack. When Clone() leads to the opening of multiple such Protocol Stack. When Clone() leads to the opening of multiple such
connections, the Transport Services system will ensure consistency of connections, the Transport Services system will ensure consistency of
Connection Properties by uniformly applying them to all underlying Connection Properties by uniformly applying them to all underlying
connections in a group. Even in such a case, there are possibilities connections in a group. Even in such a case, there are possibilities
for a Transport Services system to implement prioritization within a for a Transport Services system to implement prioritization within a
Connection Group [TCP-COUPLING] [RFC8699]. Connection Group [TCP-COUPLING] [RFC8699].
Attempts to clone a Connection can result in a CloneError: Attempts to clone a Connection can result in a CloneError:
Connection -> CloneError<reason?> Connection -> CloneError<reason?>
The Connection Priority Connection Property operates on Connections The connPriority Connection Property operates on Connections in a
in a Connection Group using the same approach as in Section 9.1.3.2: Connection Group using the same approach as in Section 9.1.3.2: when
when allocating available network capacity among Connections in a allocating available network capacity among Connections in a
Connection Group, sends on Connections with higher Priority values Connection Group, sends on Connections with higher Priority values
will be prioritized over sends on Connections that have lower will be prioritized over sends on Connections that have lower
Priority values. Capacity will be shared among these Connections Priority values. Capacity will be shared among these Connections
according to the Connection Group Transmission Scheduler property according to the connScheduler property (Section 8.1.5). See
(Section 8.1.5). See Section 9.2.6 for more. Section 9.2.6 for more.
7.5. Adding and Removing Endpoints on a Connection 7.5. Adding and Removing Endpoints on a Connection
Transport protocols that are explicitly multipath aware are expected Transport protocols that are explicitly multipath aware are expected
to automatically manage the set of Remote Endpoints that they are to automatically manage the set of Remote Endpoints that they are
communicating with, and the paths to those endpoints. A PathChange<> communicating with, and the paths to those endpoints. A PathChange<>
event, described in Section 8.3.2, will be generated when the path event, described in Section 8.3.2, will be generated when the path
changes. changes.
In some cases, however, it is necessary to explicitly indicate to a In some cases, however, it is necessary to explicitly indicate to a
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if ConnectionProperties.Has(boolean_or_preference_property) then ... if ConnectionProperties.Has(boolean_or_preference_property) then ...
Depending on the status of the connection, the queried Connection Depending on the status of the connection, the queried Connection
Properties will include different information: Properties will include different information:
* The connection state, which can be one of the following: * The connection state, which can be one of the following:
Establishing, Established, Closing, or Closed. Establishing, Established, Closing, or Closed.
* Whether the connection can be used to send data. A connection can * Whether the connection can be used to send data. A connection can
not be used for sending if the connection was created with the not be used for sending if the connection was created with the
Selection Property Direction of Communication set to Selection Property direction set to unidirectional receive or if a
unidirectional receive or if a Message marked as Final was sent Message marked as Final was sent over this connection. See also
over this connection. See also Section 9.1.3.5. Section 9.1.3.5.
* Whether the connection can be used to receive data. A connection * Whether the connection can be used to receive data. A connection
cannot be used for reading if the connection was created with the cannot be used for reading if the connection was created with the
Selection Property Direction of Communication set to Selection Property direction set to unidirectional send or if a
unidirectional send or if a Message marked as Final was received. Message marked as Final was received. See Section 9.3.3.3. The
See Section 9.3.3.3. The latter is only supported by certain latter is only supported by certain transport protocols, e.g., by
transport protocols, e.g., by TCP as half-closed connection. TCP as half-closed connection.
* For Connections that are Established, Closing, or Closed: * For Connections that are Established, Closing, or Closed:
Connection Properties (Section 8.1) of the actual protocols that Connection Properties (Section 8.1) of the actual protocols that
were selected and instantiated, and Selection Properties that the were selected and instantiated, and Selection Properties that the
application specified on the Preconnection. Selection Properties application specified on the Preconnection. Selection Properties
of type Preference will be exposed as boolean values indicating of type Preference will be exposed as boolean values indicating
whether or not the property applies to the selected transport. whether or not the property applies to the selected transport.
Note that the instantiated protocol stack might not match all Note that the instantiated protocol stack might not match all
Protocol Selection Properties that the application specified on Protocol Selection Properties that the application specified on
the Preconnection. the Preconnection.
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protocol stack and therefore available on all Connections. protocol stack and therefore available on all Connections.
Many Connection Properties have a corresponding Selection Property Many Connection Properties have a corresponding Selection Property
that enables applications to express their preference for protocols that enables applications to express their preference for protocols
providing a supporting transport feature. providing a supporting transport feature.
8.1.1. Required Minimum Corruption Protection Coverage for Receiving 8.1.1. Required Minimum Corruption Protection Coverage for Receiving
Name: recvChecksumLen Name: recvChecksumLen
Type: Integer or Full Coverage Type: Integer (non-negative) or Full Coverage
Default: Full Coverage Default: Full Coverage
If this property is an Integer, it specifies the minimum number of If this property is an Integer, it specifies the minimum number of
bytes in a received message that need to be covered by a checksum. A bytes in a received message that need to be covered by a checksum. A
receiving endpoint will not forward messages that have less coverage receiving endpoint will not forward messages that have less coverage
to the application. The application is responsible for handling any to the application. The application is responsible for handling any
corruption within the non-protected part of the message [RFC8085]. A corruption within the non-protected part of the message [RFC8085]. A
special value of 0 means that a received packet may also have a zero special value of 0 means that a received packet may also have a zero
checksum field. checksum field.
8.1.2. Connection Priority 8.1.2. Connection Priority
Name: connPriority Name: connPriority
Type: Integer (non-negative) Type: Integer (non-negative)
Default: 100 Default: 100
This Property is a non-negative integer representing the priority of This property is a non-negative integer representing the priority of
this Connection relative to other Connections in the same Connection this Connection relative to other Connections in the same Connection
Group. A higher value reflects a higher priority. It has no effect Group. A higher value reflects a higher priority. It has no effect
on Connections not part of a Connection Group. As noted in on Connections not part of a Connection Group. As noted in
Section 7.4, this property is not entangled when Connections are Section 7.4, this property is not entangled when Connections are
cloned, i.e., changing the Priority on one Connection in a Connection cloned, i.e., changing the Priority on one Connection in a Connection
Group does not change it on the other Connections in the same Group does not change it on the other Connections in the same
Connection Group. No guarantees of a specific behavior regarding Connection Group. No guarantees of a specific behavior regarding
Connection Priority are given; a Transport Services system may ignore Connection Priority are given; a Transport Services system may ignore
this property. See Section 9.2.6 for more details. this property. See Section 9.2.6 for more details.
8.1.3. Timeout for Aborting Connection 8.1.3. Timeout for Aborting Connection
Name: connTimeout Name: connTimeout
Type: Numeric or Disabled Type: Numeric (non-negative) or Disabled
Default: Disabled Default: Disabled
If this property is Numeric, it specifies how long to wait before If this property is Numeric, it specifies how long to wait before
deciding that an active Connection has failed when trying to reliably deciding that an active Connection has failed when trying to reliably
deliver data to the Remote Endpoint. Adjusting this Property will deliver data to the Remote Endpoint. Adjusting this property will
only take effect when the underlying stack supports reliability. If only take effect when the underlying stack supports reliability. If
this property has the enumerated value Disabled, it means that no this property has the enumerated value Disabled, it means that no
timeout is scheduled. timeout is scheduled.
8.1.4. Timeout for keep alive packets 8.1.4. Timeout for keep alive packets
Name: keepAliveTimeout Name: keepAliveTimeout
Type: Numeric or Disabled Type: Numeric (non-negative) or Disabled
Default: Implementation-defined Default: Implementation-defined
A Transport Services API can request a protocol that supports sending A Transport Services API can request a protocol that supports sending
keep alive packets Section 6.2.10. If this property is an Integer, keep alive packets Section 6.2.10. If this property is Numeric, it
it specifies the maximum length of time an idle connection (one for specifies the maximum length of time an idle connection (one for
which no transport packets have been sent) should wait before the which no transport packets have been sent) should wait before the
Local Endpoint sends a keep-alive packet to the Remote Endpoint. Local Endpoint sends a keep-alive packet to the Remote Endpoint.
Adjusting this Property will only take effect when the underlying Adjusting this property will only take effect when the underlying
stack supports sending keep-alive packets. Guidance on setting this stack supports sending keep-alive packets. Guidance on setting this
value for datagram transports is provided in [RFC8085]. A value value for connection-less transports is provided in [RFC8085]. A
greater than the connection timeout (Section 8.1.3) or the enumerated value greater than the connection timeout (Section 8.1.3) or the
value Disabled will disable the sending of keep-alive packets. enumerated value Disabled will disable the sending of keep-alive
packets.
8.1.5. Connection Group Transmission Scheduler 8.1.5. Connection Group Transmission Scheduler
Name: connScheduler Name: connScheduler
Type: Enumeration Type: Enumeration
Default: Weighted Fair Queueing (see Section 3.6 in [RFC8260]) Default: Weighted Fair Queueing (see Section 3.6 in [RFC8260])
This property specifies which scheduler should be used among This property specifies which scheduler should be used among
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connection DSCP signaling without multiplexing SHOULD assign a connection DSCP signaling without multiplexing SHOULD assign a
DSCP Assured Forwarding (AF11,AF12,AF13,AF14) [RFC2597] PHB per DSCP Assured Forwarding (AF11,AF12,AF13,AF14) [RFC2597] PHB per
Section 4.8 of [RFC4594]. Section 4.8 of [RFC4594].
The Capacity Profile for a selected protocol stack may be modified on The Capacity Profile for a selected protocol stack may be modified on
a per-Message basis using the Transmission Profile Message Property; a per-Message basis using the Transmission Profile Message Property;
see Section 9.1.3.8. see Section 9.1.3.8.
8.1.7. Policy for using Multipath Transports 8.1.7. Policy for using Multipath Transports
Name: multipath-policy Name: multipathPolicy
Type: Enumeration Type: Enumeration
Default: Handover Default: Handover
This property specifies the local policy for transferring data across This property specifies the local policy for transferring data across
multiple paths between the same end hosts if Multipath Transport is multiple paths between the same end hosts if Multipath Transport is
not set to Disabled (see Section 6.2.14). Possible values are: not set to Disabled (see Section 6.2.14). Possible values are:
Handover: The connection ought only to attempt to migrate between Handover: The connection ought only to attempt to migrate between
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capacity limitations of the individual paths. The actual strategy capacity limitations of the individual paths. The actual strategy
is implementation specific. is implementation specific.
Note that this is a local choice - the Remote Endpoint can choose a Note that this is a local choice - the Remote Endpoint can choose a
different policy. different policy.
8.1.8. Bounds on Send or Receive Rate 8.1.8. Bounds on Send or Receive Rate
Name: minSendRate / minRecvRate / maxSendRate / maxRecvRate Name: minSendRate / minRecvRate / maxSendRate / maxRecvRate
Type: Numeric or Unlimited / Numeric or Unlimited / Numeric or Type: Numeric (non-negative) or Unlimited / Numeric (non-negative)
Unlimited / Numeric or Unlimited or Unlimited / Numeric (non-negative) or Unlimited / Numeric (non-
negative) or Unlimited
Default: Unlimited / Unlimited / Unlimited / Unlimited Default: Unlimited / Unlimited / Unlimited / Unlimited
Integer values of this property specify an upper-bound rate that a Numeric values of this property specify an upper-bound rate that a
transfer is not expected to exceed (even if flow control and transfer is not expected to exceed (even if flow control and
congestion control allow higher rates), and/or a lower-bound rate congestion control allow higher rates), and/or a lower-bound rate
below which the application does not deem it will be useful. These below which the application does not deem it will be useful. These
are specified in bits per second. The enumerated value Unlimited are specified in bits per second. The enumerated value Unlimited
indicates that no bound is specified. indicates that no bound is specified.
8.1.9. Group Connection Limit 8.1.9. Group Connection Limit
Name: groupConnLimit Name: groupConnLimit
Type: Numeric or Unlimited Type: Numeric (non-negative) or Unlimited
Default: Unlimited Default: Unlimited
If this property is an Integer, it controls the number of Connections If this property is Numeric, it controls the number of Connections
that can be accepted from a peer as new members of the Connection's that can be accepted from a peer as new members of the Connection's
group. Similar to SetNewConnectionLimit(), this limits the number of group. Similar to SetNewConnectionLimit(), this limits the number of
ConnectionReceived Events that will occur, but constrained to the ConnectionReceived Events that will occur, but constrained to the
group of the Connection associated with this property. For a multi- group of the Connection associated with this property. For a multi-
streaming transport, this limits the number of allowed streams. streaming transport, this limits the number of allowed streams.
8.1.10. Isolate Session 8.1.10. Isolate Session
Name: isolateSession Name: isolateSession
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8.1.11. Read-only Connection Properties 8.1.11. Read-only Connection Properties
The following generic Connection Properties are read-only, i.e. they The following generic Connection Properties are read-only, i.e. they
cannot be changed by an application. cannot be changed by an application.
8.1.11.1. Maximum Message Size Concurrent with Connection Establishment 8.1.11.1. Maximum Message Size Concurrent with Connection Establishment
Name: zeroRttMsgMaxLen Name: zeroRttMsgMaxLen
Type: Integer Type: Integer (non-negative)
This property represents the maximum Message size that can be sent This property represents the maximum Message size that can be sent
before or during Connection establishment, see also Section 9.1.3.4. before or during Connection establishment, see also Section 9.1.3.4.
It is specified as the number of bytes. It is specified as the number of bytes.
8.1.11.2. Maximum Message Size Before Fragmentation or Segmentation 8.1.11.2. Maximum Message Size Before Fragmentation or Segmentation
Name: singularTransmissionMsgMaxLen Name: singularTransmissionMsgMaxLen
Type: Integer Type: Integer (non-negative) or Not applicable
This property, if applicable, represents the maximum Message size This property, if applicable, represents the maximum Message size
that can be sent without incurring network-layer fragmentation at the that can be sent without incurring network-layer fragmentation at the
sender. It is specified as the number of bytes. It exposes a value sender. It is specified as the number of bytes. It exposes a value
to the application based on the Maximum Packet Size (MPS) as to the application based on the Maximum Packet Size (MPS) as
described in Datagram PLPMTUD [RFC8899]. This can allow a sending described in Datagram PLPMTUD [RFC8899]. This can allow a sending
stack to avoid unwanted fragmentation at the network-layer or stack to avoid unwanted fragmentation at the network-layer or
segmentation by the transport layer. segmentation by the transport layer.
8.1.11.3. Maximum Message Size on Send 8.1.11.3. Maximum Message Size on Send
Name: sendMsgMaxLen Name: sendMsgMaxLen
Type: Integer Type: Integer (non-negative)
This property represents the maximum Message size that an application This property represents the maximum Message size that an application
can send. It is specified as the nummber of bytes. can send. It is specified as the number of bytes.
8.1.11.4. Maximum Message Size on Receive 8.1.11.4. Maximum Message Size on Receive
Name: recvMsgMaxLen Name: recvMsgMaxLen
Type: Integer Type: Integer (non-negative)
This numeric property represents the maximum Message size that an
application can receive. It specified as the number of bytes. This property represents the maximum Message size that an application
can receive. It specified as the number of bytes.
8.2. TCP-specific Properties: User Timeout Option (UTO) 8.2. TCP-specific Properties: User Timeout Option (UTO)
These properties specify configurations for the User Timeout Option These properties specify configurations for the User Timeout Option
(UTO), in the case that TCP becomes the chosen transport protocol. (UTO), in the case that TCP becomes the chosen transport protocol.
Implementation is optional and useful only if TCP is implemented in Implementation is optional and useful only if TCP is implemented in
the Transport Services system. the Transport Services system.
These TCP-specific properties are included here because the feature These TCP-specific properties are included here because the feature
Suggest timeout to the peer is part of the minimal set of transport Suggest timeout to the peer is part of the minimal set of transport
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All of the below properties are optional (e.g., it is possible to All of the below properties are optional (e.g., it is possible to
specify User Timeout Enabled as true, but not specify an Advertised specify User Timeout Enabled as true, but not specify an Advertised
User Timeout value; in this case, the TCP default will be used). User Timeout value; in this case, the TCP default will be used).
These properties reflect the API extension specified in Section 3 of These properties reflect the API extension specified in Section 3 of
[RFC5482]. [RFC5482].
8.2.1. Advertised User Timeout 8.2.1. Advertised User Timeout
Name: tcp.userTimeoutValue Name: tcp.userTimeoutValue
Type: Integer Type: Integer (non-negative)
Default: the TCP default Default: the TCP default
This time value is advertised via the TCP User Timeout Option (UTO) This time value is advertised via the TCP User Timeout Option (UTO)
[RFC5482] at the Remote Endpoint to adapt its own Timeout for [RFC5482] at the Remote Endpoint to adapt its own Timeout for
aborting Connection (see Section 8.1.3) value. aborting Connection (see Section 8.1.3) value.
8.2.2. User Timeout Enabled 8.2.2. User Timeout Enabled
Name: tcp.userTimeoutEnabled Name: tcp.userTimeoutEnabled
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connection. This applies to both sending and receiving. connection. This applies to both sending and receiving.
8.2.3. Timeout Changeable 8.2.3. Timeout Changeable
Name: tcp.userTimeoutChangeable Name: tcp.userTimeoutChangeable
Type: Boolean Type: Boolean
Default: true Default: true
This property controls whether the Timeout for aborting Connection This property controls whether the connTimeout (see Section 8.1.3)
(see Section 8.1.3) may be changed based on a UTO option received may be changed based on a UTO option received from the remote peer.
from the remote peer. This boolean becomes false when Timeout for This boolean becomes false when connTimeout (see Section 8.1.3) is
aborting Connection (see Section 8.1.3) is used. used.
8.3. Connection Lifecycle Events 8.3. Connection Lifecycle Events
During the lifetime of a connection there are events that can occur During the lifetime of a connection there are events that can occur
when configured. when configured.
8.3.1. Soft Errors 8.3.1. Soft Errors
Asynchronous introspection is also possible, via the SoftError Event. Asynchronous introspection is also possible, via the SoftError Event.
This event informs the application about the receipt and contents of This event informs the application about the receipt and contents of
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The Message Properties could be inconsistent with the properties of The Message Properties could be inconsistent with the properties of
the Protocol Stacks underlying the Connection on which a given the Protocol Stacks underlying the Connection on which a given
Message is sent. For example, a Protocol Stack must be able to Message is sent. For example, a Protocol Stack must be able to
provide ordering if the msgOrdered property of a Message is enabled. provide ordering if the msgOrdered property of a Message is enabled.
Sending a Message with Message Properties inconsistent with the Sending a Message with Message Properties inconsistent with the
Selection Properties of the Connection yields an error. Selection Properties of the Connection yields an error.
If a Message Property contradicts a Connection Property, and if this If a Message Property contradicts a Connection Property, and if this
per-Message behavior can be supported, it overrides the Connection per-Message behavior can be supported, it overrides the Connection
Property for the specific Message. For example, if Reliable Data Property for the specific Message. For example, if reliability is
Transfer (Connection) is set to Require and a protocol with set to Require and a protocol with configurable per-Message
configurable per-Message reliability is used, setting Reliable Data reliability is used, setting msgReliable to false for a particular
Transfer (Message) to false for a particular Message will allow this Message will allow this Message to be sent without any reliability
Message to be sent without any reliability guarantees. Changing the guarantees. Changing the msgReliable Message Property is only
Reliable Data Transfer property on Messages is only possible for possible for Connections that were established enabling the Selection
Connections that were established enabling the Selection Property Property perMsgReliability.
Configure Per-Message Reliability.
The following Message Properties are supported: The following Message Properties are supported:
9.1.3.1. Lifetime 9.1.3.1. Lifetime
Name: msgLifetime Name: msgLifetime
Type: Numeric Type: Numeric (non-negative)
Default: infinite Default: infinite
The Lifetime specifies how long a particular Message can wait to be The Lifetime specifies how long a particular Message can wait to be
sent to the Remote Endpoint before it is irrelevant and no longer sent to the Remote Endpoint before it is irrelevant and no longer
needs to be (re-)transmitted. This is a hint to the Transport needs to be (re-)transmitted. This is a hint to the Transport
Services implementation - it is not guaranteed that a Message will Services implementation -- it is not guaranteed that a Message will
not be sent when its Lifetime has expired. not be sent when its Lifetime has expired.
Setting a Message's Lifetime to infinite indicates that the Setting a Message's Lifetime to infinite indicates that the
application does not wish to apply a time constraint on the application does not wish to apply a time constraint on the
transmission of the Message, but it does not express a need for transmission of the Message, but it does not express a need for
reliable delivery; reliability is adjustable per Message via the reliable delivery; reliability is adjustable per Message via the
Reliable Data Transfer (Message) property (see Section 9.1.3.7). The perMsgReliability property (see Section 9.1.3.7). The type and units
type and units of Lifetime are implementation-specific. of Lifetime are implementation-specific.
9.1.3.2. Priority 9.1.3.2. Priority
Name: msgPriority Name: msgPriority
Type: Integer (non-negative) Type: Integer (non-negative)
Default: 100 Default: 100
This property specifies the priority of a Message, relative to other This property specifies the priority of a Message, relative to other
Messages sent over the same Connection. Messages sent over the same Connection.
A Message with Priority 0 will yield to a Message with Priority 1, A Message with Priority 0 will yield to a Message with Priority 1,
which will yield to a Message with Priority 2, and so on. Priorities which will yield to a Message with Priority 2, and so on. Priorities
may be used as a sender-side scheduling construct only, or be used to may be used as a sender-side scheduling construct only, or be used to
specify priorities on the wire for Protocol Stacks supporting specify priorities on the wire for Protocol Stacks supporting
prioritization. prioritization.
Note that this property is not a per-message override of the Note that this property is not a per-message override of connPriority
Connection Priority - see Section 8.1.2. The Priority properties may - see Section 8.1.2. The priority properties may interact, but can
interact, but can be used independently and be realized by different be used independently and be realized by different mechanisms; see
mechanisms; see Section 9.2.6. Section 9.2.6.
9.1.3.3. Ordered 9.1.3.3. Ordered
Name: msgOrdered Name: msgOrdered
Type: Boolean Type: Boolean
Default: the queried Boolean value of the Selection Property Default: the queried Boolean value of the Selection Property
preserveOrder (Section 6.2.4) preserveOrder (Section 6.2.4)
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preserveOrder of the Connection associated with the Send Action. preserveOrder of the Connection associated with the Send Action.
9.1.3.4. Safely Replayable 9.1.3.4. Safely Replayable
Name: safelyReplayable Name: safelyReplayable
Type: Boolean Type: Boolean
Default: false Default: false
If true, Safely Replayable specifies that a Message is safe to send If true, safelyReplayable specifies that a Message is safe to send to
to the Remote Endpoint more than once for a single Send Action. It the Remote Endpoint more than once for a single Send Action. It
marks the data as safe for certain 0-RTT establishment techniques, marks the data as safe for certain 0-RTT establishment techniques,
where retransmission of the 0-RTT data may cause the remote where retransmission of the 0-RTT data may cause the remote
application to receive the Message multiple times. application to receive the Message multiple times.
For protocols that do not protect against duplicated messages, e.g., For protocols that do not protect against duplicated messages, e.g.,
UDP, all messages need to be marked as Safely Replayable. To enable UDP, all messages need to be marked as "safely replayable" by
protocol selection to choose such a protocol, Safely Replayable needs enabling this property. To enable protocol selection to choose such
to be added to the TransportProperties passed to the Preconnection. a protocol, safelyReplayable needs to be added to the
If such a protocol was chosen, disabling Safely Replayable on TransportProperties passed to the Preconnection. If such a protocol
individual messages MUST result in a SendError. was chosen, disabling safelyReplayable on individual messages MUST
result in a SendError.
9.1.3.5. Final 9.1.3.5. Final
Name: final Name: final
Type: Boolean Type: Boolean
Default: false Default: false
If true, this indicates a Message is the last that the application If true, this indicates a Message is the last that the application
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Messages. The Final property overrides Priority and any other Messages. The Final property overrides Priority and any other
property that would re-order Messages. If another Message is sent property that would re-order Messages. If another Message is sent
after a Message marked as Final has already been sent on a after a Message marked as Final has already been sent on a
Connection, the Send Action for the new Message will cause a Connection, the Send Action for the new Message will cause a
SendError Event. SendError Event.
9.1.3.6. Sending Corruption Protection Length 9.1.3.6. Sending Corruption Protection Length
Name: msgChecksumLen Name: msgChecksumLen
Type: Integer or Full Coverage Type: Integer (non-negative) or Full Coverage
Default: Full Coverage Default: Full Coverage
If this property is an Integer, it specifies the minimum length of If this property is an Integer, it specifies the minimum length of
the section of a sent Message, starting from byte 0, that the the section of a sent Message, starting from byte 0, that the
application requires to be delivered without corruption due to lower application requires to be delivered without corruption due to lower
layer errors. It is used to specify options for simple integrity layer errors. It is used to specify options for simple integrity
protection via checksums. A value of 0 means that no checksum needs protection via checksums. A value of 0 means that no checksum needs
to be calculated, and the enumerated value Full Coverage means that to be calculated, and the enumerated value Full Coverage means that
the entire Message needs to be protected by a checksum. Only Full the entire Message needs to be protected by a checksum. Only Full
Coverage is guaranteed, any other requests are advisory, which may Coverage is guaranteed, any other requests are advisory, which may
result in Full Coverage being applied. result in Full Coverage being applied.
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Name: msgReliable Name: msgReliable
Type: Boolean Type: Boolean
Default: the queried Boolean value of the Selection Property Default: the queried Boolean value of the Selection Property
reliability (Section 6.2.1) reliability (Section 6.2.1)
When true, this property specifies that a Message should be sent in When true, this property specifies that a Message should be sent in
such a way that the transport protocol ensures all data is received such a way that the transport protocol ensures all data is received
on the other side without corruption. Changing the Reliable Data on the other side without corruption. Changing the msgReliable
Transfer property on Messages is only possible for Connections that property on Messages is only possible for Connections that were
were established enabling the Selection Property Configure Per- established enabling the Selection Property perMsgReliability. When
Message Reliability. When this is not the case, changing msgReliable this is not the case, changing msgReliable will generate an error.
will generate an error.
Disabling this property indicates that the Transport Services system Disabling this property indicates that the Transport Services system
may disable retransmissions or other reliability mechanisms for this may disable retransmissions or other reliability mechanisms for this
particular Message, but such disabling is not guaranteed. particular Message, but such disabling is not guaranteed.
If it is not configured by the application before sending, this If it is not configured by the application before sending, this
property's default value will be based on the Selection Property property's default value will be based on the Selection Property
reliability of the Connection associated with the Send Action. reliability of the Connection associated with the Send Action.
9.1.3.8. Message Capacity Profile Override 9.1.3.8. Message Capacity Profile Override
Name: msgCapacityProfile Name: msgCapacityProfile
Type: Enumeration Type: Enumeration
Default: inherited from the Connection Property connCapacityProfile Default: inherited from the Connection Property connCapacityProfile
(Section 8.1.6) (Section 8.1.6)
This enumerated property specifies the application's preferred This enumerated property specifies the application's preferred
tradeoffs for sending this Message; it is a per-Message override of tradeoffs for sending this Message; it is a per-Message override of
the Capacity Profile connection property (see Section 8.1.6). If it the connCapacityProfile Connection Property (see Section 8.1.6). If
is not configured by the application before sending, this property's it is not configured by the application before sending, this
default value will be based on the Connection Property property's default value will be based on the Connection Property
connCapacityProfile of the Connection associated with the Send connCapacityProfile of the Connection associated with the Send
Action. Action.
9.1.3.9. No Network-Layer Fragmentation 9.1.3.9. No Network-Layer Fragmentation
Name: noFragmentation Name: noFragmentation
Type: Boolean Type: Boolean
Default: false Default: false
This property specifies that a message should be sent and received This property specifies that a message should be sent and received
without network-layer fragmentation, if possible. It can be used to without network-layer fragmentation, if possible. It can be used to
avoid network layer fragmentation when transport segmentation is avoid network layer fragmentation when transport segmentation is
prefered. prefered.
This only takes effect when the transport uses a network layer that This only takes effect when the transport uses a network layer that
supports this functionality. When it does take effect, setting this supports this functionality. When it does take effect, setting this
property to true will cause the sender to avoid network-layer source property to true will cause the sender to avoid network-layer source
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Default: false Default: false
This property specifies that a message should be sent and received This property specifies that a message should be sent and received
without network-layer fragmentation, if possible. It can be used to without network-layer fragmentation, if possible. It can be used to
avoid network layer fragmentation when transport segmentation is avoid network layer fragmentation when transport segmentation is
prefered. prefered.
This only takes effect when the transport uses a network layer that This only takes effect when the transport uses a network layer that
supports this functionality. When it does take effect, setting this supports this functionality. When it does take effect, setting this
property to true will cause the sender to avoid network-layer source property to true will cause the sender to avoid network-layer source
frgementation. When using IPv4, this will result in the Don't fragmentation. When using IPv4, this will result in the Don't
Fragment bit being set in the IP header. Fragment bit being set in the IP header.
Attempts to send a message with this property that result in a size Attempts to send a message with this property that result in a size
greater than the transport's current estimate of its maximum packet greater than the transport's current estimate of its maximum packet
size (singularTransmissionMsgMaxLen) can result in transport size (singularTransmissionMsgMaxLen) can result in transport
segmentation when permitted, or in a SendError. segmentation when permitted, or in a SendError.
Note: noSegmentation should be used when it is desired to only send a Note: noSegmentation should be used when it is desired to only send a
message within a single network packet. message within a single network packet.
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Note: noSegmentation should be used when it is desired to only send a Note: noSegmentation should be used when it is desired to only send a
message within a single network packet. message within a single network packet.
9.1.3.10. No Segmentation 9.1.3.10. No Segmentation
Name: noSegmentation Name: noSegmentation
Type: Boolean Type: Boolean
Default: false Default: false
When set to true, this property requests the transport layer to not When set to true, this property requests the transport layer to not
provide segmentation of messages larger than the maximum size provide segmentation of messages larger than the maximum size
permitted by the network layer, and also to avoid network-layer permitted by the network layer, and also to avoid network-layer
source fragmentation of messages. When running over IPv4, setting source fragmentation of messages. When running over IPv4, setting
this property to true can result in a sending endpount setting the this property to true will result in a sending endpount setting the
Don't Fragment bit in the IPv4 header of packets generated by the Don't Fragment bit in the IPv4 header of packets generated by the
transport layer. An attempt to send a message that results in a size transport layer.
greater than the transport's current estimate of its maximum packet
size (singularTransmissionMsgMaxLen) will result in a SendError. An attempt to send a message that results in a size greater than the
This only takes effect when the transport and network layer support transport's current estimate of its maximum packet size
this functionality. (singularTransmissionMsgMaxLen) will result in a SendError. This
only takes effect when the transport and network layer support this
functionality.
9.2. Sending Data 9.2. Sending Data
Once a Connection has been established, it can be used for sending Once a Connection has been established, it can be used for sending
Messages. By default, Send enqueues a complete Message, and takes Messages. By default, Send enqueues a complete Message, and takes
optional per-Message properties (see Section 9.2.1). All Send optional per-Message properties (see Section 9.2.1). All Send
actions are asynchronous, and deliver Events (see Section 9.2.2). actions are asynchronous, and deliver Events (see Section 9.2.2).
Sending partial Messages for streaming large data is also supported Sending partial Messages for streaming large data is also supported
(see Section 9.2.3). (see Section 9.2.3).
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described in Section 9.2.3. described in Section 9.2.3.
9.2.1. Basic Sending 9.2.1. Basic Sending
The most basic form of sending on a connection involves enqueuing a The most basic form of sending on a connection involves enqueuing a
single Data block as a complete Message with default Message single Data block as a complete Message with default Message
Properties. Properties.
messageData := "hello" messageData := "hello"
Connection.Send(messageData) Connection.Send(messageData)
The interpretation of a Message to be sent is dependent on the The interpretation of a Message to be sent is dependent on the
implementation, and on the constraints on the Protocol Stacks implied implementation, and on the constraints on the Protocol Stacks implied
by the Connection's transport properties. For example, a Message may by the Connection's transport properties. For example, a Message may
be a single datagram for UDP Connections; or an HTTP Request for HTTP be a single datagram for UDP Connections; or an HTTP Request for HTTP
Connections. Connections.
Some transport protocols can deliver arbitrarily sized Messages, but Some transport protocols can deliver arbitrarily sized Messages, but
other protocols constrain the maximum Message size. Applications can other protocols constrain the maximum Message size. Applications can
query the Connection Property "Maximum Message size on send" query the Connection Property sendMsgMaxLen (Section 8.1.11.3) to
(Section 8.1.11.3) to determine the maximum size allowed for a single determine the maximum size allowed for a single Message. If a
Message. If a Message is too large to fit in the Maximum Message Message is too large to fit in the Maximum Message Size for the
Size for the Connection, the Send will fail with a SendError event Connection, the Send will fail with a SendError event
(Section 9.2.2.3). For example, it is invalid to send a Message over (Section 9.2.2.3). For example, it is invalid to send a Message over
a UDP connection that is larger than the available datagram sending a UDP connection that is larger than the available datagram sending
size. size.
9.2.2. Send Events 9.2.2. Send Events
Like all Actions in Transport Services API, the Send Action is Like all Actions in Transport Services API, the Send Action is
asynchronous. There are several Events that can be delivered in asynchronous. There are several Events that can be delivered in
response to Sending a Message. Exactly one Event (Sent, Expired, or response to Sending a Message. Exactly one Event (Sent, Expired, or
SendError) will be delivered in response to each call to Send. SendError) will be delivered in response to each call to Send.
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9.2.5. Send on Active Open: InitiateWithSend 9.2.5. Send on Active Open: InitiateWithSend
For application-layer protocols where the Connection initiator also For application-layer protocols where the Connection initiator also
sends the first message, the InitiateWithSend() action combines sends the first message, the InitiateWithSend() action combines
Connection initiation with a first Message sent: Connection initiation with a first Message sent:
Connection := Preconnection.InitiateWithSend(messageData, messageContext?, timeout?) Connection := Preconnection.InitiateWithSend(messageData, messageContext?, timeout?)
Whenever possible, a messageContext should be provided to declare the Whenever possible, a messageContext should be provided to declare the
Message passed to InitiateWithSend as Safely Replayable. This allows Message passed to InitiateWithSend as "safely replayable" using the
the Transport Services system to make use of 0-RTT establishment in safelyReplayable property. This allows the Transport Services system
case this is supported by the available protocol stacks. When the to make use of 0-RTT establishment in case this is supported by the
selected stack(s) do not support transmitting data upon connection available protocol stacks. When the selected stack(s) do not support
establishment, InitiateWithSend is identical to Initiate() followed transmitting data upon connection establishment, InitiateWithSend is
by Send(). identical to Initiate() followed by Send().
Neither partial sends nor send batching are supported by Neither partial sends nor send batching are supported by
InitiateWithSend(). InitiateWithSend().
The Events that may be sent after InitiateWithSend() are equivalent The Events that may be sent after InitiateWithSend() are equivalent
to those that would be sent by an invocation of Initiate() followed to those that would be sent by an invocation of Initiate() followed
immediately by an invocation of Send(), with the caveat that a send immediately by an invocation of Send(), with the caveat that a send
failure that occurs because the Connection could not be established failure that occurs because the Connection could not be established
will not result in a SendError separate from the EstablishmentError will not result in a SendError separate from the EstablishmentError
signaling the failure of Connection establishment. signaling the failure of Connection establishment.
9.2.6. Priority and the Transport Services API 9.2.6. Priority and the Transport Services API
The Transport Services API provides two properties to allow a sender The Transport Services API provides two properties to allow a sender
to signal the relative priority of data transmission: the Priority to signal the relative priority of data transmission: msgPriority
Message Property Section 9.1.3.2, and the Connection Priority Section 9.1.3.2 and connPriority Section 8.1.2. These properties are
Connection Property Section 8.1.2. These properties are designed to designed to allow the expression and implementation of a wide variety
allow the expression and implementation of a wide variety of of approaches to transmission priority in the transport and
approaches to transmission priority in the transport and application application layer, including those which do not appear on the wire
layer, including those which do not appear on the wire (affecting (affecting only sender-side transmission scheduling) as well as those
only sender-side transmission scheduling) as well as those that do that do (e.g. [I-D.ietf-httpbis-priority].
(e.g. [I-D.ietf-httpbis-priority].
A Transport Services system gives no guarantees about how its A Transport Services system gives no guarantees about how its
expression of relative priorities will be realized. However, the expression of relative priorities will be realized. However, the
Transport Services system will seek to ensure that performance of Transport Services system will seek to ensure that performance of
relatively-prioritized connections and messages is not worse with relatively-prioritized connections and messages is not worse with
respect to those connections and messages than an equivalent respect to those connections and messages than an equivalent
configuration in which all prioritization properties are left at configuration in which all prioritization properties are left at
their defaults. their defaults.
The Transport Services API does order Connection Priority over the The Transport Services API does order connPriority over msgPriority.
Priority Message Property. In the absense of other externalities In the absense of other externalities (e.g., transport-layer flow
(e.g., transport-layer flow control), a priority 1 Message on a control), a priority 1 Message on a priority 0 Connection will be
priority 0 Connection will be sent before a priority 0 Message on a sent before a priority 0 Message on a priority 1 Connection in the
priority 1 Connection in the same group. same group.
9.3. Receiving Data 9.3. Receiving Data
Once a Connection is established, it can be used for receiving data Once a Connection is established, it can be used for receiving data
(unless the Direction of Communication property is set to (unless the direction property is set to unidirectional send). As
unidirectional send). As with sending, the data is received in with sending, the data is received in Messages. Receiving is an
Messages. Receiving is an asynchronous operation, in which each call asynchronous operation, in which each call to Receive enqueues a
to Receive enqueues a request to receive new data from the request to receive new data from the connection. Once data has been
connection. Once data has been received, or an error is encountered, received, or an error is encountered, an event will be delivered to
an event will be delivered to complete any pending Receive requests complete any pending Receive requests (see Section 9.3.2). If
(see Section 9.3.2). If Messages arrive at the Transport Services Messages arrive at the Transport Services system before Receive
system before Receive requests are issued, ensuing Receive requests requests are issued, ensuing Receive requests will first operate on
will first operate on these Messages before awaiting any further these Messages before awaiting any further Messages.
Messages.
9.3.1. Enqueuing Receives 9.3.1. Enqueuing Receives
Receive takes two parameters to specify the length of data that an Receive takes two parameters to specify the length of data that an
application is willing to receive, both of which are optional and application is willing to receive, both of which are optional and
have default values if not specified. have default values if not specified.
Connection.Receive(minIncompleteLength?, maxLength?) Connection.Receive(minIncompleteLength?, maxLength?)
By default, Receive will try to deliver complete Messages in a single By default, Receive will try to deliver complete Messages in a single
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A ReceiveError occurs when data is received by the underlying A ReceiveError occurs when data is received by the underlying
Protocol Stack that cannot be fully retrieved or parsed, and when it Protocol Stack that cannot be fully retrieved or parsed, and when it
is useful for the application to be notified of such errors. For is useful for the application to be notified of such errors. For
example, a ReceiveError can indicate that a Message (identified via example, a ReceiveError can indicate that a Message (identified via
the MessageContext) that was being partially received previously, but the MessageContext) that was being partially received previously, but
had not completed, encountered an error and will not be completed. had not completed, encountered an error and will not be completed.
This can be useful for an application, which may want to use this This can be useful for an application, which may want to use this
error as a hint to remove previously received Message parts from error as a hint to remove previously received Message parts from
memory. As another example, if an incoming Message does not fulfill memory. As another example, if an incoming Message does not fulfill
the Required Minimum Corruption Protection Coverage for Receiving the recvChecksumLen property (see Section 8.1.1), an application can
property (see Section 8.1.1), an application can use this error as a use this error as a hint to inform the peer application to adjust the
hint to inform the peer application to adjust the Sending Corruption msgChecksumLen property (see Section 9.1.3.6).
Protection Length property (see Section 9.1.3.6).
In contrast, internal protocol reception errors (e.g., loss causing In contrast, internal protocol reception errors (e.g., loss causing
retransmissions in TCP) are not signalled by this Event. Conditions retransmissions in TCP) are not signalled by this Event. Conditions
that irrevocably lead to the termination of the Connection are that irrevocably lead to the termination of the Connection are
signaled using ConnectionError (see Section 10). signaled using ConnectionError (see Section 10).
9.3.3. Receive Message Properties 9.3.3. Receive Message Properties
Each Message Context may contain metadata from protocols in the Each Message Context may contain metadata from protocols in the
Protocol Stack; which metadata is available is Protocol Stack Protocol Stack; which metadata is available is Protocol Stack
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data is enabled, applications should check this metadata field for data is enabled, applications should check this metadata field for
Messages received during connection establishment and respond Messages received during connection establishment and respond
accordingly. accordingly.
9.3.3.3. Receiving Final Messages 9.3.3.3. Receiving Final Messages
The Message Context can indicate whether or not this Message is the The Message Context can indicate whether or not this Message is the
Final Message on a Connection. For any Message that is marked as Final Message on a Connection. For any Message that is marked as
Final, the application can assume that there will be no more Messages Final, the application can assume that there will be no more Messages
received on the Connection once the Message has been completely received on the Connection once the Message has been completely
delivered. This corresponds to the Final property that may be marked delivered. This corresponds to the final property that may be marked
on a sent Message, see Section 9.1.3.5. on a sent Message, see Section 9.1.3.5.
Some transport protocols and peers do not support signaling of the Some transport protocols and peers do not support signaling of the
Final property. Applications therefore should not rely on receiving final property. Applications therefore should not rely on receiving
a Message marked Final to know that the sending endpoint is done a Message marked Final to know that the sending endpoint is done
sending on a connection. sending on a connection.
Any calls to Receive once the Final Message has been delivered will Any calls to Receive once the Final Message has been delivered will
result in errors. result in errors.
10. Connection Termination 10. Connection Termination
A Connection can be terminated i) by the Local Endpoint (i.e., the A Connection can be terminated i) by the Local Endpoint (i.e., the
application calls the Close, CloseGroup, Abort or AbortGroup Action), application calls the Close, CloseGroup, Abort or AbortGroup Action),
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However, as the Transport Services system is responsible for network However, as the Transport Services system is responsible for network
communication, it is in the position to potentially share any communication, it is in the position to potentially share any
information provided by the application with the network or another information provided by the application with the network or another
communication peer. Most of the information provided over the communication peer. Most of the information provided over the
Transport Services API are useful to configure and select protocols Transport Services API are useful to configure and select protocols
and paths and are not necessarily privacy sensitive. Still, some and paths and are not necessarily privacy sensitive. Still, some
information could be privacy sensitive because it might reveal usage information could be privacy sensitive because it might reveal usage
characteristics and habits of the user of an application. characteristics and habits of the user of an application.
Of course any communication over a network reveals usage Of course any communication over a network reveals usage
characteristics, as all packets, as well as their timing and size, characteristics, because all packets, as well as their timing and
are part of the network-visible wire image [RFC8546]. However, the size, are part of the network-visible wire image [RFC8546]. However,
selection of a protocol and its configuration also impacts which the selection of a protocol and its configuration also impacts which
information is visible, potentially in clear text, and which other information is visible, potentially in clear text, and which other
entities can access it. In most cases, information provided for entities can access it. In most cases, information provided for
protocol and path selection should not directly translate to protocol and path selection should not directly translate to
information that can be observed by network devices on the path. information that can be observed by network devices on the path.
However, there might be specific configuration information that is However, there might be specific configuration information that is
intended for path exposure, e.g., a DiffServ codepoint setting, that intended for path exposure, e.g., a DiffServ codepoint setting, that
is either provided directly by the application or indirectly is either provided directly by the application or indirectly
configured for a traffic profile. configured for a traffic profile.
Applications should be aware that communication attempts can lead to Applications should be aware that communication attempts can lead to
skipping to change at page 77, line 52 skipping to change at page 78, line 10
These communication activities are not different from what is used These communication activities are not different from what is used
today. However, the goal of a Transport Services system is to today. However, the goal of a Transport Services system is to
support such mechanisms as a generic service within the transport support such mechanisms as a generic service within the transport
layer. This enables applications to more dynamically benefit from layer. This enables applications to more dynamically benefit from
innovations and new protocols in the transport, although it reduces innovations and new protocols in the transport, although it reduces
transparency of the underlying communication actions to the transparency of the underlying communication actions to the
application itself. The Transport Services API is designed such that application itself. The Transport Services API is designed such that
protocol and path selection can be limited to a small and controlled protocol and path selection can be limited to a small and controlled
set if required by the application for functional or security set if required by the application for functional or security
purposes. Further, A Transport Services system should provide an purposes. Further, a Transport Services system should provide an
interface to poll information about which protocol and path is interface to poll information about which protocol and path is
currently in use as well as provide logging about the communication currently in use as well as provide logging about the communication
events of each connection. events of each connection.
14. Acknowledgements 14. Acknowledgements
This work has received funding from the European Union's Horizon 2020 This work has received funding from the European Union's Horizon 2020
research and innovation programme under grant agreements No. 644334 research and innovation programme under grant agreements No. 644334
(NEAT) and No. 688421 (MAMI). (NEAT) and No. 688421 (MAMI).
skipping to change at page 78, line 39 skipping to change at page 78, line 46
good questions based on implementation experience and for good questions based on implementation experience and for
contributing text, e.g., on multicast. contributing text, e.g., on multicast.
15. References 15. References
15.1. Normative References 15.1. Normative References
[I-D.ietf-taps-arch] [I-D.ietf-taps-arch]
Pauly, T., Trammell, B., Brunstrom, A., Fairhurst, G., and Pauly, T., Trammell, B., Brunstrom, A., Fairhurst, G., and
C. Perkins, "An Architecture for Transport Services", Work C. Perkins, "An Architecture for Transport Services", Work
in Progress, Internet-Draft, draft-ietf-taps-arch-12, 3 in Progress, Internet-Draft, draft-ietf-taps-arch-13, 27
January 2022, <https://www.ietf.org/archive/id/draft-ietf- June 2022, <https://datatracker.ietf.org/doc/html/draft-
taps-arch-12.txt>. ietf-taps-arch-13>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/rfc/rfc2119>.
[RFC2914] Floyd, S., "Congestion Control Principles", BCP 41, [RFC2914] Floyd, S., "Congestion Control Principles", BCP 41,
RFC 2914, DOI 10.17487/RFC2914, September 2000, RFC 2914, DOI 10.17487/RFC2914, September 2000,
<https://www.rfc-editor.org/info/rfc2914>. <https://www.rfc-editor.org/rfc/rfc2914>.
[RFC8084] Fairhurst, G., "Network Transport Circuit Breakers", [RFC8084] Fairhurst, G., "Network Transport Circuit Breakers",
BCP 208, RFC 8084, DOI 10.17487/RFC8084, March 2017, BCP 208, RFC 8084, DOI 10.17487/RFC8084, March 2017,
<https://www.rfc-editor.org/info/rfc8084>. <https://www.rfc-editor.org/rfc/rfc8084>.
[RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage [RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage
Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085, Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085,
March 2017, <https://www.rfc-editor.org/info/rfc8085>. March 2017, <https://www.rfc-editor.org/rfc/rfc8085>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC8303] Welzl, M., Tuexen, M., and N. Khademi, "On the Usage of [RFC8303] Welzl, M., Tuexen, M., and N. Khademi, "On the Usage of
Transport Features Provided by IETF Transport Protocols", Transport Features Provided by IETF Transport Protocols",
RFC 8303, DOI 10.17487/RFC8303, February 2018, RFC 8303, DOI 10.17487/RFC8303, February 2018,
<https://www.rfc-editor.org/info/rfc8303>. <https://www.rfc-editor.org/rfc/rfc8303>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>. <https://www.rfc-editor.org/rfc/rfc8446>.
[RFC8981] Gont, F., Krishnan, S., Narten, T., and R. Draves, [RFC8981] Gont, F., Krishnan, S., Narten, T., and R. Draves,
"Temporary Address Extensions for Stateless Address "Temporary Address Extensions for Stateless Address
Autoconfiguration in IPv6", RFC 8981, Autoconfiguration in IPv6", RFC 8981,
DOI 10.17487/RFC8981, February 2021, DOI 10.17487/RFC8981, February 2021,
<https://www.rfc-editor.org/info/rfc8981>. <https://www.rfc-editor.org/rfc/rfc8981>.
15.2. Informative References 15.2. Informative References
[I-D.ietf-httpbis-priority] [I-D.ietf-httpbis-priority]
Oku, K. and L. Pardue, "Extensible Prioritization Scheme Oku, K. and L. Pardue, "Extensible Prioritization Scheme
for HTTP", Work in Progress, Internet-Draft, draft-ietf- for HTTP", Work in Progress, Internet-Draft, draft-ietf-
httpbis-priority-12, 17 January 2022, httpbis-priority-12, 17 January 2022,
<https://www.ietf.org/archive/id/draft-ietf-httpbis- <https://datatracker.ietf.org/doc/html/draft-ietf-httpbis-
priority-12.txt>. priority-12>.
[I-D.ietf-taps-impl] [I-D.ietf-taps-impl]
Brunstrom, A., Pauly, T., Enghardt, T., Tiesel, P. S., and Brunstrom, A., Pauly, T., Enghardt, T., Tiesel, P. S., and
M. Welzl, "Implementing Interfaces to Transport Services", M. Welzl, "Implementing Interfaces to Transport Services",
Work in Progress, Internet-Draft, draft-ietf-taps-impl-11, Work in Progress, Internet-Draft, draft-ietf-taps-impl-12,
9 January 2022, <https://www.ietf.org/archive/id/draft- 7 March 2022, <https://datatracker.ietf.org/doc/html/
ietf-taps-impl-11.txt>. draft-ietf-taps-impl-12>.
[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, [RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS "Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", RFC 2474, Field) in the IPv4 and IPv6 Headers", RFC 2474,
DOI 10.17487/RFC2474, December 1998, DOI 10.17487/RFC2474, December 1998,
<https://www.rfc-editor.org/info/rfc2474>. <https://www.rfc-editor.org/rfc/rfc2474>.
[RFC2597] Heinanen, J., Baker, F., Weiss, W., and J. Wroclawski, [RFC2597] Heinanen, J., Baker, F., Weiss, W., and J. Wroclawski,
"Assured Forwarding PHB Group", RFC 2597, "Assured Forwarding PHB Group", RFC 2597,
DOI 10.17487/RFC2597, June 1999, DOI 10.17487/RFC2597, June 1999,
<https://www.rfc-editor.org/info/rfc2597>. <https://www.rfc-editor.org/rfc/rfc2597>.
[RFC3246] Davie, B., Charny, A., Bennet, J.C.R., Benson, K., Le [RFC3246] Davie, B., Charny, A., Bennet, J.C.R., Benson, K., Le
Boudec, J.Y., Courtney, W., Davari, S., Firoiu, V., and D. Boudec, J.Y., Courtney, W., Davari, S., Firoiu, V., and D.
Stiliadis, "An Expedited Forwarding PHB (Per-Hop Stiliadis, "An Expedited Forwarding PHB (Per-Hop
Behavior)", RFC 3246, DOI 10.17487/RFC3246, March 2002, Behavior)", RFC 3246, DOI 10.17487/RFC3246, March 2002,
<https://www.rfc-editor.org/info/rfc3246>. <https://www.rfc-editor.org/rfc/rfc3246>.
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E. A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261, Schooler, "SIP: Session Initiation Protocol", RFC 3261,
DOI 10.17487/RFC3261, June 2002, DOI 10.17487/RFC3261, June 2002,
<https://www.rfc-editor.org/info/rfc3261>. <https://www.rfc-editor.org/rfc/rfc3261>.
[RFC3376] Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A. [RFC3376] Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A.
Thyagarajan, "Internet Group Management Protocol, Version Thyagarajan, "Internet Group Management Protocol, Version
3", RFC 3376, DOI 10.17487/RFC3376, October 2002, 3", RFC 3376, DOI 10.17487/RFC3376, October 2002,
<https://www.rfc-editor.org/info/rfc3376>. <https://www.rfc-editor.org/rfc/rfc3376>.
[RFC4594] Babiarz, J., Chan, K., and F. Baker, "Configuration [RFC4594] Babiarz, J., Chan, K., and F. Baker, "Configuration
Guidelines for DiffServ Service Classes", RFC 4594, Guidelines for DiffServ Service Classes", RFC 4594,
DOI 10.17487/RFC4594, August 2006, DOI 10.17487/RFC4594, August 2006,
<https://www.rfc-editor.org/info/rfc4594>. <https://www.rfc-editor.org/rfc/rfc4594>.
[RFC4604] Holbrook, H., Cain, B., and B. Haberman, "Using Internet [RFC4604] Holbrook, H., Cain, B., and B. Haberman, "Using Internet
Group Management Protocol Version 3 (IGMPv3) and Multicast Group Management Protocol Version 3 (IGMPv3) and Multicast
Listener Discovery Protocol Version 2 (MLDv2) for Source- Listener Discovery Protocol Version 2 (MLDv2) for Source-
Specific Multicast", RFC 4604, DOI 10.17487/RFC4604, Specific Multicast", RFC 4604, DOI 10.17487/RFC4604,
August 2006, <https://www.rfc-editor.org/info/rfc4604>. August 2006, <https://www.rfc-editor.org/rfc/rfc4604>.
[RFC5245] Rosenberg, J., "Interactive Connectivity Establishment [RFC5245] Rosenberg, J., "Interactive Connectivity Establishment
(ICE): A Protocol for Network Address Translator (NAT) (ICE): A Protocol for Network Address Translator (NAT)
Traversal for Offer/Answer Protocols", RFC 5245, Traversal for Offer/Answer Protocols", RFC 5245,
DOI 10.17487/RFC5245, April 2010, DOI 10.17487/RFC5245, April 2010,
<https://www.rfc-editor.org/info/rfc5245>. <https://www.rfc-editor.org/rfc/rfc5245>.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
<https://www.rfc-editor.org/info/rfc5280>. <https://www.rfc-editor.org/rfc/rfc5280>.
[RFC5482] Eggert, L. and F. Gont, "TCP User Timeout Option", [RFC5482] Eggert, L. and F. Gont, "TCP User Timeout Option",
RFC 5482, DOI 10.17487/RFC5482, March 2009, RFC 5482, DOI 10.17487/RFC5482, March 2009,
<https://www.rfc-editor.org/info/rfc5482>. <https://www.rfc-editor.org/rfc/rfc5482>.
[RFC5865] Baker, F., Polk, J., and M. Dolly, "A Differentiated [RFC5865] Baker, F., Polk, J., and M. Dolly, "A Differentiated
Services Code Point (DSCP) for Capacity-Admitted Traffic", Services Code Point (DSCP) for Capacity-Admitted Traffic",
RFC 5865, DOI 10.17487/RFC5865, May 2010, RFC 5865, DOI 10.17487/RFC5865, May 2010,
<https://www.rfc-editor.org/info/rfc5865>. <https://www.rfc-editor.org/rfc/rfc5865>.
[RFC7478] Holmberg, C., Hakansson, S., and G. Eriksson, "Web Real- [RFC7478] Holmberg, C., Hakansson, S., and G. Eriksson, "Web Real-
Time Communication Use Cases and Requirements", RFC 7478, Time Communication Use Cases and Requirements", RFC 7478,
DOI 10.17487/RFC7478, March 2015, DOI 10.17487/RFC7478, March 2015,
<https://www.rfc-editor.org/info/rfc7478>. <https://www.rfc-editor.org/rfc/rfc7478>.
[RFC7556] Anipko, D., Ed., "Multiple Provisioning Domain [RFC7556] Anipko, D., Ed., "Multiple Provisioning Domain
Architecture", RFC 7556, DOI 10.17487/RFC7556, June 2015, Architecture", RFC 7556, DOI 10.17487/RFC7556, June 2015,
<https://www.rfc-editor.org/info/rfc7556>. <https://www.rfc-editor.org/rfc/rfc7556>.
[RFC7657] Black, D., Ed. and P. Jones, "Differentiated Services [RFC7657] Black, D., Ed. and P. Jones, "Differentiated Services
(Diffserv) and Real-Time Communication", RFC 7657, (Diffserv) and Real-Time Communication", RFC 7657,
DOI 10.17487/RFC7657, November 2015, DOI 10.17487/RFC7657, November 2015,
<https://www.rfc-editor.org/info/rfc7657>. <https://www.rfc-editor.org/rfc/rfc7657>.
[RFC8095] Fairhurst, G., Ed., Trammell, B., Ed., and M. Kuehlewind, [RFC8095] Fairhurst, G., Ed., Trammell, B., Ed., and M. Kuehlewind,
Ed., "Services Provided by IETF Transport Protocols and Ed., "Services Provided by IETF Transport Protocols and
Congestion Control Mechanisms", RFC 8095, Congestion Control Mechanisms", RFC 8095,
DOI 10.17487/RFC8095, March 2017, DOI 10.17487/RFC8095, March 2017,
<https://www.rfc-editor.org/info/rfc8095>. <https://www.rfc-editor.org/rfc/rfc8095>.
[RFC8229] Pauly, T., Touati, S., and R. Mantha, "TCP Encapsulation [RFC8229] Pauly, T., Touati, S., and R. Mantha, "TCP Encapsulation
of IKE and IPsec Packets", RFC 8229, DOI 10.17487/RFC8229, of IKE and IPsec Packets", RFC 8229, DOI 10.17487/RFC8229,
August 2017, <https://www.rfc-editor.org/info/rfc8229>. August 2017, <https://www.rfc-editor.org/rfc/rfc8229>.
[RFC8260] Stewart, R., Tuexen, M., Loreto, S., and R. Seggelmann, [RFC8260] Stewart, R., Tuexen, M., Loreto, S., and R. Seggelmann,
"Stream Schedulers and User Message Interleaving for the "Stream Schedulers and User Message Interleaving for the
Stream Control Transmission Protocol", RFC 8260, Stream Control Transmission Protocol", RFC 8260,
DOI 10.17487/RFC8260, November 2017, DOI 10.17487/RFC8260, November 2017,
<https://www.rfc-editor.org/info/rfc8260>. <https://www.rfc-editor.org/rfc/rfc8260>.
[RFC8293] Ghanwani, A., Dunbar, L., McBride, M., Bannai, V., and R. [RFC8293] Ghanwani, A., Dunbar, L., McBride, M., Bannai, V., and R.
Krishnan, "A Framework for Multicast in Network Krishnan, "A Framework for Multicast in Network
Virtualization over Layer 3", RFC 8293, Virtualization over Layer 3", RFC 8293,
DOI 10.17487/RFC8293, January 2018, DOI 10.17487/RFC8293, January 2018,
<https://www.rfc-editor.org/info/rfc8293>. <https://www.rfc-editor.org/rfc/rfc8293>.
[RFC8445] Keranen, A., Holmberg, C., and J. Rosenberg, "Interactive [RFC8445] Keranen, A., Holmberg, C., and J. Rosenberg, "Interactive
Connectivity Establishment (ICE): A Protocol for Network Connectivity Establishment (ICE): A Protocol for Network
Address Translator (NAT) Traversal", RFC 8445, Address Translator (NAT) Traversal", RFC 8445,
DOI 10.17487/RFC8445, July 2018, DOI 10.17487/RFC8445, July 2018,
<https://www.rfc-editor.org/info/rfc8445>. <https://www.rfc-editor.org/rfc/rfc8445>.
[RFC8489] Petit-Huguenin, M., Salgueiro, G., Rosenberg, J., Wing, [RFC8489] Petit-Huguenin, M., Salgueiro, G., Rosenberg, J., Wing,
D., Mahy, R., and P. Matthews, "Session Traversal D., Mahy, R., and P. Matthews, "Session Traversal
Utilities for NAT (STUN)", RFC 8489, DOI 10.17487/RFC8489, Utilities for NAT (STUN)", RFC 8489, DOI 10.17487/RFC8489,
February 2020, <https://www.rfc-editor.org/info/rfc8489>. February 2020, <https://www.rfc-editor.org/rfc/rfc8489>.
[RFC8546] Trammell, B. and M. Kuehlewind, "The Wire Image of a [RFC8546] Trammell, B. and M. Kuehlewind, "The Wire Image of a
Network Protocol", RFC 8546, DOI 10.17487/RFC8546, April Network Protocol", RFC 8546, DOI 10.17487/RFC8546, April
2019, <https://www.rfc-editor.org/info/rfc8546>. 2019, <https://www.rfc-editor.org/rfc/rfc8546>.
[RFC8622] Bless, R., "A Lower-Effort Per-Hop Behavior (LE PHB) for [RFC8622] Bless, R., "A Lower-Effort Per-Hop Behavior (LE PHB) for
Differentiated Services", RFC 8622, DOI 10.17487/RFC8622, Differentiated Services", RFC 8622, DOI 10.17487/RFC8622,
June 2019, <https://www.rfc-editor.org/info/rfc8622>. June 2019, <https://www.rfc-editor.org/rfc/rfc8622>.
[RFC8656] Reddy, T., Ed., Johnston, A., Ed., Matthews, P., and J. [RFC8656] Reddy, T., Ed., Johnston, A., Ed., Matthews, P., and J.
Rosenberg, "Traversal Using Relays around NAT (TURN): Rosenberg, "Traversal Using Relays around NAT (TURN):
Relay Extensions to Session Traversal Utilities for NAT Relay Extensions to Session Traversal Utilities for NAT
(STUN)", RFC 8656, DOI 10.17487/RFC8656, February 2020, (STUN)", RFC 8656, DOI 10.17487/RFC8656, February 2020,
<https://www.rfc-editor.org/info/rfc8656>. <https://www.rfc-editor.org/rfc/rfc8656>.
[RFC8699] Islam, S., Welzl, M., and S. Gjessing, "Coupled Congestion [RFC8699] Islam, S., Welzl, M., and S. Gjessing, "Coupled Congestion
Control for RTP Media", RFC 8699, DOI 10.17487/RFC8699, Control for RTP Media", RFC 8699, DOI 10.17487/RFC8699,
January 2020, <https://www.rfc-editor.org/info/rfc8699>. January 2020, <https://www.rfc-editor.org/rfc/rfc8699>.
[RFC8838] Ivov, E., Uberti, J., and P. Saint-Andre, "Trickle ICE: [RFC8838] Ivov, E., Uberti, J., and P. Saint-Andre, "Trickle ICE:
Incremental Provisioning of Candidates for the Interactive Incremental Provisioning of Candidates for the Interactive
Connectivity Establishment (ICE) Protocol", RFC 8838, Connectivity Establishment (ICE) Protocol", RFC 8838,
DOI 10.17487/RFC8838, January 2021, DOI 10.17487/RFC8838, January 2021,
<https://www.rfc-editor.org/info/rfc8838>. <https://www.rfc-editor.org/rfc/rfc8838>.
[RFC8899] Fairhurst, G., Jones, T., Tüxen, M., Rüngeler, I., and T. [RFC8899] Fairhurst, G., Jones, T., Tüxen, M., Rüngeler, I., and T.
Völker, "Packetization Layer Path MTU Discovery for Völker, "Packetization Layer Path MTU Discovery for
Datagram Transports", RFC 8899, DOI 10.17487/RFC8899, Datagram Transports", RFC 8899, DOI 10.17487/RFC8899,
September 2020, <https://www.rfc-editor.org/info/rfc8899>. September 2020, <https://www.rfc-editor.org/rfc/rfc8899>.
[RFC8922] Enghardt, T., Pauly, T., Perkins, C., Rose, K., and C. [RFC8922] Enghardt, T., Pauly, T., Perkins, C., Rose, K., and C.
Wood, "A Survey of the Interaction between Security Wood, "A Survey of the Interaction between Security
Protocols and Transport Services", RFC 8922, Protocols and Transport Services", RFC 8922,
DOI 10.17487/RFC8922, October 2020, DOI 10.17487/RFC8922, October 2020,
<https://www.rfc-editor.org/info/rfc8922>. <https://www.rfc-editor.org/rfc/rfc8922>.
[RFC8923] Welzl, M. and S. Gjessing, "A Minimal Set of Transport [RFC8923] Welzl, M. and S. Gjessing, "A Minimal Set of Transport
Services for End Systems", RFC 8923, DOI 10.17487/RFC8923, Services for End Systems", RFC 8923, DOI 10.17487/RFC8923,
October 2020, <https://www.rfc-editor.org/info/rfc8923>. October 2020, <https://www.rfc-editor.org/rfc/rfc8923>.
[TCP-COUPLING] [TCP-COUPLING]
Islam, S., Welzl, M., Hiorth, K., Hayes, D., Armitage, G., Islam, S., Welzl, M., Hiorth, K., Hayes, D., Armitage, G.,
and S. Gjessing, "ctrlTCP: Reducing Latency through and S. Gjessing, "ctrlTCP: Reducing Latency through
Coupled, Heterogeneous Multi-Flow TCP Congestion Control", Coupled, Heterogeneous Multi-Flow TCP Congestion Control",
IEEE INFOCOM Global Internet Symposium (GI) workshop (GI IEEE INFOCOM Global Internet Symposium (GI) workshop (GI
2018) , 2018. 2018) , 2018.
Appendix A. Implementation Mapping Appendix A. Implementation Mapping
skipping to change at page 84, line 27 skipping to change at page 84, line 33
A.3. Time Duration A.3. Time Duration
Time duration types are implementation-specific. For instance, it Time duration types are implementation-specific. For instance, it
could be a number of seconds, number of milliseconds, or a struct could be a number of seconds, number of milliseconds, or a struct
timeval in C or a user-defined Duration class in C++. timeval in C or a user-defined Duration class in C++.
Appendix B. Convenience Functions Appendix B. Convenience Functions
B.1. Adding Preference Properties B.1. Adding Preference Properties
As Selection Properties of type Preference will be set on a TransportProperties will frequently need to set Selection Properties
TransportProperties object quite frequently, implementations can of type Preference, therefore implementations can provide special
provide special actions for adding each preference level i.e, actions for adding each preference level i.e,
TransportProperties.Set(some_property, avoid) is equivalent to TransportProperties.Set(some_property, avoid) is equivalent
TransportProperties.Avoid(some_property): toTransportProperties.Avoid(some_property)`:
TransportProperties.Require(property) TransportProperties.Require(property)
TransportProperties.Prefer(property) TransportProperties.Prefer(property)
TransportProperties.Ignore(property) TransportProperties.Ignore(property)
TransportProperties.Avoid(property) TransportProperties.Avoid(property)
TransportProperties.Prohibit(property) TransportProperties.Prohibit(property)
B.2. Transport Property Profiles B.2. Transport Property Profiles
To ease the use of the Transport Services API specified by this To ease the use of the Transport Services API, implementations can
document, implementations can provide a mechanism to create Transport provide a mechanism to create Transport Property objects (see
Property objects (see Section 6.2) that are pre-configured with Section 6.2) that are pre-configured with frequently used sets of
frequently used sets of properties; the following are in common use properties; the following are in common use in current applications:
in current applications:
B.2.1. reliable-inorder-stream B.2.1. reliable-inorder-stream
This profile provides reliable, in-order transport service with This profile provides reliable, in-order transport service with
congestion control. TCP is an example of a protocol that provides congestion control. TCP is an example of a protocol that provides
this service. It should consist of the following properties: this service. It should consist of the following properties:
+=======================+=========+ +=======================+=========+
| Property | Value | | Property | Value |
+=======================+=========+ +=======================+=========+
skipping to change at page 86, line 16 skipping to change at page 86, line 16
| Property | Value | | Property | Value |
+=======================+=========+ +=======================+=========+
| reliability | avoid | | reliability | avoid |
+-----------------------+---------+ +-----------------------+---------+
| preserveOrder | avoid | | preserveOrder | avoid |
+-----------------------+---------+ +-----------------------+---------+
| congestionControl | ignore | | congestionControl | ignore |
+-----------------------+---------+ +-----------------------+---------+
| preserveMsgBoundaries | require | | preserveMsgBoundaries | require |
+-----------------------+---------+ +-----------------------+---------+
| safely replayable | true | | safelyReplayable | true |
+-----------------------+---------+ +-----------------------+---------+
Table 4: unreliable-datagram Table 4: unreliable-datagram
preferences preferences
Applications that choose this Transport Property Profile would avoid Applications that choose this Transport Property Profile would avoid
the additional latency that could be introduced by retransmission or the additional latency that could be introduced by retransmission or
reordering in a transport protocol. reordering in a transport protocol.
Applications that choose this Transport Property Profile to reduce Applications that choose this Transport Property Profile to reduce
skipping to change at page 87, line 9 skipping to change at page 87, line 9
with TCP, MPTCP, UDP, UDP-Lite, SCTP and LEDBAT. with TCP, MPTCP, UDP, UDP-Lite, SCTP and LEDBAT.
* Connect: Initiate Action (Section 7.1). * Connect: Initiate Action (Section 7.1).
* Listen: Listen Action (Section 7.2). * Listen: Listen Action (Section 7.2).
* Specify number of attempts and/or timeout for the first * Specify number of attempts and/or timeout for the first
establishment message: timeout parameter of Initiate (Section 7.1) establishment message: timeout parameter of Initiate (Section 7.1)
or InitiateWithSend Action (Section 9.2.5). or InitiateWithSend Action (Section 9.2.5).
* Disable MPTCP: multipath Property (Section 6.2.14). * Disable MPTCP: multipath property (Section 6.2.14).
* Hand over a message to reliably transfer (possibly multiple times) * Hand over a message to reliably transfer (possibly multiple times)
before connection establishment: InitiateWithSend Action before connection establishment: InitiateWithSend Action
(Section 9.2.5). (Section 9.2.5).
* Change timeout for aborting connection (using retransmit limit or * Change timeout for aborting connection (using retransmit limit or
time value): connTimeout property, using a time value time value): connTimeout property, using a time value
(Section 8.1.3). (Section 8.1.3).
* Timeout event when data could not be delivered for too long: * Timeout event when data could not be delivered for too long:
 End of changes. 125 change blocks. 
246 lines changed or deleted 249 lines changed or added

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