Network Working Group S. Floyd
Request for Comments: 5622 ICIR
Category: Experimental E. Kohler
UCLA
August 2009
Profile for Datagram Congestion Control Protocol (DCCP)
Congestion ID 4: TCP-Friendly Rate Control for Small Packets (TFRC-SP)
Abstract
This document specifies a profile for Congestion Control Identifier
4, the small-packet variant of TCP-Friendly Rate Control (TFRC), in
the Datagram Congestion Control Protocol (DCCP). CCID 4 is for
experimental use, and uses TFRC-SP (RFC 4828), a variant of TFRC
designed for applications that send small packets. CCID 4 is
considered experimental because TFRC-SP is itself experimental, and
is not proposed for widespread deployment in the global Internet at
this time. The goal for TFRC-SP is to achieve roughly the same
bandwidth in bits per second (bps) as a TCP flow using packets of up
to 1500 bytes but experiencing the same level of congestion. CCID 4
is for use for senders that send small packets and would like a TCP-
friendly sending rate, possibly with Explicit Congestion Notification
(ECN), while minimizing abrupt rate changes.
Status of This Memo
This memo defines an Experimental Protocol for the Internet
community. It does not specify an Internet standard of any kind.
Discussion and suggestions for improvement are requested.
Distribution of this memo is unlimited.
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Floyd & Kohler Experimental [Page 1]RFC 5622 Profile for DCCP CCID 4 August 2009
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Table of Contents
1. Introduction ....................................................3
2. Conventions .....................................................4
3. Usage ...........................................................4
3.1. Relationship with TFRC and TFRC-SP .........................5
3.2. Example Half-Connection ....................................5
4. Connection Establishment ........................................6
5. Congestion Control on Data Packets ..............................6
5.1. Response to Idle and Application-Limited Periods ...........7
5.2. Response to Data Dropped and Slow Receiver .................7
5.3. Packet Sizes ...............................................7
6. Acknowledgements ................................................8
6.1. Loss Interval Definition ...................................8
6.2. Congestion Control on Acknowledgements .....................8
6.3. Acknowledgements of Acknowledgements .......................8
6.4. Quiescence .................................................8
7. Explicit Congestion Notification ................................8
8. Options and Features ............................................9
8.1. Window Counter Value ......................................10
8.2. Elapsed Time Options ......................................10
8.3. Receive Rate Option .......................................10
8.4. Send Loss Event Rate Feature ..............................10
8.5. Loss Event Rate Option ....................................11
8.6. Loss Intervals Option .....................................11
8.7. Dropped Packets Option ....................................11
8.7.1. Example ............................................13
9. Verifying Congestion Control Compliance with ECN ...............14
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