TCP Maintenance and Minor Extensions (tcpm)

WG Name TCP Maintenance and Minor Extensions
Acronym tcpm
Area Transport Area (tsv)
State Active
Charter charter-ietf-tcpm-08 Approved
Status Update Show update (last changed 2017-02-27)
Dependencies Document dependency graph (SVG)
Additional URLs
- Wiki
- Issue tracker
Personnel Chairs Michael Scharf
Michael Tüxen
Yoshifumi Nishida
Area Director Mirja Kühlewind
Mailing list Address
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Charter for Working Group

TCP is currently the Internet's predominant transport protocol. TCPM
is the working group within the IETF that handles small TCP changes,
i.e., minor extensions to TCP algorithms and protocol mechanisms.
The TCPM WG serves several purposes:

* The WG mostly focuses on maintenance issues (e.g., bug fixes) and
modest changes to the protocol, algorithms, and interfaces that
maintain TCP's utility.

* The WG is a venue for moving current TCP specifications along the
standards track (as community energy is available for such efforts).

* The focus of the working group is TCP. In cases where small
changes are directly applicable to other transports (e.g., SCTP or
DCCP), the mappings to other transports may be specified alongside
that for TCP, but other significant additions and changes to other
transports are not in scope.

TCPM also provides a venue for standardization of incremental
enhancements of TCP's standard congestion control. In addition,
TCPM may document alternative TCP congestion control algorithms
that are known to be widely deployed, and that are considered
safe for large-scale deployment in the Internet. Changes of algorithms
may require additional review by the IRTF Congestion Control
Research Group (ICCRG). Fundamental changes to TCP or its congestion
control algorithms (e.g., departure from loss-based congestion
control) will be handled by other working groups or will require

TCP's congestion control algorithms are the model followed by
alternate transports (e.g., SCTP or DCCP), which are standardized in
other working groups, such as the Transport Area WG (tsvwg). In the
past, the IETF has worked on several documents about algorithms that
are specified for multiple protocols (e.g., TCP and SCTP) in the
same document. Which WG shepherds such documents will be determined
on a case-by-case basis. In any case, the TCPM WG will remain in
close contact with other relevant WGs working on these protocols to
ensure openness and stringent review from all angles.

New TCPM milestones that fall within the scope specified within the
charter can be added after consensus on acceptance in the working
group and approval by the responsible Area Director.


Date Milestone
Dec 2018 Submit document on TCP converters to the IESG for publication as an Experimental RFC
Aug 2018 Submit document on adding Explicit Congestion Notification (ECN) to TCP Control Packets to the IESG for publication as Experimental RFC
Nov 2017 Submit RFC793bis document to the IESG for publication as Internet Standard
Sep 2017 Submit document on a time-based fast loss detection algorithm for TCP to the IESG for publication as an Experimental RFC
Aug 2016 Submit specification of more accurate ECN feedback in TCP to the IESG for publication as an Experimental RFC
May 2016 Submit document on Retransmission Timeout Considerations as Best Current Practice RFC
Done Submit document on CUBIC congestion control to the IESG for publication as Informational RFC
Done Submit document on Datacenter TCP (DCTCP) to the IESG for publication as Informational RFC
Aug 2015 Submit document on a TCP Extended Data Offset Option to the IESG as a Proposed Standard RFC
Done Submit document obsoleting undeployed TCP extensions to the IESG for publication as an Informational RFC
Done Submit revision of TCP roadmap (RFC 4614) to the IESG for publication as an Informational RFC
Done Submit document on an analysis of more detailed ECN feedback in TCP to the IESG for publication as an Informational RFC
Done Submit document on TCP support for rate-limited traffic for publication (status decided as earlier milestone)
Done Submit document on restarting the RTO timer to the IESG for publication as an Experimental RFC