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Version 5.12.0, 2015-02-26
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TCP Implementation (tcpimpl)
(concluded WG)

Note: The data for concluded WGs is occasionally incorrect.
Name: TCP Implementation
Area:Transport Area (tsv)
State: Concluded
Charter: charter-ietf-tcpimpl-01 (Approved)
Chairs: Mark Allman <>
Vern Paxson <>
Mailing List

Charter for Working Group

The objective of this group is to decide how to best address known
problems in existing implementations of the current TCP standard(s) and
practices. The overall goal is to improve conditions in the existing
Internet by enhancing the quality of current TCP/IP implementations. It
is hoped that both performance and correctness issues can be resolved
by making implementors aware of the problems and their solutions. In
the long term, it is felt that this will provide a reduction in
unnecessary traffic on the network, the rate of connection failures due
to protocol errors, and load on network servers due to time spent
processing both unsuccessful connections and retransmitted data. This
will help to ensure the stability of the global Internet.

Examples of detected problems:

o TCPs that retransmit all unacknowledged data at a single time.
This behavior greatly adds to Internet load, at a time when
the network is already under stress. The combination can
lead to congestion collapse.

o TCPs that misinitialize the congestion window, leading to
potentially enormous bursts of traffic when new connections
begin. Such burstiness can greatly stress Internet routers.

In the BOF, it was generally agreed that problems of this class need
to be fixed.


The scope of this group must be carefully defined in order to ensure
timely progress. To this end, TCP issues that still remain areas of
research are considered out of scope for the WG. For example new
improvements in congestion control algorithms are not within the WG
scope. The WG will solicit input from the End-To-End research group of
the IRTF on questions of whether a TCP implementation issue is
considered research.

The major objectives of this group will be to :

Produce a compilation of known problems and their solutions. This will
raise awareness of these issues.

Determine if any problems found are the result of ambiguities in the
TCP specification. If necessary, produce a document which clarifies
the specification.

Catalog existing TCP test suites, diagnostic tools, testing
organizations, and procedures that can be used by implementors to
improve their code, and produce a document enumerating them.


Working group formation. Decide on document editors.
Define schedule for producing the test suite catalog
First Internet-Draft of problems and fixes, and very rough first draft of catalogue of test suites.
Issue revised Internet-Draft documents.
Cut-off for determining whether clarification document is needed. If necessary, have interim meeting to focus effort on clarification document.
Submit Internet-Draft of problems and fixes to IESG for publication as an RFC.
Submit Internet-Draft of test catalogue to IESG for publication as an RFC.
Submit Internet-Draft clarifying RFCs 793, 1122, and 1323 to IESG for publication as an RFC.
Submit Internet-Draft on increasing TCP's initial window size for publication as an experimental RFC.
Submit Internet-Draft of test catalogue to IESG for consideration as an informational RFC.
Submit I-Ds in support of larger initial window I-D to IESG for consideration as an Informational RFCs
Begin work on revisions to RFC 2001.
Begin work on a security problems document (to be much like the known problems I-D currently being developed).
Submit revised version of problems and fixes as an Internet-Draft.
Submit problems and fixes document to IESG for consideration as an Informational RFC.
Submit revision of RFC 2001 to IESG for publication as Proposed Standard. Most likely this will include changes to the initial window, reflecting experienced gained with the Experimental initial window RFC. May include changes to restart-after-idle behavior
submit Internet-Draft on problems with Path MTU discovery to IESG for publication as an Informational RFC
Conclude Working Group