TCP Control Block Interdependence

Document Type Replaced Internet-Draft (individual)
Authors Joseph Touch  , Michael Welzl  , Safiqul Islam 
Last updated 2019-01-04
Replaces draft-welzl-tcpm-tcb-sharing
Replaced by draft-ietf-tcpm-2140bis
Stream (None)
Intended RFC status (None)
Expired & archived
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Stream Stream state (No stream defined)
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IESG IESG state Replaced by draft-ietf-tcpm-2140bis
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


This memo updates and replaces RFC 2140's description of interdependent TCP control blocks, in which part of the TCP state is shared among similar concurrent or consecutive connections. TCP state includes a combination of parameters, such as connection state, current round-trip time estimates, congestion control information, and process information. Most of this state is maintained on a per-connection basis in the TCP Control Block (TCB), but implementations can (and do) share certain TCB information across connections to the same host. Such sharing is intended to improve overall transient transport performance, while maintaining backward-compatibility with existing implementations. The sharing described herein is limited to only the TCB initialization and so has no effect on the long-term behavior of TCP after a connection has been established.


Joseph Touch (
Michael Welzl (
Safiqul Islam (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)