Date: Wed, 31 May 2000 11:13:46 -0400 (EDT) From: Garrett Wollman <wollman@khavrinen.lcs.mit.edu> To: net@FreeBSD.org Subject: [The IESG: Protocol Action: TCP Processing of the I] Message-ID: <200005311513.LAA33906@khavrinen.lcs.mit.edu>
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A busy day at the IESG, it seems.... ------- start of forwarded message (RFC 934 encapsulation) ------- Message-Id: <200005311210.IAA05749@ietf.org> From: The IESG <iesg-secretary@ietf.org> Sender: scoya@cnri.reston.va.us To: IETF-Announce: ; Cc: RFC Editor <rfc-editor@ISI.EDU> Cc: Internet Architecture Board <iab@ISI.EDU> Subject: Protocol Action: TCP Processing of the IP Precedence Field to Proposed Standard Date: Wed, 31 May 2000 08:10:54 -0400 The IESG has approved the Internet-Draft 'TCP Processing of the IP Precedence Field' <draft-xiao-tcp-prec-03.txt> as a Proposed Standard. This has been reviewed in the IETF but is not the product of an IETF Working Group. The IESG contact persons Allison Mankin and Scott Bradner. Technical Summary This document describes a conflict between TCP (RFC793) and DiffServ (RFC2475) on the use of the three leftmost bits in the TOS octet of an IPv4 header (RFC791). In a network that contains DiffServ capable nodes, such a conflict can cause failures in establishing TCP connections or can cause some established TCP connections to be reset undesirably. This document describes a modification to TCP for resolving the conflict. TCP requires that the precedence (and security parameters) of a connection must remain unchanged during the lifetime of the connection. Therefore, for an established TCP connection with precedence, the receipt of a segment with different precedence indicates an error. The connection must be reset . With the advent of DiffServ, intermediate nodes may modify the Differentiated Services Codepoint (DSCP) of the IP header to indicate the desired Per-hop Behavior (PHB). The DSCP includes the three bits formerly known as the precedence field. Because any modification to those three bits will be considered illegal by endpoints that are precedence-aware, they may cause failures in establishing connections, or may cause established connections to be reset. With this RFC the behavior of TCP is changed to ignore the precedence of all received segments Working Group Summary The working group supported the publication of this document. No issues were raised during IETF Last-Call. Protocol Quality This document has been reviewed for the IESG by Vern Paxson and Scott Bradner. ------- end ------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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