Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!usc!ucsd!ucbvax!FTP.COM!jbvb
From: jbvb@FTP.COM (James B. Van Bokkelen)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Question on TCP use of IP TOS
Message-ID: <9101222155.AA22412@ftp.com>
Date: 22 Jan 91 21:55:15 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: jbvb@ftp.com
Organization: The Internet
Lines: 14


    Another way of asking this is "Is TOS somehow negotiated during
    connection establishment, or does each end use what it wants
    independent of the other?"
    
Current practice is to assign a TOS value to a given upper-layer protocol,
and use it for all packets (ack or data) related to that connection.  Thus,
there isn't really any negotiation.  One problem with using different TOS
values for two sides of a connection, or for acks vs. data, is that it
greatly increases the chance of asymmetric routing, which might affect RTT
estimation or even reachability.

James B. VanBokkelen		26 Princess St., Wakefield, MA  01880
FTP Software Inc.		voice: (617) 246-0900  fax: (617) 246-0901