[e2e] UDP length field
touch at ISI.EDU (Joe Touch) Thu, 25 March 2004 11:59 UTC
From: "touch at ISI.EDU"
Date: Thu, 25 Mar 2004 11:59:43 -0000
Subject: [e2e] UDP length field
References: <200104162243.PAA02146@red.redback.com>
Message-ID: <3ADB906E.79A432E0@isi.edu>
Greg Minshall wrote: > > Joe, > > > 3. in the case where IP options add trailers > > in this case, there is insufficient information in the IP_LEN > > and IP_HLEN fields to determine where the UDP data ends > > foo. if an IP option adds a trailer, it needs to give an indication of how to > find that trailer, which is in "IP land", not "UDP/TCP/whatever land" (note > that in rfc893, "how to find the trailer" is actually in "ethernet land"; that > works, since rfc893 is effectively describing an ethernet option that adds a > trailer). I suspected as much. However, if that information is in a trailer-specific location in IP land, then UDP would have to know about all the possible IP trailers in order to determine the payload length, unless that info were passed explicitly. This way UDP has the information more readily available, and is not dependent on an IP/UDP interface. (it's a thin justification, admittedly - esp. that there was only one trailer spec'd and it's been deprecated). Joe
- [e2e] UDP length field Joe Touch
- [e2e] UDP length field Craig Partridge
- [e2e] UDP length field Greg Minshall
- [e2e] UDP length field Bill Sommerfeld
- [e2e] UDP length field Joe Touch
- [e2e] UDP length field David P. Reed
- [e2e] UDP length field Jonathan Stone
- [e2e] UDP length field Hari Balakrishnan
- [e2e] UDP length field Bill Sommerfeld
- [e2e] UDP length field Joe Touch
- [e2e] UDP length field Craig Partridge
- [e2e] UDP length field Troy DeJongh
- [e2e] UDP length field Mikael Degermark
- [e2e] UDP length field Greg Minshall
- [e2e] UDP length field Steve Deering
- [e2e] UDP length field Luigi Rizzo