Hi Joe, > -----Original Message----- > From: Joe Touch [mailto:[email protected]] > Sent: Tuesday, May 05, 2015 10:54 AM > To: Templin, Fred L; Xuxiaohu; Donald Eastlake; [email protected] > Cc: [email protected]; [email protected]; [email protected] > Subject: Re: [trill] Fwd: Mail regarding draft-ietf-trill-over-ip > > > > On 5/5/2015 9:39 AM, Templin, Fred L wrote: > > Hi Joe, > .. > >> IP in UDP adds only port numbers and an Internet checksum. > >> > >> That doesn't address fragmentation; if outer fragmentation is assumed, > >> IPv4 needs to be rate-limited to avoid ID collisions and the Internet > >> checksum is insufficient to correct those collisions. > > > > Right - that is why we have GUE. But, when these functions are not > > needed GUE can perform header compression and the result looks > > exactly like IP in UDP. > > That seems impossible.
Not impossible - Tom Herbert provided the solution: http://www.ietf.org/mail-archive/web/int-area/current/msg04593.html > The outer IP header indicates UDP as next-protocol, and GUE based on the > port number. Yes. > You can't then compress the GUE header to nothing. You still need at > least one bit somewhere to indicate "compressed GUE header", and there's > nothing left. False and True. False that you can't compress the GUE header to nothing (you can) and True that there is one bit to indicate "compressed". But, that bit coincides with the direct IP encapsulation header. > And no, I don't think "compressed GUE" qualifies as an independently > useful service that warrants a separate UDP port. Right - there is only one UDP port number (GUE). Thanks - Fred [email protected] > Joe _______________________________________________ Int-area mailing list [email protected] https://www.ietf.org/mailman/listinfo/int-area
