Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!SAGE.ACC.COM!art
From: art@SAGE.ACC.COM
Newsgroups: comp.protocols.tcp-ip
Subject: Re: IP over X.25 (request for info)
Message-ID: <8902050748.AA21026@ucbvax.Berkeley.EDU>
Date: 5 Feb 89 04:56:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 28

>Paul,
>After the VC is established, the first packet over the link is an IP
>packet containing source/destination IP addresses and, probably, a TCP
>SYN packet or a UDP packet. Won't the Source/Dest address in the
>first IP packet be sufficient or have I missed some initialization
>problem on the receiving end?
>
>Vint Cerf

Vint,

Unfortunately, the Source address in the IP packet may have little
relation to the X.121 address at the other end of the VC. If there
is at least one gateway between the local machine and the remote 
machine, the virtual circuit really exists as a logical level 2
connection between the local machine and gateway.  It's probably
better to translate from the X.121 calling address to an associated
IP address.

The IETF Performance Working Group has been working on a paper that
covers, amoung other things, issues around SVC management for IP over
X.25.

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|	Art Berggreen		Advanced Computer Communications	|
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