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From: CERF@A.ISI.EDU
Newsgroups: comp.protocols.tcp-ip
Subject: Re: More on IP over X.25
Message-ID: <[A.ISI.EDU].8-Feb-89.22:02:28.CERF>
Date: 9 Feb 89 03:02:00 GMT
References: <8902061938.AA28037@venera.isi.edu>
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Art,

Why struggle to translate from X.121 to IP if the arriving
internet packet has a source IP address in it...oh,
the source IP address isn't the address of the gateway,
if there was a gateway, but the IP address of the source.
Sorry, that's what I forgot. So you want a way to relay
return traffic by way of the VC on which it was delivered.
Seems to me that return traffic is going to get routed
by the gateway based on the ultimate IP destination address
of the returning traffic. If the IP address of the intermediate
gateway can be mapped to an X.121 address, you could look for
an existing X.25 VC with that destination X.121 address and
put the packet on that - without having to map from X.121 to
IP at any time, yes?

Vint