Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!CISCO.COM!forster
From: forster@CISCO.COM (Jim Forster)
Newsgroups: comp.protocols.iso
Subject: Re: CONS question
Message-ID: <8912050312.AA25497@ucbvax.Berkeley.EDU>
Date: 4 Dec 89 19:05:42 GMT
References: <8912011020.AA12134@jerry.inria.fr>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 27

Last week Christian was discussing solutions for proving CONS over
Ethernets and other LANs.  He mentioned the orthodox way to do this, and
a popular way.

>> The popular line is to stack a small convergence protocol over TCP-IP,
>> e.g. in order to provide packet delimitation within a byte stream. Here
>> again, one can use NSAP addressing, and consider the TCP-IP <host
>> address + port> as a 48 bits SNPA. This is implemented in ISODE, and
>> also in the EAN X.400 service, as well as by CISCO. Problem here is the
>> lack of an agreed convergence protocol (RFC?).

I was a bit confused because we at cisco do not do anything in particular
with ISODE.  After discussing it with Christian, I now understand what he
meant, and think the clarification might be of interest to others.

cisco does not do anything with ISODE.  We can, however, however, switch
X.25 calls through our routers.  If the source & destination of the X.25
call are not on the same router the X.25 PLP is sent inside a TCP
connection to the remote router, across an arbitrary internet.  This
approach is similar to ISODE, in that an ISO protocol (in this case 1984
X.25, which approximates CONS) is carried in a TCP stream.  At this point
we have not done anything, such as a library, or documenting the protocol,
to allow Ethernet-based workstations to be endpoints in this scheme.


  Jim Forster
  cisco Systems


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