Re: The Hole in my proposal

Joel Halpern <jhalpern@newbridge.com> Sat, 04 February 1995 04:29 UTC

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Date: Fri, 3 Feb 1995 23:27:09 +0500
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From: Joel Halpern <jhalpern@newbridge.com>
Message-Id: <9502040427.AA02025@lobster.Newbridge.COM>
To: curtis@ans.net, yakov@watson.ibm.com, jwg@mare.att.com
Subject: Re: The Hole in my proposal
Cc: rolc@maelstrom.timeplex.com
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Some people have suggested that BGP has "all of the functionality needed"
for the determination of best paths.

Whether this is a true statement depends on the definitions one uses.

If the scope of the NHRP-like query is all within BGP, there are probably
techniques to use the BGP information to detect relevant routing changes,
and therefore keep the complexity down.

However, if one assumes that the scale will be large enough that aggregation
is likely to occur within the boundaries of the ATM cloud, then even the
BGP advertisements with next hop indication will have compressed out some
of the necessary information.  Thus, de-aggreagtion is needed as part of
the exit selection, not just the address resolution phase.
(I do recognize that the allowance for such aggregation brings back
 some risk of loop formation.  However, as long as we are within a single
 protocol scope, even with aggreagation, I expect safety to be achievable.)

At least we are getting some discussion of these issues.
Thank you,
Joel M. Halpern			jhalpern@newbridge.com
Newbridge Networks Inc.