The Routing Over Large Clouds Mailing List Archive by date

[Andrew Smith <asmith@baynetworks.com>]

> From owner-rolc@nexen.com Fri Jul  7 12:56:48 1995
> To: James Luciani <luciani@nexen.com>
> Cc: Bruce Cole <bcole@cisco.com>, rolc@nexen.com, bcole@cisco.com
> Subject: Re: NHRP protocol modifications and clarifications 
> Date: Fri, 07 Jul 1995 12:33:45 -0700
> From: Bruce Cole <bcole@cisco.com>

Bruce,

> > What about the case when you have 2 or more NHCs which are co-resident with 
> > their NHS?  You can't figure out for whom the packet was sent in this case 
> > without burdening all NHCs to check to their database.
> 
> I don't think I understand the need for multiple distinct clients in an NBMA
> station (where the clients share the same IP address and interface).

There is an important analogy here with LANE: LANE allows a client to use 
multiple ATM addresses to represent the same MAC destination (for very good 
implementation reasons which I won't go into now - ask Norm). This works because
the server is neither allowed nor required to cache these bindings and answer
queries on behalf of the client. NHRP uses a different model: the server must
caches all bindings and the client never gets to respond to any queries.
However, NHRP also precludes multiple clients from registering as the same
IP address: therefore NHRP cannot support an implementation which would
prefer to use multiple separate incoming VCCs into the same IP destination.

This is a non-feature, not a bug, and it does complicate some implementations.
 
> I would clarify "own identify".  For the purposes of this section, I believe
> it means the set of IP addresses and NBMA addresses assigned to the NHS
> station itself.

I would also add the clarification that these are all 1:1 mappings and that all
IP and ATM addresses are unique across the whole cloud.


Andrew


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