Re: NHRP v6 - hardware type / address type

Grenville Armitage <gja@thumper.bellcore.com> Wed, 29 November 1995 21:18 UTC

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To: Dave Katz <dkatz@cisco.com>
cc: gja@thumper.bellcore.com, bcole@cisco.com, rolc@nexen.com, luciani@nexen.com
Subject: Re: NHRP v6 - hardware type / address type
In-reply-to: Your message of Wed, 29 Nov 1995 10:23:12 -0800. <199511291823.KAA09300@puli.cisco.com>
Date: Wed, 29 Nov 1995 15:52:52 -0500
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From: Grenville Armitage <gja@thumper.bellcore.com>
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>>The mistake of putting hardware type instead of address type into ARP
>>resulted in no end of ugliness when multimedia bridges came along (which
>>is why FDDI uses the "Ethernet" hardware type).

Can you be clearer on what precipitated the ugliness?

If you're doing cross-media bridging then it hardly matters if you're
using a number space in the nhrp packet that is supposedly media-independent.
If each media use dissimilar address spaces you're stuffed either way,
and need to do address translation (or dont bridge/dont do nhrp across
the boundary).

(Am I'm missing something fundamental here? Are we NHRPing across
NBMA network boundaries where the networks use dissimilar address
types? How exactly is the AFN space going to help here? If anything
I'd have thought in such scenarios the edge NHS might find it
advantageous to have the media type carried within the NHRP messages
it is 'bridging' between NBMA networks.)

>>Pardon my ignorance, but it would be helpful for me if you would explain
>>why the media type is useful information in this case.

I would like to know the converse. Why should media information
be lacking? I dont see the supposed 'ARP mistake' as being
sufficient motive for shying away from this.

gja
_________________________________________________________________________
Grenville Armitage                               gja@thumper.bellcore.com
Bellcore, 445 South St.      http://gump.bellcore.com:8000/~gja/home.html
Morristown, NJ 07960 USA          (voice) +1 201 829 2635 {.. 2504 (fax)}