Re: ARP and NHRP question

[James Watt <[e-mail]>]

Tim Salo writes:

+----------
|Are you saying that an NHRP server and an ATMARP server should co-reside,
|perhaps even share a common database, but support two protocols for
|resolving IP addresses into ATM addresses?
|
|Or, should the "NHRP server be the ATMARP server" in the sense that
|the server and clients support only one protocol for resolving IP
|addresses into ATM addresses, namely the NHPR protocol?
+--------
My thinking was that the former turned into the latter when the last of
the ATMARP clients went away - I didn't really think about the distinction.

From my point of view the end game is definitely the latter case.  When
thinking about how to get from today to there, I had got myself solidly
stuck in backwards compatibility think. Thus I assumed we needed to support
ATMARP at least for a transition period.

But that was just my view of how to deal with the transition.  I think
the key _behavioural_ question is:

    Does an NHRP client have to be an ATMARP client to have shortcuts
    to intra-LIS destinations ?

My vote is NO !! There are two implications:

1)  The NHRP server _must_ have "an interface" to the ATMARP service for
    information interchange and

2) When there is no ATMARP left, the NHRP servers will need a co-ordination
   mechanism (as Andrew pointed out) - however as long as there is ATMARP left
   we can use the ATMARP service to do the co-ordination required for 
   intra-LIS support.

Currently the spec says (Section 2.2 para 3):
     'In addition to NHRP, NHSs ... may support "classical" ARP
      service as well.'

It goes on to say (para 4):
     'This table can be constructed ... through mechanisms outside the
      scope of this document (examples of such mechanisms include ARP...'

It would seem we need to adjust this to reflect point (1) above.

Comments ?
-james
____________________________________________________________________________
James W. Watt,     [e-mail]                   Ph: [phone]
Newbridge Networks 600 March Rd Kanata ON Canada K2K 2E6 FAX:[phone]