The IP over ATM Mailing List Archive by date

[gja@thumper.bellcore.com]

Narayanan,

>>I'm sorry I didn't make my point sufficiently clear. My concern
>>was how we're going to deal with "passive" hosts - i.e., hosts
>>that just sit there waiting for others to contact them, and have
>>no traffic to send themselves. In this case, the host would never send 
>>an ARP_REQUEST to the ATMARP server, so the server would never update
>>its table entry. Other hosts that wished to contact the passive host
>>would thus end up getting ARP_NAKS from the server.

You describe a valid problem, but an explicit solution is not
particularly tricky. As Mark's implied, we simply arrange for
the ARP clients to issue some form of ATMARP message to the ARP
Server to 'pre-register' themselves.

Another solution might be this:

	- Assume (dangerous, I know :) that a LIS host is always
	  configured with a route (perhaps default route) to an
	  IP router attached to the LIS.
	- A LIS host's ARP entity issues an ARP Request whenever a new
	  gateway is added to the host's routing table. (messy hack?)

So, even a host that aims to be passive (as far as not initiating IP
activity) would engage in some ARPing activity while starting up.
This may be sufficient to pre-register the host with the ARP Server. 
(Of course, this falls apart for completely isolated LISs. Hmmm.....)

An explicit pre-register message from the ARP client seems an better
all round solution. It is also likely to fit in with the IPmc model
that I'm hoping to have re-drafted rsn.

gja
---
Grenville Armitage, Member of Technical Staff, Bellcore.
MRE 2P-340, 445 South Street, Morristown, NJ, 07960-6438, USA
Internet: gja@thumper.bellcore.com     Voice: +1 201 829 2635