Subject: [Fwd: draft-nair-sip-dhcp-00.txt]

From: Gautam Nair <[email-masked]>
Date: Mon, 07 Feb 2000 14:05:03 -0500

Subject: Re: draft-nair-sip-dhcp-00.txt
From: Henning Schulzrinne <[email-masked]>
To: Bernie Volz <[email-masked]>
Cc: [email-masked], [email-masked]
Date: Mon, 07 Feb 2000 13:55:09 -0500

Bernie Volz wrote:
> 
> Gautam:
> 
> I guess I still don't understand what the advantage of singling out
> this backup server is? Is it somehow special? Is it somehow less
> equal than the others?
> 
> If you wanted to communicate some "preference", why not use a format
> whereby you have a preference value after each IP address in the
> suboption 3 list. That way, you can give your backup server less
> preference. The client logic might thus be arrange the addresses in
> order of preference, for those of equal preference, pick one at
> random. If that doesn't respond, pick another one of the same
> preference or if none left, start with next lower preference and
> so on until the list is exhausted (in which case, restart at the
> beginning or ???).

Indeed, it might be simpler to basically replicate the SRV entry (IP
address, weight and preference, where weight is for randomization and
preference is to distinguish backup from primary servers), with a 16-bit
value for each, again to emulate the SRV record. The current solution is
somewhat simpler. (In that case, we may as well replicate the protocol
identifier as well, to allow selection of UDP vs. TCP...)

The reason for backup servers is that there may well be off-site servers
that serve a number of organizations (similar to the lower-ranked email
servers found today), but that should never be used if the primary
server is available.

[Gautam, please replicate to dchp-v4, since I can't post there.]

-- 
Henning Schulzrinne   http://www.cs.columbia.edu/~hgs