Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!pasteur!ucbvax!ANDREW.CMU.EDU!ddp+
From: ddp+@ANDREW.CMU.EDU (Drew Daniel Perkins)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: BOOTP Extensions
Message-ID: <4XHM34y00UoJA1dgwy@andrew.cmu.edu>
Date: 8 Oct 88 02:43:16 GMT
References: <3875@Portia.Stanford.EDU>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 31

> *Excerpts from ext.in.tcp-ip: 7-Oct-88 Re: BOOTP Extensions RL "Bob"*
> *Morgan@labrea.s (901)*
> 1) ARP caches in hosts and gateways, as BootP clients cycle through
> dynamically assigned addresses;

The ARP caches are expected to timeout faster than the BOOTP server timesout
addresses.  Reasonable ARP implementations should do this, although many ARP
implementations out there are not that reasonable...


>  2) redundancy (that is, can you have a backup dynamic address server?);
Yes, we plan on having redundant servers.  There are a number of possible ways
to do this, and we plan on experimenting a bit to see which would be best.
Possibilites are:
1.  Uncoordinated servers each use a separate range of addresses.  If the
client doesn't use the address assigned by a particular server then it should
time out quickly.
2.  Statically assign or dynamically elect primary/secondary labels for
servers.  The secondary servers could watch to see if the primary dies using a
separate protocol or based on the seconds-since-boot field in the BOOTP
request.  When the primary assigns an address it must also update the
secondaries somehow.  This also brings up the issue of keeping track of dynamic
assignments across crashes.

> 3) multiple subnet service (that is, is the server restricted to
> providing service to clients on its own subnet?).
No the server can serve multiple subnets using the gateway field in the BOOTP
request in order to determine the source subnet.  This does limit you to one
dynamic subnet per cable though.

Drew