Subject: Gratuitous ARP

From: Jeff Ostermiller <[email-masked]>
Date: Wed, 03 Jun 1998 07:28:08 -0700

Currently we have been envolved with a lot of test of gratuitous ARP at
Lockheed Martin with different switch vendors, NIC manufactures, and
router guys. HP-UX 10.01, 9.0x currently does not support gratuitous
ARP. To get around this situation with HSRP we do not use the burned in
MAC address, but instead the virtual MAC address that the routers
negotiate. This is the same scheme that Bay Networks uses with HSRR,
where you specify the virtual MAC address to work with the Virtual IP
address for that router interface. I though VRRP could do both,
negotiate a virtual or use the burned in address. 
Jeff
--   
Jeff Ostermiller
Lockheed Martin Corporation
GES/Computer Systems Engineering
199 Borton Landing Rd.
MS 137-132
Moorestown, NJ  08057
voice:  609.722.2960
fax:    609.273.5379
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---

From: Acee Lindem <[email-masked]>
Date: Wed, 03 Jun 1998 13:39:35 -0400

Jeff Ostermiller wrote:
> ARP.

There are also some token ring driver implementations that do not support
gratuitous ARP on SRB (Source-Route Bridged) networks in order to avoid 
accepting a sub-optimal SRB bridge/ring path. The solution would be to always 
accept an ARP for a complete ARP entry if there is a MAC address change. 

> To get around this situation with HSRP we do not use the burned in

It is HSRP that has the burned-in address option. However, I think it would
be a good option for VRRP as well given that some of the lower-cost 
LAN chip implementations do not support reception of packets for multiple
MAC addresses without putting the chip in promiscuous mode. 

-- 
Acee