Subject: [VRRP] Virtual MAC Address "Non-Support"

From: John Border <[email-masked]>
Date: Mon, 30 Sep 2002 11:16:39 -0400

I have been asked to add VRRP support into an existing hardware platform
which cannot support the use of a VRRP virtual MAC address.  Since support for
the virtual MAC address has quite a few MUST requirements associated with it
in RFC 2338, I will not be able to claim even conditional compliance with the
standard.  But, it looks to me like I can still make it work, albeit at the
cost of being very dependent upon the use of the gratuitous ARPs (and ARP
cache timeouts when the gratuitous ARPs don't work) re the speed at which a
redundancy switch "takes effect".  (But, since the target environment for the
router is very limited, this is probably acceptable.)
 
    Actually, I am 100% sure I can make it work when the two routers making up
the virtual router are both my implementation.  But, I was curious whether
there is any implementation experience with a router which does not support
the virtual MAC address being in a virtual router group with another router
which does.  I have read the RFC a few times and the only issue I can see is
whether or not the compliant router will discard a VRRP Advertisement if it
does not have a source address set equal to the virtual router MAC address.
Section 7.1 of RFC 2338 does not say that the receiver must discard an
advertisement if it does not have the virtual MAC address as its source MAC
address.  But, it also doesn't say that it must not.  So, I am curious as to
what routers actually do in the real world...

John
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From: "RamanaReddy venkata kunam" <[email-masked]>
Date: 30 Sep 2002 16:27:38 -0000

hi,
There is no need to drop the advertisement if the source address 
is not
equal to virtual MAC address. The main aim of using virtual MAC 
address
as source address in the advertisement to learn bridges(if any 
in
between Master and standby). If a bridge is present in between a 
master
and backup, the mac entry related virtual mac address times out, 
and
bridge loses the knowlege of virtual mac address router. so it has 
to
send the packets on all the interfaces.
If any points i missed out pls make me clear.

ramana