This isn't quite right.  See comments below.

"Kim Graham"  wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> This brings up a question.  I understand that after the initial "hi I will
> be handling your requests please use me as your destination mac address".
> (Router talking to client).
>
> But what happens when the initial router fails and HSRP kicks in? After an
> unreachable, would ClientA send out an arp or would RouterB initiate the
> arping to re-establish connections to any client that was using RouterA
> after it noticed that RouterA was not responding?
>
> Scenario:
>
>
> ClientA ----- RouterA/B(HSRP) ------ ClientB
>
> ClientA  sends a packet to ClientB
> ClientA  talks to the Virtual RouterA/B -- RouterA/B sends to ClientB
> RouterA/B tells ClientA -- RouterA will be handling your requests.

Router A never tells Client A that "Router A will be handling your
requests".  As you mentioned, Client A talks to the Virtual Router via the
Virtual IP address which it ARPs to find the Virtual MAC.  Client A never
knows which of the HSRP routers is "intercepting" and processing it's
requests....  When Client A sends a frame to the Virtual MAC to go out of
it's gateway, both Router A and Router B "hear" the packet, but only the
HSRP Active router will process it.  So if, the janitor steps in and unplugs
Router A, then after Router B misses enough Hello packets from Router A, it
declares itself the Active HSRP router for that HSRP group, and at that
point it starts to process the information sent to the Virtual IP/Virtual
MAC.  This is all transparent to the end clients, Client A in this example.
So as far as Client A knows, it's still sending traffic to the Virtual IP
via the Virtual MAC address it has in its ARP cache.....

HTH,
Mike W.




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