At 10:19 AM 6/23/02, Kim Graham wrote: >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).
Well, there's not really an initial "hi," although I like the literary sound of that. The client ARPs for its default gateway and the router answers. The client has been configured with the virtual IP address for the gateway. The active router responds with the virtual MAC address in the ARP reply. >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? It's completely transparent to the client. The standby router takes over and forwards packets addressed to the virtual MAC address. >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. >RouterA/B tells ClientB -- RouterA will be handling your requests to ClientA >ClientA then sends more packets to ClientB via RouterA. >ClientB responds to ClientA via RouterA. > >Janitor comes in and accidentally unplugs RouterA's power cord. > >ClientA now has to re-establish a connection with ClientB. > >I have seen the above scenario happen in a failover test when implementing a >new core but did not have a bug in my ear to watch the MAC addresses. It >has my curiosity perked. > >In theory I beleive RouterB would re-establish communication after a failed >"hi are you there packet to RouterA". I will have to wait until a lab is >set up to play out the scenario. > >Kim ________________________ Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=47261&t=47177 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
