It is indeed related to the command "use-bia". Here's a section from the doc "Hot Standby Router Protocol Features and Functionality" that was suggested by Daniel:
However, the usebbia command has several disadvantages: - When a router becomes active, the virtual IP address is moved to a different MAC address. The newly active router sends a gratuitous ARP response, but not all host implementations handle the gratuitous ARP correctly. - Proxy ARP breaks when usebbia is configured. A atandby router cannot cover for the lost proxy ARP database of a failed router. - Prior to Cisco IOS release 12.0(3.4)T, only one HSRP group is allowed if usebbia is configured. Thanks guys, Eric ----- Original Message ----- From: "garrett allen" To: Sent: Tuesday, March 18, 2003 6:06 PM Subject: Re: Gratuitous ARP and HSRP [7:65633] > eric, > > i can only comment in a limited way and only based on what i have > read. the lower end cisco products (like the 2500's i've been > deploying in remote offices) can only associate one virtual mac address > to an interface and so can only belong to a single hsrp group. if you > have a need to support more than one hsrp group on an interface one way > around that limitation it is to use the bia of the interface as the > virtual address and to issue a gratuitous arp whenever the interface > takes over - the command is "standby use-bia" i recall. higher end > products don't have the limitation and some end stations don't really > respond well to it. > > i haven't actually used this before for money, so there is the > possibility of being wrong and your mileage may vary will use. but it > should start the ball rolling to hear from others. > > cheers. > garrett > > ----- Original Message ----- > From: ericbrouwers > Date: Tuesday, March 18, 2003 1:24 am > Subject: Gratuitous ARP and HSRP [7:65633] > > > Hello all, > > > > I've read in the CCNP Switching Exam Cert. Guide that a standby > > router that > > becomes active in an HSRP group, sends a gratuitous ARP to update > > the ARP > > cache of the end stations with the new active MAC address... > > > > This is strange, since the same virtual MAC address is used by > > active and > > standby HSRP routers. > > > > However, maybe Cisco's implementation has once been like this, > > because I've > > seen instances in the field that ARP caches contained the real MAC > > instead of > > the virtual MAC address when using HSRP. > > > > Can someone give comments on this? > > > > Thanks, > > > > Eric Brouwers > > [EMAIL PROTECTED] > > Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=65695&t=65633 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
