Hello Neville,

HSRP should be useless on the new data vlans if they are confined in a single L3 C3750 stack as I would expect on a routed access layer.

You should think of moving the users of old vlans to the new ones in the meanwhile you can keep the HSRP groups on the old vlans.

HSRP is a protocol used within a single IP subnet to emulate a virtual router VIP at both L3 and L2: for the new vlans that are terminated on the stacks there's no chance to configure HSRP on the distribution switches they are not members of these new subnets.

>> since OSPF would take care of providing for link redundancy in the event of switch or link failure ??

this is correct OSPF will provide load-balancing and redundancy towards the distribution switches.

You could revert the reasoning: the HSRP groups are a sign of old Vlans spanning on multiple switches and terminated on distribution switches.

Hope to help

Giuseppe

HSRP provides a virtual gateway, i.e. you would not normally deploy it for router to router communication especially using a dynamic routing protocol such as OSPF.

Within a 3750 stack, the stack can maintain a gateway based on the stack master. If the stack master fails, the gateway IP will migrate to new stack master. So, on the face of it, HSRP would not be needed on the very edge. However, there are several points to note.

First, when a gateway address moves to a new stack master, the MAC can change. (How fast or how "permanent" can be configured, I believe.) This may or may not confuse some hosts, especially since a gratuitous ARP, I believe is issued. If HSRP is used, the virtual MAC would not change.

Second, although rarely needed, I find it convenient to be able to place another router in service and migrate to it as gateway using HSRP while clients are active.

Third, I'm unsure whether the gateway migration feature is faster when the stack master fails using a "native" IP address or with HSRP.

Though u have answer from 2 expert in my opinion.

Just want to add, i have seen HSRP a remedy for first hop gateway failure. So if all the traffic remains inside your network what ever said above is true. U have to just take care of the failure for traffic which leaves ur network.