This section explains which interfaces and media HSRP supports, and possible caveats when running HSRP over these media.
Since Cisco IOS Software release 10.0, HSRP functionality has been available on Ethernet, Token Ring and Fiber Distributed Data Interface (FDDI). Fast Ethernet and ATM interfaces are also supported by HSRP.
Virtual LANs (VLANs) allow logical network topologies to overlay the physical switched infrastructure such that any arbitrary collection of LAN ports can be combined into an autonomous user group or community of interest. HSRP VLAN support was added in Cisco IOS release 11.1 for IEEE 802.10 Secure Data Exchange (SDE), and in Cisco IOS release 11.3 for Cisco Inter-Switch Link (ISL).
Several Ethernet (Lance and QUICC) controllers in low-end products can only have a single unicast MAC address in their address filter. On these platforms only a single HSRP group is permitted, and the interface address is changed to the HSRP virtual MAC address when the group becomes Active. If you are using HSRP on routers with multiple interfaces of this type, you should configure each interface with a different HSRP group number.
Note: The Cisco 7200 router also uses the Lance Ethernet controller, but it supports MHSRP in software.
Cisco recommends that you have no more than twenty-four HSRP Ethernet Interface Processors (EIPs) due to the time it takes to update the address filters for HSRP. Having more than twenty-four HSRP EIPs can cause instability and excessive CPU load.
If you have more than twenty-four EIPs, try replacing the EIPs with Versatile Interface Processors (VIPs) and Ethernet port adapters. VIPs have been approved for up to eighty HSRP groups. You can also reduce the number of HSRP groups, and increase the HSRP hello and hold time.
Regards Thanveer "Everybody is genius. But if you judge a fish by its ability to climb a tree, it will live its whole life believing that it is a stupid."
in HSRP V1 the standby group forms the last byte of the Active Router's MAC address:
So this format limits the number of standby groups to 256 (0-255).
There are also platform-specific limitations, unfortunately for your Sup 6L I couldn't find a number.
But from a practical perspective, you don't need at all more than 1 standby group for your scenario. The CAM-tables for MAC address filtering are built per VLAN, so having the same virtual MAC address for the Active Routers in different VLANs shouldn't be a problem.
However, many admins like to use different SG to make the SVI-configs look more consistent; to tell the truth: So do we.
But the only really meaningfull scenario with different SG I can imagine is MHSRP (Multi-Group HSRP), here you can find an example:
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