HSRP hardware limitation on catalyst 4500-X

rherve · ‎10-21-2013

Hi,

Is there anyone who could give me the hardware limit on the maximum number of HSRP group that you can use simultaneously on a Catalyst 4500-x?

Is it 256 ?

If someone can do the test? Unfortunately I don't have a 4500-x to make the test

Regards.

branfarm1 · ‎10-21-2013

Still 256 ---

4500X-1(config-if)#standby ?

<0-255> group number

authentication Authentication

bfd Enable HSRP BFD

delay HSRP initialisation delay

follow Name of HSRP group to follow

ip Enable HSRP IPv4 and set the virtual IP address

ipv6 Enable HSRP IPv6

mac-address Virtual MAC address

mac-refresh Refresh MAC cache on switch by periodically sending packet

from virtual mac address

name Redundancy name string

preempt Overthrow lower priority Active routers

priority Priority level

redirect Configure sending of ICMP Redirect messages with an HSRP

virtual IP address as the gateway IP address

timers Hello and hold timers

track Priority tracking

use-bia HSRP uses interface's burned in address

version HSRP version

Steve Fuller · ‎10-21-2013

Can you clarify what you mean "hardware limit on the maximum number of HSRP group"?

The limit of 256 is an HSRP version 1 protocol limit with respect to the range that the HSRP group can be set to. If you look at RFC 2281 Cisco HSRP, you'll see this specified in section 5.1:

Group: 1 octet

This field identifies the standby group. For Token Ring, values

between 0 and 2 inclusive are valid. For other media values

between 0 and 255 inclusive are valid.

If you use HSRP version 2 the HSRP group number range is 0-4095 and once you've specified standby version 2 within the interface vlan context then the extended range can be seen.

So if you want to use more than 256 HSRP groups on a router then HSRP version 2 is the way to go. The only thing to be mindful of then is how that number of groups may affect the CPU utilisation of the router.

Regards

rherve · ‎10-22-2013

Hi,

Thank you for your answers, but I am not sure because I had test these commands on a 3750X and I also <0-255> group number.

example:

3750x(config-if)#standby ?

<0-255> group number

authentication Authentication

delay HSRP initialisation delay

follow Name of HSRP group to follow

ip Enable HSRP IPv4 and set the virtual IP address

mac-refresh Refresh MAC cache on switch by periodically sending packet

from virtual mac address

name Redundancy name string

preempt Overthrow lower priority Active routers

priority Priority level

redirect Configure sending of ICMP Redirect messages with an HSRP

virtual IP address as the gateway IP address

timers Hello and hold timers

track Priority tracking

version HSRP version

This means that I can configure 256 id en hsrp version 1 from 0 et 255.

But when I create more than 32 vlans configured with HSRP protocol then I reach the maximum hardware limit.

I receive the following message:

3750x(config-if)#standby ip 10.10.34.254

%Platform already has maximum FHRP groups configured

The real test would be configured on the 4500-X up to 256 vlans with the HSRP config for these 256 vlans to see if the message is identical to 3750x? If the hardware limit are reach

Can you test it for me please ?

Thanks

Regards

Steve Fuller · ‎10-22-2013

Hi,

I'd rather have found some official documentation from Cisco that stated the limit they support, but in the absence of that I've tested it and it would seem there's no obvious limit as you found with the Catalyst 3750.

In the output of the show version you can see there are now 256 Virtual Ethernet Interfaces created, the show standby internal summary shows 247 configured interfaces and there's also a snip of the show standby brief.

There are only 247 interfaces seen in show standby internal summary as I already had some interfaces with GLBP running so couldn't configure those interfaces with HSRP. Note also that they show as INIT as I only configured one device.

4516x-1#sh ver

Cisco IOS Software, IOS-XE Software, Catalyst 4500 L3 Switch Software (cat4500e-UNIVERSALK9-M), Version 03.05.00.E RELEASE SOFTWARE (fc3)

Technical Support: http://www.cisco.com/techsupport

Compiled Tue 27-Aug-13 14:56 by prod_rel_team

[..]

cisco WS-C4500X-16 (MPC8572) processor (revision 4) with 4194304K bytes of physical memory.

Processor board ID JAE164800HF

MPC8572 CPU at 1.5GHz, Cisco Catalyst 4500X

Last reset from Reload

256 Virtual Ethernet interfaces

16 Ten Gigabit Ethernet interfaces

511K bytes of non-volatile configuration memory.

4516x-1#sh standby internal summary

[..]

Configured 0 247 0 0 0 1 1

Learnt 0 0 0 0 0 0 0

4516x-1#sh stand brief

P indicates configured to preempt.

|

Interface Grp Pri P State Active Standby Virtual IP

Vl2 2 100 Init unknown unknown 3.3.2.1

Vl3 3 100 Init unknown unknown 3.3.3.1

Vl4 4 100 Init unknown unknown 3.3.4.1

Vl5 5 100 Init unknown unknown 3.3.5.1

Vl6 6 100 Init unknown unknown 3.3.6.1

[..]

Vl250 250 100 Init unknown unknown 3.3.250.1

Vl251 251 100 Init unknown unknown 3.3.251.1

Vl252 252 100 Init unknown unknown 3.3.252.1

Vl253 253 100 Init unknown unknown 3.3.253.1

Vl254 254 100 Init unknown unknown 3.3.254.1

Vl255 255 100 Init unknown unknown 3.3.255.1

Regards