HSRP behavior during the establishment

[KseniaM]

Hello.

I have a question. I use 2 2600 routers with HSRP v1. I see, that during the speak state both routers are sending packets with the Virtual MAC and not their real MAC. Can it be changed by configuration? Is it the same in HSRP v2? And VRRP (I read that in VRRP it uses only real MACs in the conversation between the routers).

Thank you.

[Julio E. Moisa]

Hi

Yes, you can use the MAC address of the Interface using this command under the HSRP configuration:

interface fa0/0 

standby <id> ........

standby use-bia scope interface

If you execute the following command: show interface fa0/0, you will see the MAC address (bia)

Use Burned-In Address

The use burned-in address (BIA) feature allows HSRP groups to use an interface's burned-in MAC address instead of an HSRP MAC address. Use BIA was first implemented in Cisco IOS release 11.1(8). To configure HSRP to use the BIA, use the standby use-bia [scope interface] command.

The use-bia command was implemented to overcome the limitations of using a functional address for the HSRP MAC address on Token Ring interfaces.

https://www.cisco.com/c/en/us/support/docs/ip/hot-standby-router-protocol-hsrp/9234-hsrpguidetoc.html

Although changing the MAC Address used by HSRP is not usual could have some situations where it is required.

Hope it is useful

:-)

[KseniaM]

Hello.

Thank you. Do you know how would VRRP behave without any specific configuration? And if needed is there such?

Thank you,

[Julio E. Moisa]

Hi

I think VRRP does not have a way to modify the MAC address. To be honest I prefer HSRP instead VRRP. 

:-)

[KseniaM]

Hello.

Thank you very much for the reply and sorry for the delay, but as I don't have an option to choose, I want to know how are the packets sent from beginning in the process of active/standby establishment.

[paul driver]

Hello

It can be changed as stated by Julio, however may i ask why do you wish to negate using the vmac address of the HRSP group?

Are you using  port security on the hrsp pairing to negate multiple mac-address entries or is it some other requirement?

Lastly I would personally tend to choose VRRP over HRSP as not only is preemption is enabled by default its non proprietary so it can be used on other networking platforms , thus its more scalable as a FHRP.

res
Paul

[KseniaM]

Hello.

I don't want to use HSRP, I need and want to use VRRP. I don't you wish to negate using the vmac address of the HRSP group, opposite way around. I want to know if VRRP negotiate only by using real MACs' or as the HSRPv1 default by using VMA by both routers.

Thank you,

[paul driver]

Hello
HRSP uses a default Vmac = 0000.0C07.acXX  with XX=hrsp group number
VRRP use a default Vmac = 0000.5e00.01XX   with  XX=vrrp group number

res
Paul