HSRP groups

[rajeshk200_2]

Hi,

Since we can configure as many hsrp interfaces with the same HSRP group#.. I wonder when we use multiple group #?

Regards,

Rajesh

[amit-singh]

Hi Rajesh,

You will need multiple group when you want to HSRP load balancing across the 2 routers. The way to acheive is, you can configure even number of Vlan active on one router and odd vlans as standby on this and odd vlans as active on second router and even vlans standby on this. This is the way we can achieve HSRP load-balancing.

For example

on R1, Vlan 1,3,5,7 are active with priority 200 and vlan 2,4,6,8 are standby with priority 100.

On R2, Vlan 1,3,5,7 are standby with priority 100 and vlans 2,4,6,8 are active with priority 200.

This can only be achieved if you use a serate group for each Vlan. Like group 10 for vlan 1, group 20 for vlan 2 and so on....

HTH, Please rate if it does.

-amit singh

[rajeshk200_2]

Amit,

Thanx for the response, if we use same group # for odd and even vlan what will happen ?

will that work or malfunction?

Regards,

Rajesh

[amit-singh]

Hey, that will work but you will not be able to load-balance across HSRP groups as all the vlans are in same group.

So in order to achieve HSRP load-balance traffic accross the 2 gateways you should have Multiple HSRP groups configured.

HTH, Please rate if it does.

-amit singh

[rajeshk200_2]

Amit,

I understood, sorry to ask this again and again

As you said earlier Switch1 is having priority 110 for vlan 1 and 100 for vlan 2.

switch2 is having priority 100 for vlan and 110 for vlan 2.

What I mean to say that switch 1 is gateway for vlan1 and switch2 for vlan 2.....so trafic is balanced and both the switches are utilised.

Regards,

Rajesh

[amit-singh]

Yes, You are right. Remember the Virtual IP of the HSRP will be same on both the L3 switches. Now depending on which group is active on a router, the request will be forwarded to that router and will do the inter-vlan routing.

To take your EG : The traffic for Vlan1 will be send to Switch1 and traffic for Vlan 2 will be send to Switch2 and hence load-balancing will work.

HTH, Please rate if it does.

-amit singh

[ananddiwakar]

Amit, just one doubt in this. Virtual IP for VLAN 1 will be different and Virtual IP for VLAN 2 will be different. So for VLAN 1 if priority is core 1 = 110 and core 2 = 100, then core 1 will forward the traffic. And for VLAN 2, if priority is core 1 = 100 and core 2 = 110, then core 2 will forward the traffic.

Will it work like this or am I thinking on some wrong line

[imranmohd]

Hi

You can areate hsrp group for load balancing between redundant paths.

For example R1 is the primary and R2 is the secondary router for one group.

At the same time you can configure R2 as a primary and R1 as a secondary for another group.

For more reference can go through the link.

http://www.cisco.com/en/US/tech/tk648/tk362/technologies_configuration_example09186a0080094e90.shtml

please rate if it works.