Question about HSRP

nygenxny123 · ‎01-30-2008

I was wondering. We have two ds3's going to the same service provider. One DS3 for one 3845 and the other for the 2nd one.

I believe they are being used for load balancing too.

Should the configs be exaclty the same if these are configured for HSRP?

and..how can i tell if traffic is truly bring load balanced?

Wilson Samuel · ‎01-30-2008

Hi,

Using HSRP to achieve Load Balancing is quite a tough task if not impossible, ofcourse one can get a certain amount of Load Sharing.

You may acheieve the Load Sharing using HSRP by creating two groups of HSRP on the Edge Routers and each one having a group of subnets catered e.g. Router1 may cater all odd subnets and Router2 may cater all even subnets.

Now with this we have to achieve the incoming traffic also to be load balanced / load shared and there is the real trick.

Assuming you have a BGP AS, it becomes difficult to do it manually, we used to do it with the help of F5 Load Balancer and it used to do the job pretty well.

These days Cisco also has a product line to achieve that.

Regards,

Wilson Samuel

Joseph W. Doherty · ‎01-30-2008

As Samuel noted, load balancing via HSRP is difficult.

Other options for outbound balancing, without using other products, include (some if supported on your IOS images) GLBP, OER/PfR, and balancing within the routing configuration of the routers.

"how can i tell if traffic is truly bring load balanced?" Note in/out stats on both your routers DS3 links. Should be close to 50/50 over a day.