CCIE - Hsrp

Author

Hsrp

hawk2000

2004-03-06, 3:13 am

Hi

I have a few remote site offices connecting back to my HQ router 3745 (with 5 serial connection) running HSRP. These remote sites have redundany link conecting to both routers.

If one of my remote site fails, the backup router should take care of this link i.e backup becomes the active(master).

Here is where i got confused. I know that at anytime, only 1 active router can be active. So when the remote site fails, isnt that , the backup will become active,(because of the serial link fail) now both router become active? what happen to my the other remote sites which are still running fine?

Will HSRP still work for this? any input will be useful.

Thanks hawkie

Yankee

2004-03-06, 10:17 am

I'm not sure I understand the question but even the purpose of the configuration confuses me. If you are paying full price for what I assume are point to point links that connect to a single router at the remote site and two routers at the core, why not let them use both circuits and if one T1 fails the other will handle all the traffic it can.
I must be missing something because it seems you have made a simple configuration overly complicated with nothing gained.

Yankee

darthfeces

2004-03-07, 12:59 am

yeah ... a map would be nice

my crystal ball's in the shop !!!

Mozilla

2004-03-09, 2:34 pm

Use interface tracking.

Greynar

2004-03-09, 3:18 pm

Hawkie, I agree with Yankee, you're trying to over-complicate the design.

Quick and simple (If my crystal ball is working):

Stop using HSRP and read the white paper, it works better for local routing when you are setting up redundant local CAT5/6 connections. If you are using two point-to-point links, set them up with different cost metrics. Depending upon the routing protocol tou are using, you will modify different parameters. The "lower cost" link will always be used, until it goes down, then the "higher cost" link will take over for each remote site. Do that set-up for each remote site at the HQ and remote end, and it will save you a lot of grief.

mosam

2004-03-25, 11:59 am

Yes, I know what you mean.. And to answer your question, this will totally depend on the dynamic protocol you are running between your HQ and remote sites.

If you use interface tracking between the HQ and one of the remote sites, yes, once this remote site fails, the traffic to all other remote sites will be switched to the other router. The only way around this is to,

1) have an umbilical connection between both of your HQ routers to pass traffic updates

2) Tag all incoming remote site routes with a lower preference value (and that will depend on your dynamic protocol used)

This way, if one of the remote site links fails, the HQ traffic going to any of the remote sites will be forwarded to the new active HSRP router, then, this router based on the routing updates its receving from the old HSRP router (which has the failed link connected to), will ALWAYS send the traffic to the old router through the umbilical connection unless its a traffic distant to the failed remote site network, will be forwarded in that case through that site serial backup link.

I hope this is helpful, let me know if you have any other question..

Yankee

2004-03-28, 9:02 am

The answer should not be how to make a convoluted network, but how to design it properly.

Yankee

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