Need opinions regarding redundancy and route on a stick

[rainman]

Hello,

I have a situation I am troubleshooting where we have the following scenario:

[router] --- dot1q trunk--- [switch] -- [other switches]

Basically I am doing router on a stick (I have sub-interfaces on the router's interface facing the 1st switch. The issue I am having is if we have a faulty line-card on the router (say a GEIP fails), we want to have a second trunk link from the router to the switch cluster/matrix. Aside from getting it physically connected, if our primary GIG card on the router failed, we would still have that second GIG up (to another card, for card level redundancy), but it would require manual intervention with moving the sub-interfaces off the 1 gig port and onto the other.

Is there an easier way of doing this (such as a way to place that second GIG port into a standby group or something?) I am familiar with doing HSRP but usually that requires multiple routers (is it possible to do HSRP between linecards without running into the overlapping IP subnet issue?)


Any thoughts/suggestions?


Thank you,

Rainman

 

[brianinms]

You can plug both gig ports into the switch and configure a port group on the router. Ideally you would have a layer 3 switch instead of router on a stick.

 

[rainman]

brianinms - Thanks for your reply. What if both GIG ports went to separate switches tho (both dot1Q trunk links within same switch cluster). Also what about the possibility of doing bridging (IRB)? How does IRB react to dot1Q trunks, and can a BVI interface accomodate for sub-interfaces?


-Rainman

 

[brianinms]

Stack meaning 3750's?

 

[rainman]

No, when I say "stack" i merely mean a "group of switches connected together and the links are configured as trunks"... definately not using Cisco stacking technology..

Any other thoughts? Will a port-group work on this instance if both links going from the router to separate switches in the trunk/group/cluster? I can see it working if Router A has 2 trunk links to switch A and put both in a port-channel bundle but what if those links both terminate on router A but go to switch A and B?

I guess my issue i'm running into is the pure limitation of router on a stick! (and why people dont do it)... I'd personally rather have multiple routers/switches per site and do HSRP but need to make the most out of this current situation....


-Rainman