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Core Equipment Redundancy - 6509 with Dual MSFC's

Hello. Looking for some advice and wasn't sure which forum was a best fit for this question.

I am in an environment in which all of our core routing\switching is in one basket with a 6509 running CATOS 6.3(1) and two MSFC2 modules running IOS 12.1(7a)E1

The chassis also has two WS-K6K-SUP1A-2GE Supervisor Blades, two WS-X6408A-GBIC ethernet gig fiber blades, one WS-X6348-RJ45 Ethernet Blade, and two WS-X6182-2PA FlexWAN modules (in use for a channelized DS3 circuit and one point to point T1).

In any case, to make a long story short, while we're confident that we have some redundancy with two Supervisor Modules and two MSFC2 blades, there are some arguments that we still have everything in one box. We've been looking at our redundancy for some time now, and a recent multicast issue some time back that literally took our MSFC CPU's to their knees, impacting all of our slower links (most of our T1's coming in on the channelized DS3), really brought the topic back to life again. While we resolved the multicast issue, we started asking some questions regarding the wisdom of our core routing\switching in one chassis without any redundancy other than internal to the chassis.

Some of the options floated out there include:

- Purchasing a second 6509 with similar configuration and splitting up the services between the two. Problem with this is going to be cost.

- Purchase a second independent L3 switch and Router to be used for redundancy purposes.

- Replace the 6509 and MSFC's with dedicated switching and routing hardware

- Dedicate the 6509 to core layer 3 switching and move the serial services (channelized DS3, p2p T1's, etc.) off to a dedicated router. In this scenario, if we lose core switching, at least our serial links are all still up and vice versa.

I won't drag this on any more. Would like some advice from anyone who cares to share it.

Thanks in advance.


Chris Thompson

Systems Engineer II

Stanislaus County - SBT

Collin Clark


Take a look at the Design Guides, they are very useful, especially in designing redundancy.

Hope that helps.

Rupesh Kashyap

You have to purchase a new switch of same model. Configure HSRP & use Interface tracking facility in that.

I would move the DS3 card to a dedicated 7200VXR router and add a second 6500 chassis. You can split the sups to save some money. It sounds as if you have a calapsed core design (no dedicated distribution layer) so I would used HSRP for gateway redundancy yo the access VLANS.

For multicast, setup dual redundant RPs on each 6500 with MSDP and sparse mode. Search for the campus multicast design docs.

This would still have a single point of failure for your WAN links but it would be a step in the right direction.