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Redundant 6509 MSFC

Currently I am doing some work for a university that has a 6509 with redundant MSFCs. I am thinking about suggesting to them to buy another 6509 chassis and have them move the redundant 6509 SUP/MSFC to the new chassis. Is there a licensing issue? If so, how to rectify it?

Thanks in advance for your help.....


Re: Redundant 6509 MSFC

Shouldn't be any problems with that as far as licensing. You might have some restrictions from your leasing company or something like that.

However, should one of them fail in either switch, you will lose that switch and everything attached. Its ok if the other switch is to be configured to provide redundacy to the first, but if not you might consider having dual-MSFC's in both.


Re: Redundant 6509 MSFC

Depends on how they're using the 6500 with the dual Sup modules.

For example, if it's a solitary, dedicated core switch, then a second chassis could be useful in building a redundant core. Of course, you'd have to factor in the cost of giving each attached distribution or access switch a second, redundant, link to the other chassis. But once you're set up this way, and configured for HSRP, STP UplinkFast, etc., you could take down one core chassis for maintenance virtually without anyone noticing.

If you have line cards in the original chassis, for example 48-port 10/100 to handle servers and/or desktop workstation computers, then the switch is not truly a core-only switch. Pulling out the redundant Sup module for installation in a separate chassis increases the risk that devices plugged only into that chassis will be cut off if/when the chassis is rebooted or fails.

Two Cat6500s at the core with dist./access line cards installed, are best served by dual Sup modules in each for ultra-high-availability. But it isn't cheap.

If you can remove the line cards and replace their functionality with dual-Gig-connected 48-port standalone switches, getting the chassis to be a core-only device, then redundant chassis with a single Sup in each makes a lot of sense. The standalone 48-port 10/100 switches are less expensive than the chassis-integrated 48-port 10/100 line cards.

If you need high-density Gigabit, though, for example to support a server farm, then breaking it out of the chassis to a separate switch doesn't make sense: the standalone switch uplinks become a bottleneck.

Hope this helps.

EDITED TO ADD: I remember that Cisco used to offer a second Sup module in the same chassis for 50% of the price of the first Sup module, in order to provide redundancy. But buying two chassis with a single Sup module in each, you had to pay full price for each Sup module. I think there was an IOS licensing issue involved: two Sups in same chassis were assumed to be backing each other up and running as one IOS device, so only one license was needed. Two separate chassis, each Sup would be functioning as an independent IOS device, so two licenses were required.

This is a good question. I'll be looking into it further with my local Cisco office: I have a customer who wants to break out a dual chassis dual Sup configuration to four chassis single Sup in each, all four chassis to be core use only. Will let you all know what I hear from them.