6506 to 6509 interconnect

Unanswered Question
Jun 11th, 2007

I have 3 cisco switches in 3 closets in the same building. the 6509 has 2 sup720 cards. the 6506 switches each have a sup. 32 card. i plan to interconnect with fiber. should the fiber go from the sp 720 to each 6506 sup card? the 6509 has fiber on slot1/1-4. the 6506 switches only have fiber connectors on the sup32 cards.

I have this problem too.
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Richard Burts Mon, 06/11/2007 - 17:24


There are some significant details that you have not told us that might make a difference in how we answer. In particular you have not told us whether these 3 switches are an isolated stand alone network or do they connect to something else? If so, what, and on what kind of media? And you have not told us what kind of cards are installed in each switch.

But based on what you have provided I would say that from the 6506 switches it certainly makes sense to connect from the sup card to the 6509. If there is no other connectivity from the 6509 then it would make sense to connect from the sup720. And if there is other connectivity then we need some more detail before answering further.



coulbournc Tue, 06/12/2007 - 02:56


The switches are going to be on one network with 2 VLAN's and IP address space of We connect to the internet through a firewall and a T1. All servers connect over twisted pair Ethernet. We do not have any VOIP equipment or fiber based storage devices.

Switch1 (Server room) WS-C6509E

Slot1: WS-X6748-SFP

ports 1-4 have fiber connectors

ports 5-20 have POE jacks

ports 21-48 are not equipped

Slot2: WS-X6148-GE-TX

Slot3: WS-X6148V-GE-TX

Slot4: WS-X6148A-GE-TX

Slot5: WS-SUP720-3B

Slot6: WS-SUP720-3B

Switch2 and Switch3 WS-C6506-E(Closet)

Slot1: WS-X6148V-GE-TX

Slot2: WS-X6148A-GE-TX

Slot5: WS-SUP32-GE-3B


coulbournc Tue, 06/12/2007 - 07:49

I forgot to mention that the WS-SUP32-GE-3B modules in switch 2 and 3 each have fiber coneectors in ports 1 and 2.

nate-miller Tue, 06/12/2007 - 09:57

Ports 1/5 - 1/20 aren't POE jacks- they'll be standard GE interfaces. No POE SFPs exist, as far as I know.

Based on this, all of your fiber connections are SFP based. Make sure that the SFPs you've purchased (SX or LH) match the fiber you have in place between your closets. (SX = Multimode fiber, LH = Single Mode Fiber).

All the SFPs should probably match. Easy way to tell is by the color on the handle- they should all be blue, or all be black.

The easiest way to do this would be to configure 5/1 and 5/2 on each Sup32 as an etherchannel. Configure 1/1-2 and 1/3-4 on the core as an etherchannel. Now you're done.

Another way to do this would be to configure an etherchannel on the core between 1/1 and 5/1 and 1/2 and 5/2. This way if you lose card 1, you still have connectivity. If you lose the Sup in slot 5, you fail over to the second sup and still have connectivity to the closets via card 1.

The SFPs in 1/3 and 1/4 would have to be moved to 5/1 and 5/2, in this case.

Any number of variations is possible, you could use 5/1 + 6/1 and 5/2 + 6/2 if you wanted. Doing it the way I first suggested would theoretically let you add up to two more closets connected fia 6/1 and 6/2 later down the road.

coulbournc Tue, 06/12/2007 - 10:10

You are right about the jacks at location 1/5-20. They are GLC-T transceivers. 1/1-4 are GLC-SX-MM transceivers. I do have multimode fiber connected to the existing ODS Lanblazer switches. I plan to re-use those pairs for the new switches. You have answered my question about how to cable the fiber between the patch panels and switches.

I'm going to go ahead and configure each switch and then test it this weekend during non business hours. The person who ordered this setup left the organization and never told how I was supposed to configure it. The last time I set up switches was in 1997 and it has lasted 10 years. I hope to get 10 years from these as well.




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