vlan trunking to a 6509 switch

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Apr 15th, 2007
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I am have a 3845 router and two 6509 switches. The router is the data and the voice gateway. For voice the router is running SRST with a remote call manager.

I would like to get the router connected to both switches at the same time to provide redundancy in case one switch dies. The two switches are running HSRP.

I tried to run dot1q from the router to the switch and gave each sub interface on the router an IP unnumbered address to a loopback interface.

This did not work as I could not pass any traffic on either vlan.

Any help would be appreciated.


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chrihussey Mon, 04/16/2007 - 03:28
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The 3845 router has two GigE interfaces.

Why not connect the 3845 to each of the 6500s via /30 routed links?

srosenthal Mon, 04/16/2007 - 06:20
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The reason for not using seperate GigE ports is that I need to pass both the Data subnet and the voice subnet.

Currenty I am using one GigE for data and the other for Voice with both connected to the same switch.

I was trying to trunk both subnets to the switches over each GigE port. I thought by using the Ipunumbered that I could avoid having to add another subnet. Also, using another subnet would keep phones from registering.


chrihussey Mon, 04/16/2007 - 07:36
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I understand better now, and think what you are trying to do may be accomplished using IRB with BVI interfaces. Nothing I'd like to do.

Do the 6500s have routing capability (MSFCs)?

If so, have the 6500s run HSRP and be the default gateway for the voice and data VLANs.

Implement the /30s to the 3845 with routing and define a loopback IP on the router to be the SRST address for the phones. They will register to this just as well.

I'm not sure if this helps you and I may be missing something, but I think it is the best way to go.

mahmoodmkl Mon, 04/16/2007 - 03:33
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As the other poster suggested u need to have a redundant connection from u r router to the two switches.

But i am afraid that the router will not allow u to define the ip address in the same subnet two times.





chrihussey Mon, 04/16/2007 - 03:41
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If I wasn't clear, separate L3 /30 links.

For example:

3845 G0/0 /30 --> 6509 #1 /30

3845 G0/1 /30 --> 6509 #2 /30

With routing enabled across these links and between the 6500s, if one of the switches fails, then the other will still have the path to to router.


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