11-09-2011 01:42 PM - edited 03-07-2019 03:18 AM
Currently we have a 6513 core (running IOS and doing limited routing) with VLAN Trunking to about a dozen 3560 edge switches, with various VLANs going to each of the edge switches. All works well. We are downsizing and replacing the 6513 core with a 3750G stack. We have the stack up and running in the lab, and want to slowly (as we move floors) migrate all of the edge switching to the 3750 stack.
The plan is to connect the 3750 stack to the 6513, then slowly migrate the edge switches to the stack (from the 6513). I would like to put in place 4 x 1GB trunk links between the 6513 and the 3750 stack before I start moving edge switches to ensure adequate bandwidth. Once all of the edge switches are on the new 3750 stack, I will start to decommission the 6513.
What is the best way to configure the links between the cores (old 6513 and new 3750 stack)? I can easily get the edge switches configured to the 3750, but am worried about the core links. I really want to avoid having to perform an all-at-once cutover of the cores. Another question is when do I try and migrate the VTP server role from the 6513 to the 3750 stack? I could simply make everything transparent, and ditch server-based VTP, as we rarely change or creat VLANs.
11-09-2011 01:58 PM
Configure crosstack etherchannel on the 3750 . Just do a search on crosstack etherchannel and it will show you how to set it up , uses LACP for the etherchannel. If you dont make a lot of changes then transparent is probably a good idea.
11-09-2011 02:16 PM
Thanks for the quick response. I was starting down that road, but wanted to make sure it would allow my the ability once configured to hang the edge switches off of the 3750 stack without any issues. I'll start the configuration tomorrow, and try a spare edge switch in the lab. I also will test the ability to have links fail for failover.
11-14-2011 09:12 PM
Thanks, this worked perfectly, as did the failover test. The only open task is to make the new 3750 stack a VTP server (currently a client). Want to change during off hours in case something odd happens and wipes out the VTP configuration across all of the switches. I assume that this should not be an issue as long as the revision number match between the current single-server and the client I am "promoting".
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