Replace Core Switch

[Mokhalil82]

Hi 

I am wondering how most people go about this. If I was replacing a core switch, how would you guys recommend I migrate the config over. SSo would you

1) connect the new core to the old core and then take a phased approach by migrating layer 2 then layer 3

OR

2) copy configs over to the new core and then patch everything over

Not done this before so checking how people would do it, I understand each has it's advantages and disadvantages

[Reza Sharifi]

Hi,

If you have a layer-2 trunk between the old core and the new core, you can migrate all your layer-2 switches to the new core and than have a maintenance window to move all layer-3 links (if any) and SVIs from the old core to the new core.  If the old and new switch platforms are the same (or almost the same) there should not be many differences between configs.  So you can copy from the old switch to notepad, make the changes and than paste to the new switch.

HTH
 

[Mokhalil82]

Thanks Reza, My only concern really is that I have QOS and multicasting configs as well so wasn't sure at what stage would I migrate those. This is to be done OOH in one day so I was thinking of doing it all in one go and trying to mirror the QOS configs, although some WRR configs are not being accepted on the new core

[Reza Sharifi · Accepted solution]

Correct and a very good point. So one thing that has completely changed with newer Sups (2T) is the QOS architecture.  Most commands have been changed and so for the QOS you need to do some homework/research to be able to convert it to the new system.  If QOS is not a very important part of this migration and can wait then you can always add that later.  As for multicast, the config should be the same between the 2 switches.

You do need a long outage window if you have a lot of configs to move over, but I would be concern with moving the SVIs first, than any layer-3 device, firewall, WAN routers, etc.. and than do the multicast, qos, etc..

Get the basic config up and running, so your users have access to Internet, internal resources, servers, etc..and than you can always add to it.

HTH

[Mokhalil82]

Thanks Reza, a very helpful answer