Migrating Core switches - please validate my thoughts

[d.hodgson]

Hi folks,

I'm about to embark on a migration from 2 x 4506 core switches (to be decomissioned) to 2 x 6807XL switches. Nothing special here, however I'd like to put down my thoughts to see if you agree with my method...

4506's...

contain SVI's utlizing HSRP for access layer data/voice vlans etc.

Layer 2 between cores

I would say typical classic style setup.

Static routing is used (uuurrrghhh)

6807XL's...

VSS configuration

1. I would connect the 4506's to the 6800 via L2 trunk links (prob 4 x 1GB MEC).

2. Migrate services such as access layer, WAN etc. to the 6807's and any relevant static routes.

3. Change timers on HSRP to msec on 4506's and ensure priority is manually set to something like 200 and 150

4. When it comes time to migrate the SVI's across - create SVI's on 6800, configure HSRP on same group using msec and make priority 250 (this should cause minimal impact when traffic starts using this as the gateway. Remove SVI's from 4506's.

5. Remove HSRP config from SVI and configure interface with HSRP address. (this can be quick copy and paste and saves the interface having to go from being down to up if HSRP was not configured).

What do ya think? Is there an easier way? I've done this a fair few times but now I'd like to engage the community to see what you guys would do? It's always nice to have a fresh pair of eyes :)

thanks

Dave

[Leo Laohoo]

If you've got an opportunity to enable VSS, then you don't really need HSRP.

[roger perkin]

It all depends on the traffic. 

If you can sustain a blip then I would not go to the trouble of the HSRP on the new core, just have the config ready to go on both switches and shut down SVI's on the old and bring up on the new - you might drop a few packets but nothing major. 

I am doing much the same right now migrating a Core/Dist from 6509 over to 6880/6807 running VSS. 

I was going to L3 connect the new Dist to the Old core and also run a L2 into the old Dist to bring in the vlans, users will be routing through new dist to old dist to core in the migration period and then when all switches are migrated to the new dist then move the SVI's over to the new Dist and turn off the old Dist. 

If your traffic can sustain a few packets lost two windows in SecureCRT shut down bring up at the same time works fine. You could get into a mess with the HSRP setup 

Just my thoughts 

Roger