Configure SVL on Cisco Catalyst 9606 Chassis with Dual Supervisors

Hello Craig Beck

We're currently in the planning phase of migrating CAT 6807-XL switches (which are set up as a collapsed core and VSS) to CAT 9609R switches.  6807 configures all SVIs, and  IDF access switches have L2 Port channels to Cores. 6807 does all the routing to WAN and Internet. Default route to Edge firewall.

How would you recommend approaching this? 

What would be the optimal migration strategy to ensure minimal downtime?

I'd trunk all L2 across to the 9600s from the 6807s. Move the SVIs and other L3 to the 9600s and move the physical links over once tested. That should leave the 6807 with nothing connected to it.

Hello Dear Craig Beck,

I've outlined the steps below and would be grateful for your input.

1- Since the 6807s are set up in VSS mode, disconnect 6800-Core2 and then remove it from the rack

2- Position the 9600-Core2 within the same rack.

3- Setup the trunk between 6800-Core2 and 9606-Core2 and allow all VLANs

4- Move the SVIs to 9606-Core 2. Should we be shifting SVIs incrementally, configure OSPF routing to enable subnets on 9606-Core 2 to access the internet and data center via 6807-Core 1.

I'm uncertain about the physical links. IDF Access Switches currently have port channels connected to the 6807s. How can we transition them to 9606-Core 2 first?

Due to critical operations, we need minimal downtime.

Everything good up to 4.

Move ALL L3, including SVIs to the 9606. That way you don't need a routing protocol between the 9606 and the 6807. It keeps it simple.

If you have port-channels you'll need to break them. You can then move the 2nd leg of each link to the 9606. Make the 9606 the STP root for all VLANs.

Move ALL L3, including SVIs to the 9606. That way you don't need a routing protocol between the 9606 and the 6807. It keeps it simple. 

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If we move the SVIs incrementally, then routing protocol will be necessary.

If you have port-channels you'll need to break them. You can then move the 2nd leg of each link to the 9606. Make the 9606 the STP root for all VLANs. 

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Do we need to break them on the Access Switch or the 6807 Cores?

If we move the SVIs incrementally, then routing protocol will be necessary.

 Yes, which is why I said move them all at the same time. If you do it piecemeal, you'll spend more time trying to work out why things don't work than simply moving everything over in one go. 

Do we need to break them on the Access Switch or the 6807 Cores?

If you leave primary links connected to the 6807 and also move secondary links to 9606 you will need to break the port-channels at each end. If you move the secondary links to the 9606 and leave the primary links disconnected, you theoretically don't need to break any.

Hello Dear Craig Beck,

I have revised the steps, would be grateful for your input 

1- Since the 6807s are set up in VSS mode, disconnect 6800-Core2 and then remove it from the rack

2- Position the 9600-Core2 within the same rack.

3- Setup the trunk between 6800-Core2 and 9606-Core2 and allow all VLANs.

4- Move ALL SVIs to the 9606 including the default route to edge firewalls.

Configure SVIs on 9606 and keep it shut.

Shutdown all SVIs on 6807
int range vlan 2,5,6,7,9, 10-50
shut

Unshut all SVIs on 9606
int range vlan 2,5,6,7,9, 10-50
no shut

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5- Make the 9606 as the root bridge for all VLANs using this command. This will trigger STP convergence. 

Will it cause a disruption in the network until STP converged?

spanning-tree vlan 1-4096 root primary

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6- Moving the physical links for some non-critical access to 9606-Core2

7- Without breaking any port-channel on any switch, just shut down the interface on 6807-Core1       connected   to access switch as primary link

8- Connect physical secondary link to 9606-Core2.

Looks good, just need to review 6-8.

For 6, it would be better to move the critical stuff first, as the 9606 is now the primary core. The non-critical stuff can stay on the 6807 for now.

For 7-8 you'd want to physically connect to both the 6807 and the 9606, but leave the 9606 links shutdown. Then when you're ready, just shut on the 6807 and no shut on the 9606.

Thank you, Craig Beck, for your continued support. Your dedication on EE is genuinely valued and appreciated