Upgrade 6807 Quad-Sup6T VSS from 10Gbit to 40Gbit - how?

[jacob.fredriksson]

Hi everyone!

We have 2 x Catalyst 6807 switches in a Quad-Supervisor VSS setup in which one 10 Gigabit link from each supervisor make current VSL-link between the switches. So in total we have 20 Gbit between the two switches.

The Sup6T supervisors in each 6807 has 2 x 40 Gbit ports. This means we have 4 x 40Gbit ports in each switch to use. We are interested in using these 40Gbit ports to upgrade the VSL-link from 20 Gbit to 80 Gbit.

Is there a way to do this without any downtime or breaking the current VSS or VSL-link?

Could we set up new VSL port-channels to deal with the 40Gbit ports from each side, connect them together while the old 10Gbit links are still up and running? And then remove the 10 Gbit cabling if everything looks okay in CLI.

Any tips?

[balaji.bandi]

Is there any reason behind, why you are not choosing the path to  by adding new links to same port-channel and remove the old links. ? just thought.

Adding and Deleting a VSL Port After the Bootup

At any time, you can add and delete VSL ports from a port-channel to increase the nunber of links in the VSL, to move the port from one port to another, or to remove it from VSL.

Before adding or deleting VSL ports, do the following:

• Ensure all ports are physically connected to the peer switch. The peer port must also be configured for VSL.
• Shutdown the port before configuring VSL. When both ports on the link are configured for VSL, unshut them.
• Spread VSL ports across multiple modules.
• While deleting a port, retain at least one “active” VSL port pair. Else, a dual-active operation could occur.
• To save link flap and high CPU, shutdown the ports before VSL is unconfigured.
• After adding, deleting, or modifying VSL ports, write the config to nvram (that is, startup-config).
• If you need to move ports to another port, account for the bandwidth requirement of VSL. You should add an additional VSL link in the channel, move ports and remove additional links in the channel.

[jacob.fredriksson]

Since the VSL-link is kind of a port-channel I assumed you couldn't mix 10 Gbit ports with 40 Gbit ports. Normally in port-channels all the physical ports have to have the same speed/bandwidth.

[balaji.bandi]

Yes you are correct, i miss read that, i was in impression all in same speed links, Let me think how can be done with out service interruption or split brain. 

[jacob.fredriksson]

The only solution we have considered is that if you could make a second VSL-portchannel with the 40Gbit-links and have them connected at the same time and they remove the 10Gbit links once everything looks good with show commands. However I cannot find any documentation saying that this is supported (or unsupported for that matter).

[Leo Laohoo]

No way. Upgrading the VSL link from 10- to 40 Gbps means breaking the VSS. This equates to an outage.