Catalyst 4500 in VSS - Migrate VSL link from 1Gig to 10Gig

[Bob Goal]

Hi Community,

Customer has got Catalyst 4506 with SUP 7L-E in VSS pair. VSL consists of 4x1Gig in the etherchannel sourced from Supervisor linecard. Is somebody experienced in migrating this kind of setup to 10Gig ports for VSL? Kindly crosscheck my thinking:

My plan(in maintenance windows):

0) Existing VSL consists of 4x1Gig in the etherchannel 

1) Add two additional 10Gig ports to the existing VSL etherchannel. I suspect they will go to the suspended state because of speed mismatch with existing 1Gig ports.

2) Reload whole VSS, two switches. Old 1Gig ports disconnected, 10Gig ports connected

3) VSL should work on 10Gig ports

4) Remove 1Gig ports from the etherchannel

hw-module uplink select gigabitethernet
!
interface Port-channel1
switchport
switch virtual link 1
!
interface Port-channel2
switchport
switchport mode trunk
switchport nonegotiate
switch virtual link 2
!
interface GigabitEthernet1/1/3 - 6
no lldp transmit
no lldp receive
no cdp enable
channel-group 1 mode on
service-policy output VSL-Queuing-Policy
!
interface GigabitEthernet2/1/3 - 6
 switchport mode trunk
 switchport nonegotiate
 no lldp transmit
 no lldp receive
 no cdp enable
 channel-group 2 mode on
 service-policy output VSL-Queuing-Policy

[Bob Goal]

I made this change in steps described in previous post - worked fine.

[antmich1]

Just to add my grain of salt on this topic, since i ran into this situation yesterday :

On C9500, it seems like the speed mismatch prevents the higher throughput links to join the VSL. In order to fix the issue, just remove the stackwise-virtual link configuration on your slow interfaces and add it to the fast ones. The configuration only applies after a reload. Doing it this way avoids the issue of speed mismatch because the switch assumes that at the next reboot, there will be no speed mismatch since the slow interfaces are going to be removed at the same time as the fast ones are added.

Hope this helps !