Cisco 9500 - move VSL connections

[Craig01]

Hi,

I have 2 9500's that are currently stacked using VSL over 2 x 10G fibre connections. I am moving these to 2 x 40G Twinax connections shortly, and just wanted to understand the impact. 

1. As I am moving to a faster connection, I assume I must disable the 10G first, then enable the 40G.

2. If I shut down 1 switch, move the connections and then bring it back up, will it rejoin the stack, or would I need to restart both switches to re-negotiate the stack?

If anyone has any advice on this activity it would be appreciated.

Thanks

[Reza Sharifi]

Hi Craig,

If all the access switches are connected to both 9500 chassis, there is very little traffic that traverses the VSL link, therefore 2 10Gig interfaces are more than enough to handle the amount of traffic between 2 chassis. That said, if you need to move from 10 to 40Gig, you would need to configure the new 40Gig Pochannel, disconnect the 10Gigs, connect the 40Gigs, and then reboot one chassis at a time for the configuration to take effect. From the config guide document:

• Dual-Active Detection (DAD) and SVL configuration must be performed manually and the devices should be rebooted for the configuration changes to take effect.

• https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9500/software/release/17-9/configuration_guide/ha/b_179_ha_9500_cg/configuring_cisco_stackwise_virtual.html
• HTH