Cisco Catalyst Blade Switch 3020 in C Class 7000 Enc.

[Nunney]

Hi Gents,

Could some one assist/comment on this please?

The CCBS3020 switches can be installed in pairs/clusters into the rear of the C7000 enclosure communicating with each other across the back plane. If the primary switch fails the service will fall over to the backup switch automatically. However, if a new switch is installed the backup switch recognises this & tries to switch the service back automatically, to the replacement 3020.
Unless the new switch is pre-configured it will load a default config (Already on the replacement switch)which would not match any of the vlan or addressing info associated with the enclosure setup. which could lead to a service outage.

I know this is true of the OA Modules, but does the same thing happen on the switches as well????

[Jack Howes]

I don't think the service automatically switches over the the replacement switch. In a normal situation you may have NIC teaming set up with a NIC from each blade configured on a different switch. If the (Active) Switch fails, the othe NIC becomes active and assuming you have a redundant uplike the spanning tree topology sends traffic up the other link. You now put in the replacement switch and make sure it doesn't have an uplink connected so data will still travel up the redundant link. I don't think the link across the backplane is configured as up. You cna no configure the replacement switch and then turn this link on, and then (again depending on your topology) spanning tree could switch in the other direction and take you back to your original configuration.

[Jack Howes]

Wow that's some bad typing. It should say

You can nwo configure the replacement switch and then turn this link on and then (again depending on your topology) spanning tree could switch in the other direction and take you back to your original configuration.