RSTP compatibility between Cisco and Alcatel Switch

slizarraga · ‎11-07-2016

I have a 3750X stack in my datacenter that is connected with two interface to an Alcatel Core Switch. I have one interface in shutdown state and the other up, so all traffic goes through this last interface.

My Cisco stack runs MSTP and the Alcatel switch runs RSTP. Last weekend I changed the mode in the Cisco stack to RSTP but I lost communication with the Alcatel switch. The port that connected to the Alcatel switch showed in blocked mode.

Is there any compatibility issue or special command I need to configure in order to get this 2 devices to talk and work correctly?

Thanks for your help!!

This is the port configuration:

interface TenGigabitEthernet1/1/1
switchport trunk allowed vlan 101,116-119,125,231,950
switchport trunk encapsulation dot1q
switchport trunk native vlan 231
switchport mode trunk
load-interval 30
no cdp enable
end

Georg Pauwen · ‎11-07-2016

Hello,

Cisco and Alcatel both running MSTP should actually work. When you run MSTP on the Alcatel, do you have 'bridge mode flat' configured ? Can you post the Alcatel config as well ?