flex links instead of stp for connecting other vendor switches ?

carl_townshend · ‎02-24-2009

After looking into connecting cisco devices to nortel, the stp may not work, after reading up, would an alternative be to use flex links? can I load balance vlans with this? and also how does it work, does the port have to have a line protocol state of down before it reverts to the backup port ?

Mohamed Sobair · ‎02-24-2009

Hi,

Why do you think STP wont work? The only reason is that MST (IEEE standard STP) has some incomapatiblity with the PVST+, but if the Switches running RSTP then it would absolutely work fine.

Cisco has developed the way MST interact with PVST+, you can either:

1) run pre-standard MST on Nortel with PVST+ Cisco bridges and have the loadbalancing in place.

2) run standard PVST+ but this disables the loadbalancing scheme.

If you choose (Flex-Link), then its pretty straight foreward, all you have to do is to designate a port as uplink primary while deignat another uplink to be as backup. You will need to activate also preemtion On the main port. with Flex-link you cant loadbalance unfortunately cause one of the port has to be in Standby mode. Unlike STP..

HTH

Mohamed

carl_townshend · ‎02-24-2009

because on the nortel, they only have one instance of stp running for all the vlans.

what is my solution to this, what would I need to do ?

cheers

Carl