I currently have 2 ds3 circuits. One circuit was provisioned by RCN and the other is from Verizon. The circuits connect our office to our datacenter and trunk the necessary VLANs on all trunks ports the circuits where the circuits are connected. STP is allowed across which allows us to assign all the VLANs to both circuits and prevents loops.
We had an incident where one of the bidirectional link was broken on one ds3. This was caused but a provider equipment failure along the path but not within our premises. The port remained up and a loop was created which severely affected our network until the unidirectional link was shutdown.
After doing some research I read about UDLD and thought it would work to prevent this from happening. Unfortunately this will not work on my RCN link. The circuit is built on RCN's SONET platform and the edge devices will not pass this protocol. My question is what can I use as on alternative for UDLD on circuits that cannot support this Cisco-proprietary protocol?
I was given the option to move to RCN's Ethernet platform which will allow us to pass this protocol but that might require an additional charge. Thanks for your help in advance.
ps - both circuits are terminated into cat6509 switches on either side of the circuit.