Well I have two 7606 routers and around 40 channelised E1s, I have two STM - 1 mux and four STM - 4 mux at my premises, I need to design a topology such that the two 7606 routers should be redundant i.e. in case of failure another 7606 router should switch over and provide connectivity from my LAN to the MUX.
While searching I found Automatic Protection Switching as one solution where I would have to use sonet card on 7606 routers and this sonet card would connect to an Add/Drop multiplexer.
I need to know whether STM-4 mux can be connected to STM-1 card.
Also, If I use STM - 4 card then can I have 1000 interfaces for channelised E1s on one single STM-4 card?
PA-MC-STM-1 card seems to support only 256 interfaces.
Suppose if I use multiple STM-1 cards and configure APS for redundancy, and only one SONET card fails, so will the switchover be for all the cards or just the for the card which has failed?