Dual Card Set Redundancy

The fiber linking function supports Dual card set redundancy. Both Card set A and Card set B are fitted in each node of the ring. In this case each matrix contains two Fiber-optic Linking card sets.

This approach affords full redundancy, offering protection against component failure within a single Fiber-optic Linking Card Set.

Parallel operation

The cabling and operation of both cards sets is the same as described in the Single card set redundancy section.

All card set A units in the linked set are network together forming a redundant fiber ring. However additionally all card set B units are additionally networked together to form a parallel redundant fiber ring. There is no fiber linkage between these two parallel fiber networks.

During normal operation each matrix monitors the number of nodes that are reachable on each of the two fiber networks. When there is parity between card set A and card set B then card set A will be used to route audio to and from the matrix.

Loss of fiber connections and nodes

As long all nodes are still deemed to be reachable on Card set A no switchover will be performed to Card set B.

Therefore, even if fiber connection issues on Card set A that a) result in a switch to the secondary ring (on Card set A) or b) result is a switch to loopback mode then Card set A will continue to be used to route audio to and from the matrix.

If sufficient fiber errors occur (either cabling or card failures) that result in the number of reachable nodes on Card set A dropping below that of Card set B, then the matrix will switch to Card set B.

The currently active fiber card can be identified as it will flash its green status LED. The current backup (in active) fiber card will not illuminate its green status LED.