The present invention is a core interface mechanism that permits 1:N type port
protection on the core side of the switch such that core bandwidth is not wasted
by the direct connection of service cards to the switching core. In an exemplary
embodiment, a core interface module supports up to two active service cards and
one dedicated protection service card. To provide increased efficiency and lower
cost the redundant service card does not strand user bandwidth in the switch core.
In an exemplary embodiment, the core interface includes a plurality of core side
input and output ports for coupling to the switching core and a plurality of card
side input and output ports for coupling to the service cards. A data flow switch
function couples between the core side ports and the card side ports. The data
flow switch function operates to complete data flow paths between the core side
ports and the card side ports. A link failure detector detects a communications
failure on a communications link associated with one of the active service cards
and alters the data flow switch function such that one or more of said data flow
paths associated with one of the active service cards are switched to one of said
protection cards. The bandwidth allotment between the service cards and the interface
device is generally greater than available bandwidth between the switching core
and the interface device, thereby enabling connection of the protection cards without
corresponding usage of switching core bandwidth.
