Patent ID: 7688833

Claim:
A communications network node for use in a synchronous transmission network and arranged to operate with data frames of at least two different protocol types, said two different protocol types being synchronous digital hierarchy (SDH) and synchronous optical network (SONET), said network node comprising: (a) a single-protocol switch core configured to switch data frames of one of said protocol types; and (b) a conversion processor configured to converting data frames between said two protocol types; said conversion processor being arranged to operate on an ingress of the network node and on an egress of the network node such that data packets frames received at the ingress of the network node which are one-way data frames for passing from one ingress of the network node to one egress of the network node with one pass through the single protocol switch core, which data frames are of a protocol type different from that of the single-protocol switch core, are converted into a form compatible with that of the single-protocol switch core and subsequently, after being processed by the single-protocol switch core, converted back into the protocol type of the received data frames at the egress of the network node.