Virtual path ring protection method and apparatus

A Synchronous Optical Network SONET Unidirectional Path Switched Ring UPSR Virtual Path Ring VPR network, comprising:

• a SONET UPSR carrying Asynchronous Transfer Mode ATM traffic by directing incoming ATM cells to destinations via a Virtual Path VP;
• at least two SONET VPR nodes, each node including:
• at least one line card;
• and
• at least one SONET card protecting said virtual path by an Intra-Ring Communication IRC protocol, wherein said IRC protocol:
• identifies a Bit Error Rate BER of an STS-N communication link;
• collects statistical information on the BER of said communication link;
• compares said statistical information to a pre-determined threshold;
• and
• when a high BER occurs on said communication link, inserts an Path Alarm Signal Indicator AIS-P onto the STS-N if the STS-N exceeding the threshold is carrying TDM traffic;
• and
• notifies at least one other SONET VPR node if the STS-N exceeding the threshold is carrying ATM traffic;
• and
• at least one Synchronous Transport Signal-N STS-N communication link between said SONET VPR nodes.

A Synchronous Optical Network SONET Virtual Path Ring VPR node of a SONET Unidirectional Path Switched Ring UPSR for transmitting and receiving Asynchronous Transfer Mode ATM and Time Division Multiplexer TDM traffic comprising:

• a first SONET card electrically connected to a clockwise CW communications ring for receiving and transmitting ATM and TDM traffic and communicating with at least one other SONET VPR node via an Intra-Ring Communication IRC protocol;
• a second SONET card electrically connected to a counter-clockwise communications ring for receiving and transmitting ATM traffic and communicating with at least one other SONET VPR node via said IRC protocol;
• and
• an electrical connection between the said first and second SONET cards, wherein said SONET UPSR is comprised of Synchronous Transport Signal-Ns STS-Ns, and wherein said SONET VPR node's IRC protocol:
• identifies a Bit Error Rate BER of an STS-N communication link;
• collects statistical information on the BER of said communication link;
• compares said statistical information to a pre-determined threshold;
• and
• when a high BER occurs on said communication link, inserts an Path Alarm Signal Indicator AIS-P onto the Synchronous Transport Signal-N STS-N if the STS-N is exceeding the threshold and the STS-N is carrying TDM traffic;
• and
• notifies at least one other SONET VPR node if the STS-N is exceeding the threshold and the STS-N is carrying ATM traffic.