Virtual path ring protection method and apparatus

• US 6,553,034 B2
• Filed: 07/14/2001
• Issued: 04/22/2003
• Est. Priority Date: 03/15/1999
• Status: Expired due to Term

• Current Assignee: Tellabs Operations Incorporated (Infinera Corp.)
• Original Assignee: Tellabs Operations Incorporated (Infinera Corp.)
• Inventors: Chan, Eric L., Kornhaus, Leland M., Helfrich, Andy D.
• Primary Examiner(s): Ton, Dang
• Assistant Examiner(s): HOM, SHICK C
• Application Number:
  US09/905,734
• Publication Number:
  US 20010046206A1
• Time in Patent Office: 647 Days
• Field of Search: 370/216, 370/221, 370/222, 370/223, 370/224, 370/395.1, 370/396, 370/397, 370/398, 370/399, 370/403, 370/404, 370/405, 370/409, 370/452, 370/460, 370/217, 370/225, 370/249, 370/258, 370/351, 370/406, 359/115, 359/118, 359/119, 359/135
• US Class Current: 370/397
• CPC Class Codes: H04J 2203/0042 Ring
• CPC Class Codes: H04J 2203/006 Fault tolerance and recovery
• CPC Class Codes: H04J 2203/0071 Monitoring
• CPC Class Codes: H04J 2203/0073 Services, e.g. multimedia, GOS, QOS
• CPC Class Codes: H04J 2203/0096 Serial Concatenation
• CPC Class Codes: H04J 3/085 for ring networks, e.g. SDH/SONET rings, self-healing rings, meashed SDH/SONET networks
• CPC Class Codes: H04L 2012/5605 Fibre
• CPC Class Codes: H04L 2012/5612 Ring
• CPC Class Codes: H04L 2012/5627 Fault tolerance and recovery
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

A method and apparatus for the robust implementation and protection of Asynchronous Transfer Mode (ATM) traffic over a Synchronous Optical Network (SONET) Unidirectional Path Switched Ring (UPSR). The traditional SONET bridging function is eliminated for the ATM traffic in favor of a selector function. The selector function occurs at the ingress of the ATM traffic to the UPSR and directs the ATM traffic to its destination via a virtual path over the UPSR. The ATM traffic is protected from both SONET failures and ATM failures by means of an Intra-Ring Communication (IRC) protocol. The IRC protocol governs failure detection and the notification of the SONET nodes on the UPSR of the failure and any protection switch that may be necessary.

Claims

1. A Virtual Path Ring VPR protection method for Asynchronous Transfer Mode ATM traffic carried over a Synchronous Optical Network SONET Unidirectional Path Switched Ring UPSR, each ATM cell traveling along a Virtual Path VP connection from ingress to egress on the UPSR ring, said SONET UPSR including at least two SONET VPR nodes, each SONET VPR node including at least one SONET card, wherein said SONET UPSR includes at least one Synchronous Transport Signal-N STS-N, comprising:

directing one of said ATM cells incoming to said SONET UPSR to a destination via said VP connection; and

protecting said VP connection by an Intra-Ring Communication protocol, said protecting step comprising;

identifying a Bit Error Rate BER of an STS-N communication link;

collecting statistical information on the BER of said communication link;

comparing said statistical information to a pre-determined BER threshold; and

when a high BER occurs on said communication link, inserting an Path Alarm Signal Indicator AIS-P onto the STS-N if the STS-N is exceeding the BER threshold and the STS-N is carrying TDM traffic; and

notifying another SONET VPR node if the STS-N is exceeding the BER threshold and the STS-N is carrying ATM traffic.

2. 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.

3. 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.