SYSTEMS AND METHODS FOR A SELF-HEALING CARRIER ETHERNET TOPOLOGY

• US 20090073988A1
• Filed: 09/14/2007
• Published: 03/19/2009
• Est. Priority Date: 09/14/2007
• Status: Active Grant

• Current Assignee: Ciena Corporation
• Original Assignee: Ciena Corporation
• Inventors: Duncan, Ian, Ghodrat, Morteza, Gazier, Michael
• Granted Patent: US 8,305,884 B2
• Time in Patent Office: Days
• US Class Current: 370/395.530
• CPC Class Codes: H04L 1/22 using redundant apparatus to increase reliability
• CPC Class Codes: H04L 12/4641 Virtual LANs, VLANs, e.g. virtual private networks [VPN] LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272
• CPC Class Codes: H04L 43/0811 by checking connectivity
• CPC Class Codes: H04L 43/10 Active monitoring, e.g. heartbeat, ping or trace-route
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/28 using route fault recovery

Abstract

Systems and methods for self-healing Ethernet topologies which are compatible with PBT, which use standards-based protocols, which do not self-configure, and which use Ethernet OAM are provided. Interconnected nodes are configured with a primary and secondary path which is determined by VLANs, MPLS label, Provider Backbone Bridge Traffic Engineering (PBB-TE) VLAN ID (VID), Frame Relay (FR), Asynchronous Transfer Mode (ATM) Virtual Circuits (VCs), and the like. One or more head-end nodes are designated for terminating each path and for performing cross-connects between the primary and secondary paths. IEEE 802.1ag Continuity Check Messages (CCM) are transmitted by all nodes on both the primary and secondary routes. Responsive to a loss of a predetermined number of CCM messages, traffic is switched to the secondary route. In non-fault conditions, both the paths for the primary and secondary routes can carry traffic.

Claims

1. A method for self-healing Carrier Ethernet, comprising:

statically provisioning a first and second path between a plurality of nodes interconnected in one of a ring and a linear chain topology, wherein one of the plurality of nodes comprises a head-end node configured to provide switching on the first and second paths for local and external network traffic;

provisioning a management channel;

transmitting data from a source node on the first path;

periodically generating distinct Continuity Check Messages (CCMs) on the management channel for each of the first and second paths;

monitoring the distinct CCMs to determine a failure condition within a path;

responsive to the failure condition, transmitting a CCM with a Remote Defect Indicator to the source node; and

switching data from the first path to the second path at the source node responsive to the CCM with the Remote Defect Indicator.

2. The method for self-healing Carrier Ethernet of claim 1, wherein the first and second paths comprise one of a Virtual Local Area Network (VLAN), Multi-protocol Label Switching (MPLS) label, Provider Backbone Bridge Traffic Engineering (PBB-TE) VLAN ID (VID), Frame Relay (FR), and Asynchronous Transfer Mode (ATM) Virtual Circuit (VC).

3. The method for self-healing Carrier Ethernet of claim 1, wherein the CCMs are multicast by each of the plurality of nodes, and the one of the ring and linear chain topology are operable to constrain the multicast CCMs to traversing the one of the ring and linear chain without modification of the multicast CCMs.

4. The method for self-healing Carrier Ethernet of claim 3, wherein the plurality of interconnected nodes comprise the ring topology, and wherein the management channel comprises two IEEE 802.1ag CCM sessions for the ring, wherein the two IEEE 802.1ag CCM session comprise one in a transmit direction and one in a receive direction around the ring.

5. The method for self-healing Carrier Ethernet of claim 4, wherein generating distinct CCMs further comprises:

generating a first and second CCM message at a predetermined rate by a source node of the plurality of nodes;

transmitting the first CCM message in a first direction around the ring;

transmitting the second CCM message in a second direction around the ring, wherein the second direction is opposite from the first direction; and

removing the first and second CCM messages at the source node following a full circle on the ring.

6. The method for self-healing Carrier Ethernet of claim 5, wherein transmitting a CCM with a Remote Defect Indicator to the source node responsive to the failure condition comprises:

when a primary path fails, generating a CCM message with the Remote Defect Indicator (RDI) turned on, wherein the CCM message is generated at a node of the plurality of nodes located on the receive side of the failed primary path; and

receiving the CCM message with the Remote Detect Indicator (RDI) turned on at each of the plurality of nodes indicating a failure.

7. The method for self-healing Carrier Ethernet of claim 1, wherein the monitoring to determine the failure condition comprises one of checking for the loss of a predetermined number of consecutive CCM messages for the first path, receiving a CCM message with a Remote Defect Indicator (RDI), loss of signal, and combinations thereof.

8. The method for self-healing Carrier Ethernet of claim 1, wherein the first and second path are statically provisioned through one of a northbound interface, a command line interface, an Extensible Markup Language (XML) or Session Initiation Protocol (SIP) mechanism, a Provider Backbone Transport (PBT (PBB-TE)) managed system, and combinations thereof.

9. The method for self-healing Carrier Ethernet of claim 1, wherein each of the plurality of nodes connects directly to the head-end through a dedicated VLAN providing a logical tree topology.

10. A self-healing Carrier Ethernet ring, comprising:

a plurality of nodes interconnected in a ring topology;

a head-end node comprising one of the plurality of nodes;

a primary path between each of the plurality of nodes and the head-end;

a protect path between each of the plurality of nodes and the head-end;

means for detecting a failure in the primary and protect path; and

means for switching from the primary path to the protect path responsive to detecting the failure.

11. The self-healing Carrier Ethernet ring of claim 10, further comprising:

primary Virtual Local Area Networks (VLANs) comprising statically provisioned VLANs between each of the plurality of nodes and the head-end node; and

protected VLANs comprising statically provisioned VLANs between each of the plurality of nodes and the head-end node;

wherein the primary path comprises the primary VLANs and the protect path comprises the protect VLANs.

12. The self-healing Carrier Ethernet ring of claim 11, wherein each of the primary and protected VLANs is passthrough intermediate nodes of the plurality of nodes and terminated at an originating node and the head-end node.

13. The self-healing Carrier Ethernet ring of claim 11, wherein the primary and protect VLANs are statically provisioned through one of a northbound interface, a command line interface, an Extensible Markup Language (XML) or Session Initiation Protocol (SIP) mechanism, a Provider Backbone Transport (PBT (PBB-TE)) managed system, and combinations thereof.

14. The self-healing Carrier Ethernet ring of claim 10, wherein responsive to switching from the primary path to the protect path, low priority traffic is dropped if there is oversubscription.

15. The self-healing Carrier Ethernet ring of claim 10, wherein the failure comprises one the loss of a predetermined number of consecutive CCM messages, receipt of a CCM message with a Remote Defect Indicator (RDI), loss of signal, and combinations thereof.

16. A logical tree topology providing a self-healing Ethernet topology, comprising:

a plurality of head-end nodes;

a plurality of nodes, wherein each node is connected to each of the plurality of head-nodes through a dedicated primary and protect path;

a management channel connected to each of the plurality of head-nodes and nodes, wherein multicast Continuity Check Messages (CCMs) are generated and monitored by the plurality of head-end nodes and the plurality of nodes on the management path; and

means for switching from the primary path to the protect path responsive to CCM message with an RDI flag;

wherein the logical tree topology is operable to constrain the path of the multicast CCMs.

17. The logical tree topology providing a self-healing Ethernet topology of claim 16, wherein the primary and protect paths comprise one of a Virtual Local Area Network (VLAN), Multi-protocol Label Switching (MPLS) label, Provider Backbone Bridge Traffic Engineering (PBB-TE) VLAN ID (VID), Frame Relay (FR), and Asynchronous Transfer Mode (ATM) Virtual Circuit (VC).

18. The logical tree topology providing a self-healing Ethernet topology of claim 16, wherein the plurality of head-end nodes and the plurality of nodes monitor CCM messages and responsive to a loss of a predetermined number of CCM messages, transmit a CCM message with an RDI flag.

19. The logical tree topology providing a self-healing Ethernet topology of claim 18, wherein CCMs are generated at a predetermined interval from each node;

wherein each node is configured to remove CCM messages transmitted from itself following traversal of the management channel; and

wherein a node is configured to transmit the CCM message with an RDI flag responsive to the loss of a predetermined number of consecutive CCM messages.

20. The logical tree topology providing a self-healing Ethernet topology of claim 19, wherein the predetermined number of consecutive CCMs and the predetermined interval are selected to provide a failure detection in less than a prescribed time required for recovery.