System and Method for Congestion Notification in an Ethernet Oam Network

1. A network element operable in an Ethernet OAM network, comprising: at least one port of the network element operable for configuration as a maintenance end point (MEP) in a first OAM domain; at least one queue assigned to an Ethernet Virtual Connection (EVC), wherein the EVC is monitored by the MEP; at least one processing module configured to: monitoring the at least one queue associated with the MEP; when a congestion level in the at least one queue compares unfavorably to a congestion threshold, performing a statistical sampling on the at least one queue over a first predetermined time period; when the congestion threshold compares unfavorably for the first predetermined time period, triggering a congestion state for the MEP in the first OAM domain; generate a first congestion notification for transmission to one or more other MEPs in the first OAM domain, wherein the first congestion notification includes a congestion measurement field relating to the at least one queue, an identifier for the MEP and an S-VLAN identifier of the EVC assigned to the at least one queue; generate a network management system (NMS) message for transmission to a NMS for the first OAM domain, wherein the NMS message includes congestion information and the identifier for the MEP; and generate a second congestion notification for propagation to another MEP in a second OAM domain at a higher hierarchical level, wherein the second congestion notification includes the congestion information and an identifier for the first OAM domain.

2. The network element of claim 1 , wherein the congestion information includes a percentage of a max queue size consumed at a time of notification and a timestamp field that indicates when congestion was identified on the at least one queue.

3. The network element of claim 1 , wherein the at least one processing module is further configured to: after triggering the congestion state for the MEP in the first OAM domain, monitor the congestion level in the at least one queue associated with the MEP; and when the congestion level in the at least one queue compares favorably to the congestion threshold for a second predetermined period of time, remove the congestion state for the MEP in the first OAM domain.

4. The network element of claim 3 , wherein the at least one processing module is further configured to: generate a third congestion notification for transmission to other MEPs in the first OAM domain, wherein the third congestion notification indicates that the congestion state has been removed for the MEP in the first OAM domain.

5. The network element of claim 4 , wherein the at least one processing module is further configured to: generate another NMS message for transmission to the NMS for the first OAM domain, wherein the another NMS message indicates that the congestion state has been removed for the MEP in the first OAM domain.

6. A network element operable in an Ethernet OAM network, comprising: at least one port of the network element operable for configuration as a first maintenance end point (MEP) in a provider OAM domain at an intermediate hierarchical level; at least one processing module configured to: process a first congestion notification received by the first MEP from a second MEP in an operator OAM domain at a lower hierarchical level, wherein the first congestion notification includes congestion information for the operator OAM domain at the lower hierarchical level; generate a second congestion notification for transmission to another MEP in the provider OAM domain, wherein the second congestion notification includes the congestion information for the operator OAM domain at the lower hierarchical level; generate a network management system (NMS) message for transmission to a NMS for the provider OAM domain at the intermediate hierarchical level, wherein the NMS message includes the congestion information for the operator OAM domain at the lower hierarchical level; generate a third congestion notification for propagation to a third MEP in a customer OAM domain at a higher hierarchical level, wherein the third congestion notification includes the congestion information for the operator OAM domain at the lower hierarchical level; process a fourth congestion notification received by the first MEP from the second MEP in the operator OAM domain at the lower hierarchical level, wherein the fourth congestion notification includes an indication that a congestion state has been removed in the operator OAM domain at the lower hierarchical level; generate a fifth congestion notification for transmission to the another MEP in the provider OAM domain, wherein the fifth congestion notification includes the indication that the congestion state has been removed in the operator OAM domain at the lower hierarchical level; and generate a sixth congestion notification for propagation to the third MEP in a customer OAM domain at a higher hierarchical level, wherein the sixth congestion notification includes the indication that the congestion state has been removed in the operator OAM domain at the lower hierarchical level.

7. The network element of claim 6 , wherein the least one processing module is further configured to: generate another network management system (NMS) message for transmission to the NMS for the provider OAM domain at the intermediate hierarchical level, wherein the NMS message includes the indication that the congestion state has been removed in the operator OAM domain at the lower hierarchical level.

8. A method operable in a network element, comprising: configuring at least one port of the network element as a maintenance end point (MEP) in a first OAM domain; associating at least one queue in the network element to an Ethernet Virtual Connection (EVC), wherein the EVC is monitored by the MEP; determining congestion in the at least one queue associated with the MEP by: monitoring the at least one queue associated with the MEP in the first OAM domain; when a congestion level in the at least one queue compares unfavorably to a congestion threshold, perform a statistical sampling on the at least one queue over a first predetermined time period; when the congestion threshold compares unfavorably for the first predetermined time period, triggering a congestion state for the MEP in the first OAM domain; generating a first congestion notification for transmission to a plurality of other MEPs in the first OAM domain, wherein the first congestion notification includes a congestion measurement field relating to the at least one queue, an S-VLAN identifier of the EVC assigned to the at least one queue and an identifier for the MEP; generating a network management system (NMS) message for transmission to a NMS for the first OAM domain, wherein the NMS message includes congestion information and the identifier for the MEP; generating a second congestion notification for propagation to another MEP in a second OAM domain at a higher hierarchical level, wherein the second congestion notification includes congestion information and an identifier for the first OAM domain; and generating a network management system (NMS) message for transmission to a NMS for the second OAM domain at the higher hierarchical level, wherein the NMS message includes the congestion information for the first OAM domain.

9. The method of claim 8 , wherein the congestion information includes a percentage of a max queue size consumed at a time of notification and a timestamp field that indicates when congestion was identified on the at least one queue.

10. The method of claim 8 , further comprising: after triggering the congestion state for the MEP in the first OAM domain, monitoring the congestion level in the at least one queue associated with the MEP; and when the congestion level in the at least one queue compares favorably to the congestion threshold for a second predetermined period of time, removing the congestion state for the MEP in the first OAM domain.

11. The method of claim 10 , further comprising: generating a third congestion notification for transmission to other MEPs in the first OAM domain, wherein the third congestion notification indicates that the congestion state has been removed for the MEP in the first OAM domain; and generating another NMS message for transmission to the NMS for the first OAM domain, wherein the another NMS message indicates that the congestion state has been removed for the MEP in the first OAM domain.