Utilizing optical bypass links in a communication network

Abstract

Optical By-Pass (OBP) links may be created by adding wavelengths between nodes on the network. The OBP may extend between any pair of nodes on the network. Intermediate nodes on the OBP are transient nodes and simply forward traffic optically. An OBP extends between a pair of nodes and, unlike express links, is created in such a manner that it does not affect the previous allocation of resources on the network. This enables capacity to be added between pairs of nodes on the network to alleviate congestion at a portion of the network, without changing other traffic patterns on the network. This enables inclusion of an OBP to be deterministic and of linear impact on the network. The OBP links may be statically provisioned or created on demand. Optionally, the OBP links may be crated to coincide with PBB-TE tunnels on the network.

What is claimed is: 
     
         1 . A method of routing traffic in a communication network comprising a plurality of network nodes interconnected by a plurality of links, the communication network being configured to route data over links of the network according to a routing protocol, the communication network comprising a hop-by-hop path between a first node and a second node via a plurality of links and at least one intermediate node, the method comprising:
 configuring a bypass link between the first node and the second node, the bypass link being configured to carry traffic between the first node and second node without routing the traffic at the at least one intermediate node; and   diverting selected traffic to the bypass link from the hop-by-hop path between the first node and the second node in at least one of the first and second nodes responsive to configuration of the bypass link, without modifying routing of traffic at network nodes other than the first and second nodes responsive to configuration of the bypass link.   
     
     
         2 . The method of  claim 1 , wherein network nodes other than the first and second nodes are not aware of the bypass link between the first and second nodes. 
     
     
         3 . The method of  claim 1 , wherein network nodes other than the first and second nodes are not informed of configuration of the bypass link. 
     
     
         4 . The method of  claim 1 , wherein network nodes other than the first and second nodes are informed of configuration of the bypass link, but do not modify their routing of traffic in response to configuration of the bypass link. 
     
     
         5 . The method of  claim 4 , wherein routing functions at network nodes other than the first and second nodes associate a cost with the bypass link that is high enough to prevent network nodes other than the first and second nodes from adjusting forwarding tables responsive to configuration of the bypass link. 
     
     
         6 . The method of  claim 1 , wherein the bypass link follows a path through at least one intermediate node, but traffic is neither added nor dropped at the at least one intermediate node. 
     
     
         7 . The method of  claim 1 , wherein the bypass link is configured to switch traffic at the at least one intermediate node without processing data units of the traffic. 
     
     
         8 . The method of  claim 1 , wherein the bypass link is an optical bypass link. 
     
     
         9 . The method of  claim 8 , wherein the optical bypass link is configured to optically switch traffic at the at least one intermediate node without processing data units of the traffic. 
     
     
         10 . The method of  claim 1 , wherein at least one of the first and second nodes is configured to aggregate traffic onto the bypass link to alleviate congestion on the hop-by-hop path between the first node and the second node. 
     
     
         11 . The method of  claim 1 , wherein the first and second nodes are configured to divert traffic onto the bypass link by providing switching functions at the first and second nodes, the switching functions being provided outside of routing/forwarding functions of the first and second nodes and being configured to selectively divert traffic onto the bypass link. 
     
     
         12 . The method of  claim 11 , wherein the switching functions comprise sorting functions configured to selectively divert similarly addressed traffic over the bypass link. 
     
     
         13 . The method of  claim 12 , wherein the sorting functions apply policies local to the first and second nodes. 
     
     
         14 . The method of  claim 13 , wherein the policies are applied on a per-flow basis. 
     
     
         15 . The method of  claim 11 , wherein the switching functions comprise a hop-by-hop path queue for data units to be transmitted over the hop-by-hop path and a bypass link queue for data units to be transmitted over the bypass link, and the switching functions are responsive to monitored occupancies of the hop-by-hop path queue and the bypass link queue to selectively divert traffic to the bypass link. 
     
     
         16 . The method of  claim 1 , wherein the bypass link is statically provisioned. 
     
     
         17 . The method of  claim 1 , wherein the bypass link is dynamically configured based on traffic on the hop-by-hop path between the first node and the second node. 
     
     
         18 . The method of  claim 1 , wherein the network implements IEEE 802.1Qay and the bypass link corresponds to a Provider Backbone Bridge Traffic Engineering (PBB-TE) tunnel. 
     
     
         19 . The method of  claim 18 , wherein the bypass link is configured in response to advertisement of a PBB-TE tunnel when bandwidth advertised for the PBB-TE tunnel exceeds a predetermined bandwidth. 
     
     
         20 . The method of  claim 18 , wherein the bypass link is configured when traffic monitored on the PBB-TE tunnel exceeds a predetermined amount. 
     
     
         21 . The method of  claim 1 , comprising adjusting a loop prevention mechanism at the second node to enable diverted traffic received over the bypass link to be accepted by the second node. 
     
     
         22 . The method of  claim 1 , comprising responding to failure of the bypass link by pushing traffic onto the hop-by-hop path between the first node and the second node. 
     
     
         23 . The method of  claim 1 , comprising responding to failure of the bypass link by configuring a second bypass link, the second bypass link being diversely routed relative to the failed bypass link.