Traffic engineering in frame-based carrier networks

Abstract

The invention relates to enabling traffic engineering in frame-based networks such as Ethernet networks. There is described a method of and connection controller for establishing connections ( 76, 77 ) in a frame-based communications network comprising nodes ( 71 - 75 and 78 ) such as Ethernet switches. The connections are established by configuring, in various of the nodes, mappings for forwarding data frames, such as Ethernet frames. The mappings are from a combination of a) a destination address corresponding to a destination node ( 73 ) of the connection and b) an identifier, such as a VLAN tag. The mappings are to selected output ports of the various nodes. By using the combination of destination address AND identifier, the mappings enable data frames belonging to different connections ( 76, 77 ) to be forwarded differentially (ie forwarded on different output ports) at a node ( 75 ) despite the different connections having the same destination node. This enables flexibility in routing connections—ie the ability to perform traffic engineering.

1 . A method of establishing connections in a frame-based network, the method comprising the step of: 
 configuring, in one or more nodes of the network, first mappings for use in forwarding data frames, the first mappings being from a combination of:    a) a first destination address corresponding to a first destination node of the network, and    b) a first identifier,    the first mappings being to a selected output port of, or to respective selected output ports of each of, the one or more nodes, thereby establishing at least part of a first connection through the one or more nodes to the first destination node.    
   
   
       2 . A method according to  claim 1  comprising the further step of: 
 configuring, in at least one of the nodes, a second mapping for use in forwarding data frames, the second mapping being from a combination of:    a) a second destination address corresponding to a second destination node of the network, and    b) a second identifier,    the second mapping being to a selected output port of the at least one node, thereby establishing at least part of a second connection through the at least one node to the second destination node,    the selected output ports of the at least one node being different for the first and second mappings, thereby enabling, at the at least one node,    differential forwarding of data frames associated with the first and second connections.    
   
   
       3 . A method according to  claim 2 , wherein the first and second destination addresses and the first and second destination nodes are the same.  
   
   
       4 . A method according to  claim 2 , wherein the first and second identifiers are the same.  
   
   
       5 . A method according to  claim 2 , wherein the at least one node associates data frames with one of the first and second connections in dependence on a destination address and identifier of the frame.  
   
   
       6 . A method according to  claim 1 , wherein the network is an Ethernet network and the one or more nodes are Ethernet switches.  
   
   
       7 . A method according to  claim 6 , wherein the identifier is a VLAN tag.  
   
   
       8 . A method according to  claim 1 , wherein the configuration is performed by a control plane of the network.  
   
   
       9 . A method according to  claim 8 , wherein the control plane is ASON/ASTN.  
   
   
       10 . A method according to  claim 1 , wherein the network is at least partially meshed.  
   
   
       11 . A frame-based communications network comprising one or more nodes arranged to perform the method of  claim 1 .  
   
   
       12 . Software arranged to perform the method of  claim 1 .  
   
   
       13 . A connection controller for establishing connections in a frame-based network, the connection controller comprising: 
 a signal generator capable of generating a first signal for configuring, in a transport node of the network, a first mapping for use in forwarding data frames, the first mapping being from a combination of:    a) a first destination address corresponding to a first destination node of the network, and    b) a first identifier,    the first mapping being to a selected output port of the transport node, the first signal thereby establishing at least part of a first connection through the transport node to the first destination node.    
   
   
       14 . A connection controller according to  claim 13 , wherein the signal generator is capable of generating a second signal for configuring, in the transport node of the network, a second mapping for use in forwarding data frames, the second mapping being from a combination of: 
 a) a second destination address corresponding to a second destination node of the network, and    b) a second identifier,    the second mapping being to a selected output port of the transport node, the second signal thereby establishing at least part of a second connection through the transport node to the second destination node,    the selected output ports of the transport node being different for the first and second mappings, the first and second signals thereby enabling, at the transport node, differential forwarding of data frames associated with the first and second connections.    
   
   
       15 . A connection controller according to  claim 14 , wherein the first and second destination addresses and the first and second destination nodes are the same.  
   
   
       16 . A connection controller according to  claim 14 , wherein the first and second identifiers are the same.  
   
   
       17 . A connection controller according to  claim 13 , wherein the network is an Ethernet network and the transport node is an Ethernet switch.  
   
   
       18 . A connection controller according to  claim 17 , wherein the identifier is a VLAN tag.  
   
   
       19 . A connection controller according to  claim 13 , wherein the network is at least partially meshed.  
   
   
       20 . A connection controller according to  claim 13  physically co-located with the transport node.  
   
   
       21 . A frame-based network comprising the connection controller of  claim 13 .  
   
   
       22 . A method of establishing a connection in a frame-based network, the method comprising the steps of: 
 configuring forwarding information in a plurality of nodes of the network the forwarding information enabling the nodes to forward data frames in dependence on a combination of a destination address and an identifier of the data frames.    
   
   
       23 . A method of data traffic engineering in a frame-based network, the method comprising the following steps: 
 establishing a first and second connections in the network passing through a common switching node of the network,    configuring the switching node to forward data frames differently in dependence on differences in either a destination address or an identifier of the data frames, thereby enabling data traffic engineering.    
   
   
       24 . A method of establishing connections in a frame-based network, the method comprising the step of: 
 configuring, in each of a first plurality of nodes of the network, a first forwarding mapping from a first combination of a destination address and an identifier to a selected output port of a respective node of the first plurality of nodes.    
   
   
       25 . A method according to  claim 24  comprising the further step of: 
 configuring, in at least one of the first plurality of nodes, a second forwarding mapping from a second combination of a destination address and an identifier to a selected output port of the at least one node,    wherein the first and second mappings at the at least one node respectively map to different output ports of the at least one node.    
   
   
       26 . A connection controller for establishing connections in a frame-based network, the connection controller being arranged to configure a first forwarding mapping in a transport node, the first mapping being from a first combination of a destination address and an identifier to a first output port of the transport node.  
   
   
       27 . A connection controller according to  claim 26 , the connection controller being arranged to configure a second forwarding mapping in the transport node, the second mapping being from a second, different combination of a destination address and an identifier to a second, different output port of the transport node, thereby to enable differential forwarding of data frames by the transport node in dependence on a combination of a destination address and an identifier of the data frames.  
   
   
       28 . A method of forwarding data frames in a frame-based network, the method comprising the steps of: 
 establishing a first connection in the network, the first connection being associated with a first combination of a destination address and an identifier, and    forwarding data frames in the network in dependence on a combination of a destination address and an identifier of the data frames.    
   
   
       29 . A method according to  claim 28 , wherein the first connection is routed through a switching node having different first and second output ports connected to other nodes of the network, the method comprising the further steps of: 
 establishing a second connection in the network through the switching node, the second connection being associated with a second combination of a destination address and an identifier, different to the first combination, and    the switching node forwarding data frames having the first combination of a destination address and an identifier on the first output port and forwarding data frames having the second combination of a destination address and an identifier on the second output port.