Backbone Provider Bridging Networks

Abstract

An edge device is used to support a backbone provider bridging network to facilitate interconnection of a plurality of networks. The edge device is coupled between the backbone and a first one of the networks, and is operable to encapsulate data units received from the first network with a header, and to forward the encapsulated data unit to the backbone. The header is indicative of a tunnel that is used to support traffic from the first network to a second network over the backbone. The edge device also de-encapsulates data units received from the backbone that are destined for the first network.

What is claimed is: 
     
         1 . A method of interconnecting a first provider bridge network and a second provider bridge network, comprising:
 providing a backbone provider bridge network, the backbone provider bridge network comprising a first backbone provider bridge edge device for connection to the first provider bridge network and a second backbone provider bridge edge device for connection to the second provider bridge network, the first backbone provider bridge edge device being coupled to the second provider bridge edge device over the backbone provider bridge network; and   configuring the first backbone provider bridge device:
 to receive a data unit from the first provider bridge network, the data unit having a header comprising a Service Virtual Local Area Network (S-VLAN) Identifier which is associated with the first and second provider bridge networks; 
 to encapsulate the received data unit with a Backbone VLAN Identifier (B-VID) which is indicative of a backbone VLAN tunnel to be used to transport the S-VLAN over the backbone provider bridge network and an Extended S-VLAN Identifier (ES-VID) which is associated with the S-VLAN Identifier (S-VID); and 
 to forward the encapsulated data unit over the backbone VLAN tunnel toward the second backbone provider bridge edge device. 
   
     
     
         2 . The method of  claim 1 , further comprising forwarding the encapsulated data unit over the backbone VLAN tunnel toward the second backbone provider bridge edge device. 
     
     
         3 . The method of  claim 2 , wherein:
 the backbone provider bridge network comprises a third backbone provider bridge edge device which is associated with the S-VLAN;   the backbone VLAN tunnel is a point to multi-point tunnel linking the first backbone provider bridge edge device to the second and third backbone provider bridge edge devices; and   forwarding the encapsulated data unit over the backbone VLAN tunnel comprises forwarding the encapsulated data unit over the backbone VLAN tunnel toward both the second and third backbone provider bridge edge devices.   
     
     
         4 . The method of  claim 1 , comprising configuring the second backbone provider bridge edge device:
 to receive the encapsulated data unit forwarded from the first backbone provider bridge device;   to decapsulate the encapsulated data unit by removing the B-VID; and   to forward the decapsulated data unit to the second provider bridge network.   
     
     
         5 . The method of  claim 2 , comprising:
 configuring the second backbone provider bridge edge device:
 to receive the encapsulated data unit forwarded from the first backbone provider bridge device; 
 to decapsulate the encapsulated data unit by removing the B-VID; and 
 to forward the decapsulated data unit to the second provider bridge network based on the S-VID; and 
   forwarding the decapsulated data unit to the second provider bridge network.   
     
     
         6 . The method of  claim 1 , comprising configuring the first backbone provider bridge edge device:
 to receive an encapsulated data unit forwarded from the second backbone provider bridge device, the encapsulated data unit having a header comprising the B-VID;   to decapsulate the encapsulated data unit by removing the B-VID; and   to forward the decapsulated data unit to the first provider bridge network.   
     
     
         7 . The method of  claim 2 , comprising:
 configuring the first backbone provider bridge edge device:
 to receive an encapsulated data unit forwarded from the second backbone provider bridge device, the encapsulated data unit having a header comprising the B-VID; 
 to decapsulate the encapsulated data unit by removing the B-VID; and 
 to forward the decapsulated data unit to the first provider bridge network; and 
   forwarding the decapsulated data unit to the first provider bridge network.   
     
     
         8 . The method of  claim 1 , wherein configuring the first backbone provider bridge edge device to
 encapsulate the received data unit with an ES-VID comprises configuring the first backbone bridge device to replace the S-VID with the ES-VID and the B-VID.   
     
     
         9 . The method of  claim 5 , wherein configuring the second backbone provider bridge edge device to decapsulate the encapsulated data unit comprises configuring the second backbone provider bridge edge device to replace the ES-VID and the B-VID with the S-VID. 
     
     
         10 . The method of  claim 6 , wherein configuring the first backbone provider bridge edge device to decapsulate the encapsulated data unit comprises configuring the first backbone provider bridge edge device to replace the ES-VID and the B-VID with the S-VID. 
     
     
         11 . The method of  claim 1 , wherein the backbone provider bridge network comprises:
 a first domain comprising the first backbone provider bridge edge device;   a second domain comprising the second backbone provider bridge edge device; and   a third domain comprising a third backbone provider bridge edge device coupled to the first domain and a fourth backbone provider bridge edge device coupled to the second domain, the fourth backbone provider bridge edge device being coupled over the third domain to the third backbone provider bridge edge device.   
     
     
         12 . The method of  claim 11 , wherein:
 the first domain uses a first B-VID to forward data units over a tunnel in the first domain which is associated with the first and second provider bridge networks;   the second domain uses a second B-VID to forward data units over a tunnel in the second domain which is associated with the first and second provider bridge networks; and   the third domain uses a third B-VID to forward the data units over a tunnel in the third domain which is associated with the first and second provider bridge networks.   
     
     
         13 . The method of  claim 12 , wherein the third backbone provider bridge edge device is configured to insert the third B-VID in data units received from the first domain having the first B-VID for forwarding of the received data units over the third domain. 
     
     
         14 . The method of  claim 13 , wherein the third backbone provider bridge edge device is configured to insert the third B-VID in data units received from the first domain having the first B-VID by swapping the third B-VID for the first B-VID. 
     
     
         15 . The method of  claim 13 , wherein the fourth backbone provider bridge edge device is configured to insert the second B-VID in received data units having the third B-VID for forwarding of the received data units over the second domain to the second backbone provider edge device. 
     
     
         16 . The method of  claim 15 , wherein the fourth backbone provider bridge edge device is configured to insert the second B-VID in received data units having the third B-VID by swapping the second B-VID for the third B-VID. 
     
     
         17 . The method of  claim 1 , wherein the backbone provider bridge network is a multi-layer hierarchical network. 
     
     
         18 . The method of  claim 17 , comprising using B-VID swapping at boundaries between layers in the multilayer hierarchical network to forward data units over respective selected tunnels in the layers of the multilayer hierarchical network. 
     
     
         19 . The method of  claim 18 , wherein B-VIDs are selected for data units received at boundaries between layers in the multi-layer hierarchical network based on ES-VIDs carried by the data units. 
     
     
         20 . The method of  claim 17 , comprising B-VID stacking at boundaries between layers in the multi-layer hierarchical network to forward data units selectively over respective tunnels at each layer of the multilayer hierarchical network.