Method and apparatus for traffic engineering in shortest path bridged networks

摘要

A method and apparatus for diverting traffic in a communications network are disclosed. According to one aspect, the invention provides a communications network with a first node and a second node. Connecting these two nodes is a first set of intermediate nodes on a first path (the true shortest path) and a second set of intermediate nodes on a second alternate path. At a first node, a first processor determines whether a packet arriving at the first node must transit the second node. If so, the base virtual local area network (VLAN) identifier (VID) of the packet is replaced by a first VID, and the packet is transmitted along the second path through the second set of intermediate nodes to the second node. At the second node, a second processor determines whether a packet arriving at the second node must transit the first node. If so, the base VID of the packet is replaced by a second VID different from the first VID and different from the base VID, and the packet is transmitted along the second path through the second set of intermediate nodes to the first node.

主权项

1. A method of diverting packets of information in a communications network between a first node and a second node from a first shortest path to a second path, the second path different from the first shortest path, the method comprising:
associating a first virtual local area network (VLAN) identifier (VID) with the second path in a first direction from the first node toward the second node; associating a second VID with the second path in a second direction from the second node toward the first node, the second VID being different from the first VID; diverting packets from the first shortest path to a link being a first hop on the second path when the packets have a Media Access Control (MAC) destination address of a location reachable via the first shortest path between the first node and the second node by reducing a cost of the second path to be less than or equal to a cost of the first shortest path by setting the cost of the second path based on the cost of the first shortest path for a shortest path calculation at the first node; assigning the first VID to all packets transiting a link being a first hop in the first direction on the second path, and assigning the second VID to all packets transiting a link being a first hop in the second direction on the second path, wherein a routing protocol of the first shortest path and a routing protocol of the second path are a same routing protocol; and establishing a first forwarding table at the first node that directs packets having a first MAC address to transit the second path, wherein the first MAC address addresses a location reachable by the first shortest path in the absence of packet diversion.