Method and apparatus for traffic engineering in shortest path bridged networks
First Claim
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.
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Abstract
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.
14 Citations
19 Claims
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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:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A first node in a communications network, the first node configured to route traffic from an input port of the first node to one of a first output port or a second output port of the first node, the first node comprising:
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a memory, the memory storing a forwarding table, the forwarding table directing packets having a first Media Access Control (MAC) address to transit a second path via the second output port, the directed packets being assigned a first virtual local area network (VLAN) identifier (VID), the directed packets received at the first node initially having a base VID, the first VID being different from the base VID; and a processor in communication with the memory, the processor configured to; inspect a first MAC destination address in a header of a first packet received at the first node; determine that the inspected first MAC destination address is an address of a location reachable via the second port; divert the first packet to the second port 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; and replace the base VID of the packet with the first VID, wherein a routing protocol of a first shortest path and a routing protocol of the second path are a same routing protocol, and wherein the base VID is further associated with the first shortest path to a second node that is reachable via the first port in the absence of packet diversion. - View Dependent Claims (10, 11)
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12. A communications network comprising:
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a first node; a second node; and a first set of one or more intermediate nodes on a first path between the first and second nodes, the first path being a shortest path between the first and second nodes, and a second set of one or more intermediate nodes on a second path between the first and second nodes; the first node having a first processor, the first processor configured to; inspect a first Media Access Control (MAC) address in a header of a first packet; determine that the first packet must transit the second node to reach a destination based on the inspected first MAC address; divert the first packet to the second node by replacing a base virtual local area network (VLAN) identifier (VID) with a first VID in the header of the first packet and reduce 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; and transmit the first packet to the second node along the second path through the second set of one or more intermediate nodes, wherein a routing protocol of the first path and a routing protocol of the second path are a same routing protocol, and wherein the base VID is further associated with the first shortest path to a second node that is reachable via the first port in the absence of packet diversion. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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Specification