METHOD AND APPARATUS FOR EXCHANGING ROUTING INFORMATION AND ESTABLISHING CONNECTIVITY ACROSS MULTIPLE NETWORK AREAS
First Claim
1. A method for ensuring that multicast packets follow a same loop-free path as a path followed by unicast packets in a packet communication network, the packet communication network including at least one first area defined by a first level, each first area including a first plurality of nodes interconnected by a first set of links, each first area interconnected through at least one area border node to a second area defined by a second level, the second area including a second plurality of nodes interconnected by a second set of links, each area border node having at least one first level port connected to the at least one first area and a second level port connected to the second area, each multicast packet forwarded over the loop-free path including a header having a root-id identifying a root of a multicast tree, the method comprising:
- receiving at least one data packet at an area border node; and
responsive to receiving a multicast packet at a second level port of an area border node;
examining the root-id of the multicast packet;
determining whether the multicast packet is to be forwarded on at least one of the first level ports of the area border node; and
responsive to determining that the multicast packet is to be forwarded over at least one of the first level ports, substituting a different root-id into the packet before forwarding the packet over the at least one first level port.
7 Assignments
0 Petitions
Accused Products
Abstract
A method ensures that multicast packets follow the same loop-free path followed by unicast packets in a packet communication network. The communication network includes at least one first area interconnected through at least one area border node (“ABN”) to a second area. Each ABN has a first level port connected to each first area and a second level port connected to the second area. Each multicast packet forwarded includes a header having a root-id identifying a root of a multicast tree. A data packet is received at an ABN. Responsive to receiving a multicast packet at a second level port of an area border node, the root-id of the multicast packet is examined and if the multicast packet is to be forwarded over at least one of the first level ports, a different root-id is substituted into the packet before the packet is forwarded over the first level port.
85 Citations
20 Claims
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1. A method for ensuring that multicast packets follow a same loop-free path as a path followed by unicast packets in a packet communication network, the packet communication network including at least one first area defined by a first level, each first area including a first plurality of nodes interconnected by a first set of links, each first area interconnected through at least one area border node to a second area defined by a second level, the second area including a second plurality of nodes interconnected by a second set of links, each area border node having at least one first level port connected to the at least one first area and a second level port connected to the second area, each multicast packet forwarded over the loop-free path including a header having a root-id identifying a root of a multicast tree, the method comprising:
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receiving at least one data packet at an area border node; and responsive to receiving a multicast packet at a second level port of an area border node; examining the root-id of the multicast packet; determining whether the multicast packet is to be forwarded on at least one of the first level ports of the area border node; and responsive to determining that the multicast packet is to be forwarded over at least one of the first level ports, substituting a different root-id into the packet before forwarding the packet over the at least one first level port. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An area border node for use in a packet communication network, the packet communication network including at least one first area defined by a first level, each first area including a first plurality of nodes interconnected by a first set of links, each first area interconnected to through at least one area border node to a second area defined by a second level, the area border node comprising:
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at least one first level port connected to each first area, the at least one first level port operable to receive data packets from and transmit data packets to the corresponding first area; a second level port connected to the second area, the second level port operable to receive data packets from and transmit data packets to the second area; at least one processor electrically connected to the at least one first level port and to the second level port, responsive to receiving a multicast packet at a second level port, the multicast packet including a header having a root-id identifying a root of a multicast tree, the processor is operable to; examine the root-id of the multicast packet; determine whether the multicast packet is to be forwarded on at least one of the first level ports of the area border node; and responsive to determining that the multicast packet is to be forwarded over at least one of the first level ports, substituting a different root-id into the packet before initiating forwarding of the packet over the at least one first level port. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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16. The area border node of claim 13, wherein responsive determining that the multicast packet is to be forwarded over at least one of the first level ports, the processor is further operable to:
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responsive to determining that the root-id identifies another subset in the first area served by the area border node, drop the at least one received data packet; and responsive to determining that the root-id does not identify another subset in the first area served by the area border node; replace the root-id with a root-id for a second level pseudo node; and forward the at least one data packet through the subset associated with the area border node.
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17. The area border node of claim 13, wherein responsive to receiving a unicast packet including a single destination address, the destination address identifying a node in the first area not associated with a subset of the area border node, the processor is further operable to:
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responsive to receiving the at least one data packet on an a first level port, forward the at least one data packet through a different first level port; and responsive to receiving the at least one data packet on the second level port, forward the at least one data packet through the second level port towards another area border node.
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18. A packet communication system comprising:
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at least one first area, each first area configured as an link state protocol controlled Ethernet network area, each first area including a first plurality of nodes interconnected by a first set of links; and a second area configured as an link state protocol controlled Ethernet network area, the second area including a second plurality of nodes interconnected by a second set of links, the second area interconnected to each first area; at least one area border node interconnecting the second area to each first area, the at least one border node operable to serve two or more disjoint first areas, each area border node including; a second level port connected to the second area, the second level port operable to receive data packets from and transmit data packets to the second area; at least one first level port operable connected to each first area, the at least one first level port operable to receive data packets from and transmit data packets to the corresponding first area; at least one processor electrically connected to the second level port and to the at least one first level port, responsive to receiving a multicast packet at a second level port, the multicast packet including a header having a root-id identifying a root of a multicast tree, at least one processor is operable to; examine the root-id of the multicast packet; determine whether the multicast packet is to be forwarded on at least one of the first level ports of the area border node; and responsive to determining that the multicast packet is to be forwarded over at least one of the first level ports, substituting a different root-id into the packet before initiating forwarding of the packet over the at least one first level port. - View Dependent Claims (19, 20)
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Specification