PROVIDER LINK STATE BRIDGING
First Claim
1. A provider link state bridging Ethernet node, the node comprising:
- at least one associated unicast media-access-control (MAC) address;
at least one associated multicast MAC address;
a routing module for exchanging link state routing information between nodes based upon the respective unicast MAC address and a plurality of multicast MAC addresses of peer nodes and for determining shortest path connectivity between peer nodes and wherein when multiple equal cost paths are available, the selected shortest path is arranged to be consistent for all bridges participating in the routing information exchange;
a forwarding information base (FIB) populated with forwarding information received from the routing module for identifying connectivity from the node to peer bridge nodes, wherein the unicast MAC addresses point to peer nodes and the multicast address point from peer nodes;
a reverse path forwarding check (RPFC) module for inspecting incoming packets and determining whether the packets arrived on the same ingress port as would be used as an egress port, as determined by the FIB, to forward a packet with a destination MAC address equal to the ingress source MAC address; and
a forwarding module for determining, from the FIB, if an egress port of the node is associated with the destination MAC address of a peer bridge and forwarding the packet.
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Accused Products
Abstract
Provider Link State Bridging (PLSB) expands static configuration of Ethernet MAC forwarding tables by the control plane and utilizes direct manipulation of Ethernet forwarding by a link state routing system. At least one media-access-control (MAC) address for unicast forwarding to the bridge and at least one MAC address for multicast forwarding from the bridge are assigned. Bridges exchange state information by a link state bridging protocol so that a synchronized configured view of the network is shared between nodes. Each node can calculate shortest path connective between peer bridging nodes and populated the appropriate forwarding tables. A reverse path forwarding check is performed on incoming packets to provide loop suppression. During times of network instability the loop suppression can be disabled for unicast packets as identified by the destination MAC address to buffer packets and minimize the impact on traffic flow.
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Citations
33 Claims
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1. A provider link state bridging Ethernet node, the node comprising:
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at least one associated unicast media-access-control (MAC) address;
at least one associated multicast MAC address;
a routing module for exchanging link state routing information between nodes based upon the respective unicast MAC address and a plurality of multicast MAC addresses of peer nodes and for determining shortest path connectivity between peer nodes and wherein when multiple equal cost paths are available, the selected shortest path is arranged to be consistent for all bridges participating in the routing information exchange;
a forwarding information base (FIB) populated with forwarding information received from the routing module for identifying connectivity from the node to peer bridge nodes, wherein the unicast MAC addresses point to peer nodes and the multicast address point from peer nodes;
a reverse path forwarding check (RPFC) module for inspecting incoming packets and determining whether the packets arrived on the same ingress port as would be used as an egress port, as determined by the FIB, to forward a packet with a destination MAC address equal to the ingress source MAC address; and
a forwarding module for determining, from the FIB, if an egress port of the node is associated with the destination MAC address of a peer bridge and forwarding the packet. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of configuring and operating a provider link state bridging Ethernet node in a mesh networks the method comprising:
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exchanging link state information with peer nodes wherein each node has at least one associated unicast media-access-control (MAC) address and at least one multicast MAC address;
determining shortest paths to peer nodes by a shortest path algorithm based upon the exchanged link state information and wherein when multiple equal cost paths are available, the selected shortest path is arranged to be consistent for all bridges participating in the routing information exchange;
populating a forwarding information base (FIB) with the determined shortest paths utilizing associated unicast MAC addresses pointing to peer nodes and multicast MAC addresses pointing from peer nodes;
performing a reverse path forwarding check (RPFC), by determining by inspecting the source MAC address of an incoming packet whether the packet arrived on the same ingress port of the node as would be used as an egress port of the node to forward a packet with a destination MAC address equal to the ingress source MAC address, wherein the packet is discarded if the RPFC fails; and
forwarding the packet to a peer bridge, if the RPFC is successful, via an egress port of the node associated with the destination MAC of the packet as identified in the FIB. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. An Ethernet bridging network comprising:
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a plurality of bridges each having a forwarding information base (FIB) containing forwarding information for peer bridges in the network, each bridge capable of performing a reverse path forwarding check (RPFC) to determine if an incoming packet arrived on the same ingress port of the bridge as would be used as an egress port of the bridge to forward a packet with a destination MAC address equal to the incoming packet'"'"'s source MAC address, a plurality of paths interconnecting the bridges and forming the mesh network; and
wherein the FIB is populated based upon link state information exchanged between the plurality of bridges and is used to determine the shortest path between peer bridges, wherein the determination of the chosen paths when multiple equal cost paths are available is arranged to be consistent for peer bridges. - View Dependent Claims (28, 29, 30, 31, 32, 33)
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Specification