System, device, and method for reducing multicast forwarding states in a multicast communication system
AssigneeNortel Networks Limited
InventorsYunzhou Li, Shuching Shieh
Life of this patent
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Abstract
A system, device, and method for reducing multicast forwarding states in a multicast communication system maintains forwarding states in such a way that the non-default forwarding states have non-overlapping source address ranges. Each forwarding state is associated with a source address range encompassing one or more source addresses. When a non-default forwarding state is installed, the source address range for the forwarding state is selected so that the source address range does not overlap with the source address ranges of any other non-default forwarding states. The source address range for a particular forwarding state may be adjusted as new routes are learned or existing routes are changed or aged.
Claims97
In a multicast routing device having a multicast routing information base (MRIB) defining a number of enclosing ranges for multicast routes, each enclosing range characterized by a lower boundary and an upper boundary, a method for reducing the number of forwarding states maintained by the multicast routing device, each forwarding state including a source address (S), a group address (G), an inbound list identifying preferred and rejected inbound interfaces for the forwarding state, and an outbound list identifying outbound interfaces for the forwarding state, the method comprising:
- associating with each forwarding state a source address range encompassing at least one source address, wherein a forwarding state having a source address range encompassing all possible source addresses is a default forwarding state, and a forwarding state having a source address range encompassing fewer than all possible source addresses is a non-default forwarding state;
- and
- maintaining the forwarding states such that the source address ranges for all non-default forwarding states are non-overlapping.
A device comprising:
- a plurality of network interfaces;
- a multicast routing information base (MRIB) for storing multicast routing information including a number of enclosing ranges for multicast routes, each enclosing range characterized by a lower boundary and an upper boundary;
- a forwarding table for storing forwarding states, each forwarding state including a source address (S), a group address (G), an inbound list identifying preferred and rejected inbound interfaces for the forwarding state, and an outbound list identifying outbound interfaces for the forwarding state;
- routing protocol logic operably coupled to determine multicast routes utilizing the plurality of network interfaces and store the multicast routes in the MRIB;
- and
- table management logic responsive to multicast routing information obtained from the MRIB, the routing protocol logic, and the plurality of network interfaces, the table management logic operably coupled to associate with each forwarding state a source address range encompassing at least one source address, wherein a forwarding state having a source address range encompassing all possible source addresses is a default forwarding state and a forwarding state having a source address range encompassing fewer than all possible source addresses is a non-default forwarding state, and to maintain the forwarding states such that the source address ranges for all non-default forwarding states are non-overlapping.
A program product comprising a computer readable medium having embodied therein a computer program for reducing the number of forwarding states in a multicast routing device, the multicast routing device having a forwarding table for storing forwarding states, each forwarding state including a source address (S), a group address (G), an inbound list identifying preferred and rejected inbound interfaces for the forwarding state, and an outbound list identifying outbound interfaces for the forwarding state, and a multicast routing information base (MRIB) for storing multicast routing information including a number of enclosing ranges for multicast routes, each enclosing range characterized by a lower boundary and an upper boundary, the computer program comprising:
- routing protocol logic operably coupled to determine multicast routes utilizing a plurality of network interfaces and store the multicast routes in the MRIB;
- and
- table management logic responsive to multicast routing information obtained from the MRIB, the routing protocol logic, and the plurality of network interfaces, the table management logic programmed to associate with each forwarding state a source address range encompassing at least one source address, wherein a forwarding state having a source address range encompassing all possible source addresses is a default forwarding state and a forwarding state having a source address range encompassing fewer than all possible source addresses is a non-default forwarding state, and to maintain the forwarding states such that the source address ranges for all non-default forwarding states are non-overlapping.
Dependencies are inferred from the claim text.