Method and apparatus for controlling the dissemination of routing information on a communication network
First Claim
1. A method of controlling the dissemination of routing information on a communication network without requiring flooding areas to be pre-defined on the communication network, the method comprising the steps of:
- defining a maximum flooding radius for each link state advertisement to be flooded on the network, the maximum flooding radius enabling dissemination of the link state advertisement to be controlled on the network; and
preventing, by each network element on the communication network, link state advertisements from flooding beyond their maximum flooding radius to control the dissemination of routing information by each node on the communication network without requiring flooding areas to be pre-defined on the communication network to thereby implement radius limited dissemination of routing information by each node on the communication network.
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Abstract
The propagation of link state advertisements (LSAs) is limited by defining a propagation radius on the network, measured by sum of link cost, or using another metric. By limiting the distance a LSA will propagate on the network it is possible to limit LSA traffic on the network without defining areas on the network. This eliminates the need to name those areas and designate nodes as belonging to particular areas, which enables the nodes to be added on an ad-hoc basis without a centralized management structure. Additionally, this enables the nodes to be mobile on the network without requiring close monitoring and updating of area affiliation by the nodes. Further, not having areas on the network eliminates the requirement for area border routers to control link state advertisements, reduces or eliminates special intra-area communication protocol exchanges, and avoids potential congestion which may occur in connection with inter-area traffic.
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Citations
14 Claims
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1. A method of controlling the dissemination of routing information on a communication network without requiring flooding areas to be pre-defined on the communication network, the method comprising the steps of:
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defining a maximum flooding radius for each link state advertisement to be flooded on the network, the maximum flooding radius enabling dissemination of the link state advertisement to be controlled on the network; and preventing, by each network element on the communication network, link state advertisements from flooding beyond their maximum flooding radius to control the dissemination of routing information by each node on the communication network without requiring flooding areas to be pre-defined on the communication network to thereby implement radius limited dissemination of routing information by each node on the communication network.
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2. A network topology, comprising:
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a plurality of OSPF routers interconnected in a network, each of said plurality of OSPF routers being configured to define a maximum flooding radius for link state advertisements to be flooded on the network, the maximum flooding radius enabling dissemination of the link state advertisement to be controlled on the network; and each of the plurality of OSPF routers being further configured to prevent link state advertisements from flooding beyond their maximum flooding radius to control the dissemination of routing information by each of the plurality of OSPF routers on the network without requiring flooding areas to be pre-defined on the network, to thereby implement radius limited dissemination of routing information by each of the plurality of OSPF routers on the network, such that not every OSPF router within the an OSPF area receives every Link State Advertisement (LSA). - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10)
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11. A network node, comprising:
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ports interconnected by a switch fabric to enable the network node to communicate on a network; and control logic configured to inspect a link state advertisement received from the network, ascertain link state information from the link state advertisement, determine a relevance of the link state information; and
selectively drop the link state advertisement if the link state information is not relevant;the control logic being further configured to enable the network node to participate in defining a maximum flooding radius for each link state advertisement to be flooded on the network, the maximum flooding radius for a particular link state advertisement enabling dissemination of that particular link state advertisement to be controlled on the network; and the control logic being still further configured to enable the node to prevent link state advertisements from flooding beyond their maximum flooding radius to control the dissemination of routing information by the node on the communication network without requiring flooding areas to be pre-defined on the communication network to thereby implement radius limited dissemination of routing information by the node and a plurality of similarly configured other nodes on the communication network. - View Dependent Claims (12, 13, 14)
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Specification