System and method for hierarchical multicast routing in ATM networks
First Claim
1. A method for multicasting cells in a communications network, said communications network including a plurality of nodes coupled to one another by links, said method comprising the steps of:
- dividing said communications network into a hierarchical arrangement of peer groups including logical peer groups representative of a collection of nodes at a lower level of said hierarchical arrangement, wherein a peer group includes at least one of said nodes therein;
building a multicast tree for a multicast group of nodes in said network which includes all participant nodes involved in a multicast, wherein a participant node is either a sender or receiver of data for said multicast group, said step of building including the steps of;
selecting core nodes for each of said peer groups within said multicast group, wherein a node wanting to become part of said multicast group must register with a core node in its peer group;
flooding core node identity information locally within each of said peer groups including said logical peer groups, wherein said nodes of a peer group need only maintain said identity information about said core nodes of direct ancestor peer groups; and
selecting a peer group leader for each of said peer groups in said network for aggregating topology information of nodes in said peer group and flooding said topology information in higher level peer groups, said peer group leader flooding collected topology information from higher level peer groups into lower level peer groups, said collected topology information including a list of logical core nodes of ancestor peer groups for each said multicast group, wherein said peer group leader may be a different node than said core node in a peer group,wherein said cells are able to be efficiently multicast by way of said multicast tree to said nodes in said multicast group.
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Abstract
The present invention extends the PNNI protocols to support hierarchical multicast routing and signaling for ATM networks. The invention utilizes an extension to a core-based tree algorithm. Instead of a single core node, core nodes are maintained in each peer-group and at each level of the hierarchy. The advantage of this is that one single core node is not overloaded. Additionally, this increases fault-tolerance because there are no single points of failure. As would be understood, the present invention is highly scaleable because of the hierarchical nature of PNNI. In addition, the scheme supports multiple senders and dynamic membership changes to the multicast group. Quality of service requirements can be negotiated during connection setup and are guaranteed during the course of the connection. Though some additional topological information has to be flooded in the peer-groups to compute efficient multicast routes, the overheads to the connection management are minimal. The multicast tree is built incrementally and the cost of the tree is comparable to the cost of the Steiner Tree computed using some standard heuristics.
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Citations
23 Claims
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1. A method for multicasting cells in a communications network, said communications network including a plurality of nodes coupled to one another by links, said method comprising the steps of:
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dividing said communications network into a hierarchical arrangement of peer groups including logical peer groups representative of a collection of nodes at a lower level of said hierarchical arrangement, wherein a peer group includes at least one of said nodes therein; building a multicast tree for a multicast group of nodes in said network which includes all participant nodes involved in a multicast, wherein a participant node is either a sender or receiver of data for said multicast group, said step of building including the steps of; selecting core nodes for each of said peer groups within said multicast group, wherein a node wanting to become part of said multicast group must register with a core node in its peer group; flooding core node identity information locally within each of said peer groups including said logical peer groups, wherein said nodes of a peer group need only maintain said identity information about said core nodes of direct ancestor peer groups; and selecting a peer group leader for each of said peer groups in said network for aggregating topology information of nodes in said peer group and flooding said topology information in higher level peer groups, said peer group leader flooding collected topology information from higher level peer groups into lower level peer groups, said collected topology information including a list of logical core nodes of ancestor peer groups for each said multicast group, wherein said peer group leader may be a different node than said core node in a peer group, wherein said cells are able to be efficiently multicast by way of said multicast tree to said nodes in said multicast group. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A shared communications network for multicasting cells, said communications network including a plurality of nodes coupled to one another by links, said network comprising:
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a hierarchical arrangement of peer groups making up said communications network, wherein a peer group includes at least one of said nodes therein; one or more multicast trees for a multicast group of nodes in said network, which multicast trees include all participant nodes involved in a multicast, wherein a participant node is either a sender or receiver of data for said multicast group; a core node selected for each of said peer groups within said multicast group, wherein a node wanting to become part of said multicast group must register with said core node in its peer group, wherein core node identity information is flooded locally within each of said peer groups, and said nodes of a peer group need only maintain said identity information about said core nodes of direct ancestor peer groups; and a peer group leader for each of said peer groups in said network for aggregating topology information of nodes in said peer group and flooding said topology information in higher level peer groups, wherein a list of logical core nodes of ancestor peer groups is flooded in a peer group by each said peer group leader, wherein said peer group leader may be a different node than said core node, wherein said cells are able to be efficiently multicast by way of said multicast tree to said nodes in said multicast group. - View Dependent Claims (22)
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23. A method for multicasting cells in a communications network, said communications network including a plurality of nodes coupled to one another by links, said method comprising the steps of:
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dividing said communications network into a hierarchical arrangement of peer groups, wherein a peer group includes at least one of said nodes therein; building a multicast tree for a multicast group of nodes in said network which includes all participant nodes involved in a multicast, wherein a participant node is either a sender or receiver of data for said multicast group, said step of building including the steps of; selecting core nodes for each of said peer groups within said multicast group, wherein a node wanting to become part of said multicast group must register with a core node in its peer group; flooding core node identity information locally within each of said peer groups, wherein said nodes of a peer group need only maintain identity information about said core nodes of direct ancestor peer groups; and selecting a peer group leader for each of said peer groups in said network for aggregating topology information of nodes in said peer group and flooding said topology information in higher level peer groups, wherein a list of logical core nodes of ancestor peer groups is flooded in a peer group by each said peer group leader.
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Specification