Method and system for creating small group multicast over an existing unicast packet network
AssigneeInternational Business Machines Corporation
InventorsRichard Harold Boivie, Kiyoshi Maruyama
Life of this patent
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Abstract
A routing table for use with a router in a world-wide network, includes an existing routing table with a multicast-destination (MD) column.
Claims36
A routing table in a router in a wide-area packet-switched network, said routing table comprising:
- a plurality of conventional routing table columns, including columns for destination D, next-node NN, and distance to destination d(D);
- and
- a multicast destination (MD) column having a capability to list a unicast address.
A routing system, including:
- a routing unit for updating a next-node (NN) column of a routing table and for routing unicast packets by referencing the NN column of the routing table;
- a packet regeneration unit for referencing the multicast destination (MD) column of the routing table and for selectively creating copies of at least one of unicast and multicast packets;
- and
- a multicast-destination (MD) discovery unit for updating the MD column of the routing table.
A method of processing a packet, comprising:
- receiving a packet at a router;
- checking, by said router, if the packet's destination is itself or not;
- if the packet's destination is not the router, then routing said packet in a predetermined manner;
- and
- if the received packet's destination is itself and if the packet is a multicast packet such that MC=1, then forwarding the packet to a packet regeneration process.
A method for extending a routing table, comprising:
- adding a multicast-destination (MD) column to an existing routing table, wherein said MD column represents that, for each destination row in the routing table, there is an MD entry for use by a multicast-capable router when it has received a multicast packet for routing.
A method of using a routing table, comprising:
- referencing a column (MD) of a routing table to perform a packet regeneration and routing process,
- wherein said MD column represents that, for each destination row in the routing table, there is an MD entry for use by a multicast-capable router when it has received a multicast packet for routing.
A method of learning of a nearest multicast-capable router by a source node, comprising:
- running a traceroute to a destination;
- and
- sending each node along the traced route a multicast packet having the form (S,Dt,1(S)), where Dt is a node along the traced route, and wherein such sending is performed first from a nearest node Dt.
A method of regenerating a packet in a router in a network, comprising:
- for a packet having a form of (S,Dmc,1(D1,D2, . . . ,Dk)), for each destination, D1 through Dk, finding the multicast destination (MD) from a routing table;
- for those destinations having the same MD, generating a multicast packet having a form (S,MD,1(destinations)) with remaining fields in the packet the same as an originally received packet;
- and
- for each of the destinations where the MD is the same as the destination such that MD=D, creating a unicast packet of the form (S, D) with remaining fields in the packet the same as the originally received packet.
A programmable storage medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform a method of extending an existing routing table, comprising:
- including a multicast-destination (MD) column in said routing table such that the MD column is for packet regeneration.
A programmable storage medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform a method of processing a packet, said method comprising:
- receiving a packet at a router;
- checking, by said router, if the packet's destination is itself or not;
- if the packet's destination is not the router, then routing said packet in a predetermined manner;
- and
- if the received packet's destination is itself and if an entry in a routing table indicates that the packet is a multicast packet (e.g., MC=1), then forwarding the packet to a packet regeneration process.
A programmable storage medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform a method of regenerating a packet in a router in a network, said method comprising:
- for a packet having a form of (S,Dmc,1(D1,D2, . . . ,Dk)), for each destination, D1 through Dk, finding the multicast destination (MD) from a routing table;
- for those destinations having the same MD, generating a multicast packet having a form (S,MD,1(destinations)) with remaining fields in the packet the same as an originally received packet;
- and
- for each of the destinations where the MD is the same as the destination such that MD=D, creating a unicast packet of the form (S, D) with remaining fields in the packet the same as the originally received packet.
A programmable storage medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform a method of learning of a nearest multicast-capable router by a source node, said method comprising:
- running a traceroute to a destination;
- and
- sending each node along the traced route a multicast packet having the form (S,Dt,1(S)), where Dt is a node along the traced route, and wherein such sending is performed first from a nearest node Dt.
Dependencies are inferred from the claim text.