METHOD AND DEVICE FOR MANAGING MULTICAST GROUPS

• US 20090310609A1
• Filed: 08/24/2009
• Published: 12/17/2009
• Est. Priority Date: 06/26/2007
• Status: Active Grant

• Current Assignee: Media Patents S.L.
• Original Assignee: Media Patents S.L.
• Inventors: Fernandez Gutierrez, Alvaro
• Granted Patent: US 8,094,602 B2
• Time in Patent Office: Days
• US Class Current: 370/390
• CPC Class Codes: H04L 12/185 with management of multicast group membership

Abstract

A method for managing multicast traffic in a data network, and devices using said method. The hosts store for each multicast group an included source record and an excluded source record, and the network interfaces of the hosts send to the router a message containing information about the included source record and information about the excluded source record. The router also stores for each multicast group an included source record and an excluded source record, and updates them when it receives through its network interface a message from the hosts containing information about an included source list and/or information about an excluded source list. The devices are a router, host equipment and network equipment compatible with the method.

Claims

1. A router having at least one downstream network interface situated in a data network system between sources that send multicast packets to at least one multicast group address and one or more hosts that request data from the multicast group address and the sources, the router communicates with the one or more hosts via a communications protocol based on the IGMP (Internet Group Management Protocol) or the MLD (Multicast Listener Discovery) protocol and stores for each downstream network interface and multicast group address at least one IGMP or MLD INCLUDE source record containing information about include source lists derived by data requests made by the one or more hosts and at least one IGMP or MLD EXCLUDE source record containing information about exclude source lists derived by data requests made by the one or more hosts.

2. A router according to claim 1, wherein the INCLUDE source record stored in the router contains the union of all the include source lists requested from all the hosts.

3. A router according to claim 1, wherein the EXCLUDE source record stored in the router contains the intersection of all the exclude source lists requested from all the hosts.

4. A router according to claim 1, wherein one INCLUDE source record and one EXCLUDE source record is stored in the router, the INCLUDE source record containing the union of all the source lists requested from all the hosts and the EXCLUDE source record containing the intersection of all the exclude source lists requested from all the hosts.

5. A router according to claim 1, wherein the at least one INCLUDE source record for a network interface and multicast group address comprises (multicast-address, INCLUDE, {source list and timers}) and the at least one EXCLUDE source record comprises (multicast-address, EXCLUDE, {source list and timers}), where {source list and timers} comprise a list of elements {source-address and source-timer}, and where source-address comprises the source IP address, and where source-timer comprises a timer associated to the source.

6. A router according to claim 1, wherein the router contains executable instructions for updating the at least one INCLUDE source record and the at least one EXCLUDE source record upon receiving a state message or change of state message originating from the one or more of hosts.

7. A router according to claim 1, wherein the router is capable of receiving a state message originating from one or more hosts that includes instructions about the method the router must apply to set up routing trees from the sources to the router.

8. A router according to claim 1, wherein the router stores executable instructions for (1) keeping, for each downstream network interface and multicast group address, at least two separate records:

the INCLUDE source record and the EXCLUDE source record, and (2) updating the INCLUDE source record and the EXCLUDE source record, for each multicast group address, when the router receives, through its downstream network interface, a message containing information about an include source list and information about an exclude source list originating from one or more of the hosts.

9. A router according to claim 1, wherein for a multicast group address the router includes an upstream network interface that requests the data from the sources via other routers situated within a routing tree between the sources and the router, the upstream network interface communicates with the other routers via a multicast routing protocol between routers to request the data from the sources using the information in the INCLUDE source record and the information in the EXCLUDE source record to permit a direct connection with the sources through a shortest path tree of the routing tree.

10. A router according to claim 9, wherein the multicast routing protocol between routers is a version of a PIM (Protocol Independent Multicast) protocol.

11. A router according to claim 1, wherein for a multicast group address the router includes an upstream network interface that requests the data from the sources via other routers which include a Rendezvous Point Router, the other routers situated within a routing tree between the sources and the router, the routing tree including rendezvous point trees (RPT) and shortest path trees (SPT) for the sources, the upstream network interface communicates with the other routers via a multicast routing protocol between routers to request the data from the sources using the information in the INCLUDE source record and the information in the EXCLUDE source record to permit a direct connection with the sources via the shortest path trees without the need to use the rendezvous point trees.

12. A router according to claim 11, wherein the multicast routing protocol between routers is a version of a PIM (Protocol Independent Multicast) protocol.

13. The router of claim 1, wherein upon receiving in a downstream network interface an IS_IN(x) type message for a multicast group address no EXCLUDE source records for the multicast group are modified.

14. The router of claim 1, wherein upon receiving in a downstream network interface an IS_EX(x) type message for a multicast group address no INCLUDE source records are modified.

15. The router according to claim 1, wherein the exclude source lists include a Requested List and an Exclude List, for each downstream interface and multicast group address the router first transmits to the hosts data from the sources in the include source lists and then transmits to the hosts data from all the remaining sources except those sources from the Exclude List.

16. A router according to claim 1, wherein the router is configured to receive messages originating from the one or more hosts requesting the router to stop sending data from a multicast group address and a source and to send Group-And-Source-Specific Query type messages to the one or more hosts, the router storing executable instructions for determining whether one or more other hosts are receiving data from the multicast group address and source upon receiving the stop request using the at least one INCLUDE source record and the at least one EXCLUDE source record and to continue sending data from the multicast group address and source to the one or more other hosts without sending a Group-And-Source-Specific Query messages to the one or more other hosts receiving data from the multicast group address and source.