Fast service restoration for lost IGMP leave requests

• US 20040111470A1
• Filed: 12/06/2002
• Published: 06/10/2004
• Est. Priority Date: 12/06/2002
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Alcatel Canada Inc. (Nokia Corporation)
• Inventors: Aboukarr, Bakri, Poulsen, Allan Leslie, Crane, Stephen Elliott
• Granted Patent: US 7,359,939 B2
• Time in Patent Office: Days
• US Class Current: 709/204
• CPC Class Codes: H04L 12/185 with management of multicast group membership
• CPC Class Codes: H04L 12/1877 Measures taken prior to transmission
• CPC Class Codes: H04L 12/2861 Point-to-multipoint connection from the data network to the subscribers
• CPC Class Codes: H04L 12/2883 ATM DSLAM

Abstract

A fast service restoration for a lost IGMP Leave request. The network node does a comparison to determine if Leave messages are lost in transmission from an end-user system to a supporting network node.

Claims

1. A method of managing IP multicast connections in a network having a network node and a plurality of end users, said method comprising the steps of

(a) receiving, at a network node an IGMP Group Join message from an end-user device serviced by the network;

(b) comparing, at the network node, a MAC address, obtained from the Join message, of the end-user device to another MAC address obtained from a previous Join message for which there exists an IP multicast connection to the network node;

(c) initiating, by the network node responsive to a match resulting from the comparison, a GSQ for the group of the matching previous Join request; and

(d) terminating, responsive to a result of the GSQ processing indicating that a connection to the group is no longer needed, the connection to the group.

2. The method defined in claim 1 wherein if there is not enough resources to satisfy the requirements of the Group Join message received (or subsequent Group Join messages), then it may either be ignored, or queued for later processing, once the normal GSQ sequence is complete and resources are available.

3. The invention defined in claim 1 wherein multiple Join-Leave pairs are dealt within rapid succession.

4. In a data communications network having one or more network nodes, said one or more network nodes including digital subscriber line access multiplexers, said network implementing the internet group management protocol (IGMP), said one or more network nodes having means for receiving an IGMF Group Join message from an end-user serviced by said network and comparing the MAC address contained in said Join message of an end-user device to another MAC address obtained from a previous Join message, said network node initiating a group specific query (GSQ) with a group of the matching previous Join requests and said network node terminating the connection to the group in response to the GSQ indicating that a connection to the group is no longer needed.

5. The invention defined in claim 4 wherein said network node includes a digital subscriber line access multiplexer.

6. The system defined in claim 4 wherein said end-use device is a set-top box.