Method of preventing overlapping branches in point to multipoint calls in PNNI networks

• US 6,262,984 B1
• Filed: 05/12/1998
• Issued: 07/17/2001
• Est. Priority Date: 05/12/1998
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: 3Com Corporation (HP Inc.)
• Inventors: Rochberger, Haim
• Primary Examiner(s): Hsu, Alpus H.
• Assistant Examiner(s): NGUYEN, BRIAN D
• Application Number:
  US09/076,687
• Time in Patent Office: 1,162 Days
• Field of Search: 370/395, 370/396, 370/397, 370/400, 370/410, 370/254, 370/351, 370/355, 370/356, 370/230, 370/231, 370/256, 370/408, 370/432
• US Class Current: 370/395.2
• CPC Class Codes: H04L 2012/562 Routing
• CPC Class Codes: H04L 2012/5621 Virtual private network [VPN]; Private-network - network-interface (P-NNI)
• CPC Class Codes: H04L 2012/563 Signalling, e.g. protocols, reference model
• CPC Class Codes: H04L 2012/5642 Multicast/broadcast/point-multipoint, e.g. VOD
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/04 Interdomain routing, e.g. hierarchical routing
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

A method that provides a solution to the problem of overlapping branches in a point to multipoint call. The method is suitable for both Leaf Initiated Joins (LIJ) and existing point to multipoint call. The method has applications when adding a new leaf to an already existing point to multipoint connection and where the ROOT node has a corrupted point to multipoint view of the network. The method includes the overlapping node realizing that it is an overlapping node whereby it continues with the establishment of the downstream path in a conventional manner. The overlapping node then waits for the SETUP/ADD PARTY CONNECT to be received before continuing. Once the CONNECT is received, the overlapping node establishes an end point reference path to the point to multipoint root node over existing branches. The new call segments are established and the overlapping segments are then trimmed from the tree.

Claims

1. In an Asynchronous Transfer Mode (ATM) network having a plurality of nodes, a method of removing overlapping branches created when a leaf node is added to an already established point to multipoint call whereby a root node calculates a route for the new leaf node utilizing a corrupted point to multipoint view which results in the establishment of one or more overlapping nodes, a node being an overlapping node when it receives ingress streams from two different nodes for the same point to multipoint call, thus creating an overlapping branch between said overlapping node and the adjacent ingress node along the route calculated for said new leaf node, said method comprising the steps of:

recognizing that the route calculated by said root node for adding a new leaf node to said point to multipoint call creates one or more overlapping nodes on one or more overlapping branches;

establishing a downstream path from the overlapping node to the new leaf node to be added;

receiving a confirmation from the new leaf node by one of said one or more overlapping nodes that is closest to the new leaf node;

establishing an end point reference path from the overlapping node to the root node over previously established point to multipoint branches, thus creating a new path to the new leaf node that does not create any overlapping nodes; and

removing all overlapping branches from the point to multipoint call.

2. The method in accordance with claim 1, wherein the step of recognizing utilizes a Network Call Correlation Identifier (NCCI) generated by the root node.

3. The method in accordance with claim 1, wherein the step of recognizing utilizes a global unique identifier in determining that a node is an overlapping node.

4. The method in accordance with claim 1, wherein the step of recognizing comprises the steps of:

receiving a call setup message for a point to multipoint call;

comparing a Network Call Correlation Identifier (NCCI) in the setup message with NCCIs previously received; and

declaring an overlapping node condition if a match is found.

5. The method in accordance with claim 1, wherein the step of establishing a downstream path comprises the step of sending an add party message to a next node along said calculated route if the next node is part of an existing point to multipoint call.

6. The method in accordance with claim 1, wherein the step of establishing a downstream path comprises the step of sending a setup message to a next node along said calculated route if the next node is not part of an existing point to multipoint call.

7. The method in accordance with claim 1, wherein the step of receiving comprises the step of receiving a CONNECT message returned by the leaf node.

8. The method in accordance with claim 1, wherein the step of establishing an end point reference path comprises the steps of:

receiving a call confirmation message;

generating a unique overlap leaf reference number;

sending a leaf setup request message in an upstream direction on an input port associated with the already established point to multipoint branch, said leaf setup message including said overlap leaf reference number and a designated transmit list;

forwarding said leaf setup request message to said root node wherein each node along the path in the upstream direction including said root node adds itself to said designated transit list;

sending an add party message downstream to said overlapping node so as to create a new path to said new leaf node, said add party message including said overlap leaf reference number and said designated transit list;

receiving said add party message at said overlapping node and searching for a match of said overlap leaf reference number;

configuring said overlapping node for said new path of said point to multipoint call;

sending an add party connect message upstream to said root node; and

configuring said root node to use said new path in response to receiving said add party connect message.

9. The method in accordance with claim 1, wherein the step of removing all overlapping branches comprises the steps of:

sending an add party reject message upstream on an overlapping branch if the overlapping node is part of an existing point to multipoint call;

sending a release message upstream on the overlapping branch if the overlapping node is not part of an existing point to multipoint call;

releasing any existing overlapping branches on the call path from said overlapping node to said root node;

configuring said root node to utilize said new path rather than the path that includes one or more overlapping branches; and

sending an add party connect message to a root user connected to said root node.