Method and apparatus for providing resource discovery using multicast scope

• US 6,426,945 B1
• Filed: 10/06/1998
• Issued: 07/30/2002
• Est. Priority Date: 10/06/1998
• Status: Expired due to Term

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Telecommunications Oy (Nokia Corporation)
• Inventors: Sengodan, Senthil
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): HYUN, SOON D
• Application Number:
  US09/167,933
• Time in Patent Office: 1,393 Days
• Field of Search: 370/230, 370/235, 370/260, 370/262, 370/443, 370/254, 370/312, 370/352, 370/353, 370/354, 370/355, 370/356, 370/465, 370/401, 370/402, 370/466, 370/390, 370/408, 370/238, 370/238.1, 370/255, 370/256, 370/400, 709/223, 709/224, 709/225, 709/226, 709/227, 709/228, 709/229, 709/239, 709/241
• US Class Current: 370/238
• CPC Class Codes: H04L 12/64 Hybrid switching systems
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04L 45/20 Hop count for routing purposes, e.g. TTL
• CPC Class Codes: H04L 45/26 Route discovery packet
• CPC Class Codes: H04L 45/48 Routing tree calculation

Abstract

A method and apparatus for providing resource discovery using multicast scope selection is disclosed. The method includes the discoverer sending a first request message having a first selected scope to a known multicast group, setting a timer after the first request message is sent, detecting whether a confirm message is received from an endpoint before the timer expires, terminating when a confirm message is received from an endpoint prior to the expiration of the timer, determining whether a scope increase is allowed when a confirm message is not received from an endpoint before the expiration of the timer, terminating when a scope increase is not allowed, increasing the scope to the second selected scope when a scope increase is allowed, resetting the timer and sending a second request message having the second selected scope when a confirm message is not received from an endpoint in response to the first request message, the second selected scope being greater than the first selected scope.

Claims

1. A method for providing resource discovery comprising:

sending a first request message having a first selected scope;

analyzing whether a confirm message is received in response to the first request message;

sending a second request message having a second selected scope when a confirm message is not received in response to the first request message, the second selected scope being greater than the first selected scope; and

wherein the request message further comprises a threshold hop count for avoiding the propagation of a duplicate request message from a node receiving the request message.

2. The method of claim 1 further comprising:

comparing the threshold hop count to the scope;

preventing a response to the request message when the scope is greater than the threshold hop count; and

responding to the request message when the scope is not greater than the threshold hop count.

3. A method for locating an endpoint for setting up a connection, the method comprising:

sending a first request message having a first selected scope to a known multicast group;

setting a timer after the first request message is sent;

detecting whether a confirm message is received from an endpoint before the timer expires;

terminating when a confirm message is received from an endpoint prior to the expiration of the timer;

determining whether a scope increase is allowed when a confirm message is not received from an endpoint before the expiration of the timer;

terminating when a scope increase is not allowed;

increasing the scope to the second selected scope when a scope increase is allowed;

resetting the timer;

sending a second request message having the second selected scope when a confirm message is not received from an endpoint in response to the first request message, the second selected scope being greater than the first selected scope; and

wherein the request message further comprises a threshold hop count for limiting the propagation of the request message in the multicast tree.

4. The method of claim 3 further comprising:

comparing the threshold hop count to the scope;

preventing a response to the request message when the scope is greater than the threshold hop count; and

responding to the request message when the scope is not greater than the threshold hop count.

5. An article of manufacture for providing resource discovery using multicast scope selection, the article of manufacture comprising a computer readable medium having instructions for causing a processor to locate a resource for establishing a connection thereto according to a method, the method comprising:

sending a first request message having a first selected scope;

analyzing whether a confirm message is received in response to the first request message;

sending a second request message having a second selected scope when a confirm message is not received In response to the first request message, the second selected scope being greater than the first selected scope; and

wherein the request message further comprises a threshold hop count for limiting the propagation of the request message in the multicast tree.

6. The article of manufacture of claim 5 further comprising:

comparing the threshold hop count to the scope;

preventing a response to the request message when the scope is greater than the threshold hop count; and

responding to the request message when the scope is not greater than the threshold hop count.

7. A discoverer, comprising:

a discovery unit;

an application, operatively coupled to the discovery unit, the application sending a notification to the discovery unit for locating an endpoint application;

wherein the discovery unit sends a first request message having a first selected scope to a multicast group, analyzes whether a desired confirm message is received in response to the first request message; and

sends a second request message having a second selected scope when a desired confirm message is not received in response to the first request message, the second selected scope being greater than the first selected scope; and

wherein the request message further comprises a threshold hop count for forbidding the propagation of duplicate response messages in the multicast tree.