Autosensing LMI protocols in frame relay networks

• US 5,802,042 A
• Filed: 06/28/1996
• Issued: 09/01/1998
• Est. Priority Date: 06/28/1996
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Systems, Inc.
• Inventors: Fowler, Gregory A., Natarajan, Shankar
• Primary Examiner(s): Hsu, Alpus H.
• Assistant Examiner(s): YAO, KWANG BIN
• Application Number:
  US08/672,674
• Time in Patent Office: 795 Days
• Field of Search: 370/254, 370/255, 370/256, 370/257, 370/258, 370/351, 370/389, 370/400, 370/401, 370/402, 370/465, 370/474, 370/466, 370/467, 395/200.01, 395/200.15, 395/200.16, 395/200.17, 395/200.18, 395/200.2, 395/200.5, 395/200.51, 395/200.52, 395/200.6, 395/200.61 , 395/200.62, 364/240.8, 364/242.94
• US Class Current: 370/255
• CPC Class Codes: H04L 12/2854 Wide area networks, e.g. public data networks
• CPC Class Codes: H04L 69/18 Multiprotocol handlers, e.g. single devices capable of handling multiple protocols
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

The invention provides a method and system for auto-sensing LMI protocols in frame relay networks. When a router is first coupled to a frame relay network, it automatically configures the local management interface (LMI) to use one of a selected set of possible LMI protocols, by generating a set of protocol requests for a plurality of protocols, and by thereafter simultaneously listening for protocol responses from the configuration server. Multiple valid responses from the configuration server are assigned priority in response to which valid response is last to arrive.

Claims

1. A method of configuring a router and a frame relay network switch to use a selected LMI protocol in a frame relay network, said method comprising:

transmitting substantially simultaneously a plurality of requests, one for each of a set of LMI protocols, from said router to said frame relay network switch, said router listening for a response after each request is transmitted;

receiving at least one said request at said frame relay network switch, configuring said frame relay network switch in response to said request according to the protocol associated with said request, and transmitting a response thereto; and

receiving said response at said router and configuring said router in response thereto.

2. A method as in claim 1, wherein said step of transmitting substantially simultaneously a plurality of requests includes the step of setting a timeout for at least one of said plurality of requests.

3. A method as in claim 1, wherein said step of transmitting substantially simultaneously a plurality of requests includes the step of setting a separate timeout for each one of said plurality of requests.

4. A method as in claim 1, wherein said set of LMI protocols comprise an ANSI protocol, an ITU protocol, and an LMI protocol.

5. A method as in claim 1, wherein said step of receiving at least one said request at said frame relay network switch and configuring said frame relay network switch in response to said request includes the steps of:

receiving a first request and configuring said frame relay network switch in response to said first request; and

receiving a second request and reconfiguring said frame relay network switch in response to said second request.

6. A method as in claim 5, wherein said step of receiving a second request occurs after said step of receiving a first request, whereby requests received later take priority over requests received earlier.

7. A method as in claim 1, wherein said step of receiving said response at said router includes the steps of:

listening on a plurality of LMI management channels for said response; and

receiving at least one said response on at least one of said plurality of LMI management channels.

8. A method as in claim 7, wherein said plurality of LMI management channels comprises LMI management channels zero and 1023.

9. A router disposed for coupling to a frame relay network, the router comprising:

means for transmitting substantially simultaneously a plurality of requests, one for each of a set of LMI protocols, from the router to a switch coupled to said frame relay network;

means for receiving a response to said request from said switch, said receiving means responsive to said response after said request is transmitted by said means for transmitting; and

means for configuring the router in response to said response according to the protocol associated with said response.

10. A router as in claim 9, wherein said means for transmitting comprises a timeout for at least one of said plurality of requests.

11. A router as in claim 9, wherein said means for transmitting comprises a separate timeout for each one of said plurality of requests.

12. A router as in claim 9, wherein said set of LMI protocols comprise an ANSI protocol, an ITU protocol, and an LMI protocol.

13. A router as in claim 9, wherein said means for receiving said response comprises

means for listening on a plurality of LMI management channels for said response;

and

means for receiving at least one said response on at least one of said plurality of LMI management channels.

14. A router as in claim 13, wherein said plurality of LMI management channels comprises LMI management channels zero and 1023.