Multiplex communications – Pathfinding or routing – Combined circuit switching and packet switching
Reexamination Certificate
2000-01-05
2003-09-02
Vincent, David (Department: 2732)
Multiplex communications
Pathfinding or routing
Combined circuit switching and packet switching
C370S356000
Reexamination Certificate
active
06614785
ABSTRACT:
CROSS-REFERENCE TO APPENDICES
The following appendices are provided in microfiche form and are incorporated herein by reference in their entirety.
The total number of microfiche in Appendix A is 1. The total number of frames in Appendix A is 27.
Appendix B. Software Source Code, “os_lsd.h”. The total number of microfiche in Appendix B is 1. The total number of frames in Appendix B is 5.
Appendix C. Software Source Code, “os_lsd.c”. The total number of microfiche in Appendix C is 1. The total number of frames in Appendix C is 6.
Appendix D. Software Source Code, “ospfLib.c”. The total number of microfiche in Appendix D is 1. The total number of frames in Appendix D is 5.
Appendix E. IETF RFC 1661, “The Point-to-Point Protocol.” The total number of microfiche in Appendix E is 1. The total number of frames in Appendix E is 50.
Appendix F. “Cerent 454 User Documentation” Release 1.0. The total number of microfiche in Appendix F is 4. The total number of frames in Appendix F is 322.
Appendix G. IETF RFC 1583, “OSPF Version 2.” The total number of microfiche in Appendix G is 196. The total number of frames in Appendix G is 2.
Appendix H. IETF RFC 2370, “The OSPF Opaque LSA Option.” The total number of microfiche in Appendix H is 1. The total number of frames in Appendix H is 17.
Appendix I. IETF RFC 1332, “The PPP Internet Protocol Control Protocol (IPCP).” The total number of microfiche in Appendix I is 1. The total number of frames in Appendix I is 16.
Appendix J. IETF RFC 2153, “PPP Vendor Extensions.” The total number of microfiche in Appendix J is 1. The total number of frames in Appendix J is 11.
Appendix K. Software Source Code, “pppvdx.c”. The total number of microfiche in Appendix K is 1. The total number of frames in Appendix K is 8.
Appendix L. Software Source Code “pppvdx.h”. The total number of microfiche in Appendix L is 1. The total number of frames in Appendix L is 4.
COPYRIGHT NOTICE
A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. 37 CFR 1.71(e).
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention generally relates to communications networks and more particularly to networks having routers and circuit switches.
2. Description of the Related Art
It is well known for routers of messages (in a packet-switched network) to communicate with one another in accordance with the Open Shortest Path First (“OSPF”) protocol, which is governed by a standard of the Internet Engineering Task Force (“IETF”). IETF document RFC 1583 (“IETF RFC 1583”), shown in Appendix G, describes OSPF Version 2 and is incorporated herein by reference in its entirety. IETF documents in general, including RFC 1583, are available at the IETF Internet web site “www.ietf.org.” In OSPF, messages containing information about the location of various routers and interconnections among the routers (also called “network topology”) are sent by the routers to one another. Each router maintains and updates a database of network topology information retrieved from such messages, which are also called “Link State Advertisements” (“LSA”). Each router uses the network topology information to determine the shortest path from itself to all other routers in the network.
The OSPF protocol has been enhanced to support a new class of LSA messages called “Opaque LSAs.” Opaque LSAs are described in IETF RFC 2370, shown in Appendix H and incorporated herein by reference in its entirety. Opaque LSAs consist of a conventional LSA header followed by an information field that may be used directly by OSPF or by other applications. Implementation of Opaque LSAs provides an application interface for 1) encapsulating application-specific information in a specific Opaque type, 2) sending and receiving application-specific information, and 3) if required, informing the application of the change in validity of previously received information when topological changes are detected.
SUMMARY OF THE INVENTION
This invention relates to a method and associated apparatus for automatically propagating circuit information in a network. In one embodiment, a network includes multiple circuit switches that are coupled together by communications links (“links”). Information relating to a link coupling two circuit switches is automatically propagated on the network using a protocol which is ordinarily used by routers(“packet routing protocol”) in communicating with other routers. Such link related information includes identifiers assigned to the interfaces coupled by the link. Information which is automatically propagated using the packet routing protocol is used to create and maintain a table describing each operational link connecting two circuit switches. By describing a link to a level of detail which includes the interfaces coupled by the link, the table provides a detailed topology of the circuit switches in the network.
In another embodiment, a router and a circuit switch are in a single network element, the network element being part of a network. The network elements in the network are physically coupled together via the circuit switches included in each network element. Because the router and the circuit switch are in the same network element and coupling between network elements are via the circuit switches, the routers form a packet network that is implemented using the circuit switches that, in turn, form a circuit network. Information relating to the links coupling the circuit switches is automatically propagated using a packet routing protocol. Such information is also used to create and maintain a table which is included in all network elements.
In another embodiment, the links connecting the circuit switches are Synchronous Optical Network (“SONET”) links and the packet routing protocol is OSPF. In one embodiment, the OSPF flooding mechanism is used to automatically propagate circuit information (as opposed to packet network type of information). Such circuit information includes a description of the interfaces coupled to a link and other information relating to the link.
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Information about Tornado for Managed Switches Software from WindRiver Systems' website, www.wrs.com, 4 pages, Oct. 28, 1999.
Bellcore GR-253-CORE Issue 2, Dec. 1995, Revision 2, Jan. 1999, ppgs. 8-1 to 8-8, 8-31 to 8-36.
Anbiah Anix
Baldwin Gary
Huai Jin
Campbell Stephenson Ascolese LLP
Cisco Technology Inc.
Vincent David
LandOfFree
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