(12) United States Patent ao) Patent No.: us 6,438,100 Bi
Halpern et al. (45) Date of Patent: Aug. 20,2002
(54) METHOD AND APPARATUS FOR ROUTING SERVER REDUNDANCY IN A NETWORK HAVING CARRIER SCALE INTERNETWORKING
(75) Inventors: Joel M. Halpern, Leesburg, VA (US);
Zdenek Becka, Washington, DC (US);
Wan Chen, Chevy Chase, MD (US)
(73) Assignee: Alcatel Canada Inc., Kanata (CA)
( * ) Notice: Subject to any disclaimer, the term ol this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.
(21) Appl. No.: 09/368,752
(22) Filed: Aug. 5, 1999
Related U.S. Application Data
(60) Provisional application No. 60/095,752, filed on Aug. 7, 1998.
(51) Int. CI.7 H04L 12/28; H04L 12/46;
H04L 12/56
(52) U.S. CI 370/218; 370/254; 370/397;
370/401; 370/428; 709/203; 709/238; 709/249;
709/252
(58) Field of Search 370/216, 217,
370/218, 254, 255, 256, 389, 395.1, 396, 397, 400, 401, 409, 428, 429; 709/201, 202, 203, 220, 221, 238, 249, 252; 714/1,
2, 3, 4
(56) References Cited
U.S. PATENT DOCUMENTS
5,600,644 A * 2/1997 Chang et al 370/404
5,870,454 A * 2/1999 Dahlen 379/88.14
5,951,649 A * 9/1999 Dobbins et al 709/238
6,005,864 A * 12/1999 Krause 370/395
6,229,813 Bl * 5/2001 Buchko et al 370/412
6,335,926 Bl * 1/2002 Silton et al 370/351
* cited by examiner
Primary Examiner—Alpus H. Hsu
(57) ABSTRACT
A method and apparatus provides greater flexibility, scalability and manageability when multiple services are being supported by a Carrier Scale Internetworking (CSI) system by including processing that detects when connectivity to an Route Server Instance (RSI) host that is supporting an active RSI has lailed and provides a replacement RSI host from a redundancy set. In additional, forwarders (i.e., core forwarder, edge forwarder, and/or delault forwarder), upon detecting a change in the RSI host, connect to the new RSI host. RSI hosts in the redundancy set use a redundancy chain protocol to select the new RSI host to lunction as the active RSI. Note that an RSI host may be a virtual entity on a routing service control point (RSCP) that indicates that this RSI Host has the capability to become an active RSI, wherein an active RSI is an RSI Host that is running the RSI.
32 Claims, 8 Drawing Sheets
