(12) United States Patent (io) Patent No.: US 6,778,492 B2
Charny et al. (45) Date of Patent: Aug. 17,2004
(54) LOAD BALANCING FOR FAST REROUTE BACKUP TUNNELS
(75) Inventors: Anna Charny, Sudbury, MA (US);
Robert James Goguen, Acton, MA
(US); Carol Iturralde, Framingham,
(73) Assignee: Cisco Technology, Inc., San Jose, CA (US)
( * ) Notice: Subject to any disclaimer, the term ol this patent is extended or adjusted under 35 U.S.C. 154(b) by 12 days.
(21) Appl. No.: 10/052,665
(22) Filed: Jan. 17, 2002
(65) Prior Publication Data
US 2004/0052207 Al Mar. 18, 2004
(51) Int. CI.7 H04L 12/28
(52) U.S. CI 370/228
(58) Field of Search 370/217, 228,
370/219, 220, 225, 227
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* cited by examiner
Primary Examiner—Chi Pham
Assistant Examiner—Nhat Do
(74) Attorney, Agent, or Firm—Ritter, Lang & Kaplan LLP (57) ABSTRACT
Load balancing among last reroute backup tunnels in a label switched network is achieved. M backup tunnels may be used to protect N parallel paths. A single backup tunnel may protect multiple parallel paths, saving on utilization of network resources such as router state and signaling information. A single path may be protected by multiple backup tunnels, assuring that bandwidth guarantees are met under failure conditions even when no one backup tunnel with sufficient bandwidth may be found. A packing algorithm is used to associate individual label switched paths (LSPs) with individual backup tunnels. If an LSP cannot be assigned to a backup tunnel, it may be either rejected, or additional bandwidth is allocated to existing backup tunnels, or a new backup tunnel is established.
14 Claims, 6 Drawing Sheets