[54] CONTROL METHOD AND APPARATUS FOR PATH SWITCHING IN RING NETWORK
[75] Inventors: Yoshihiro Ashi; Masahiro Takatori. both of Yokohama, Japan
[73] Assignee: Hitachi, Ltd., Tokyo, Japan
[21] Appl. No.: 534,938
[22] Filed: Sep. 28,1995
[30] Foreign Application Priority Data
Sep. 29, 1994 [JP] Japan 6-235251
[51] Int CI.6 H04J 3/14
[52] U.S. CI 370/244; 370/248
[58] Field of Search 370/16.1, 16, 60,
370/60.1, 360, 389, 392, 409, 241, 242, 244, 248, 250; 371/11.2, 20.1; 359/110,
110.1
[56] References Cited
U.S. PATENT DOCUMENTS
5,003,531 3/1991 Farinholt et al 370/16.1
5,093,824 3/1992 Coan et al 370/16
5,187,706 2/1993 Frankeletal 370/16.1
5,278,824 1/1994 Kremer 370/15
5,307,353 4/1994 Yamashita et al 371/11.2
5,341,364 8/1994 Marra et al 370/16.1
5,406,401 4/1995 Kremer 359/110
5,446,725 8/1995 Ishiwatari 370/16.1
OTHER PUBLICATIONS
Bellcore Technical Advisory, TA-NWT-001230, Issue 3, Apr. 1993, Sonet Bidirectional Line-Switched Ring Equipment Generic Criteria.
A method of switching a route path of a ring network having a plurality of route paths for signal transmission, in which a transmission station on a transmission side transmits information of a same content to said plurality of route paths, a transmission station on a reception side selects one of the plurality of route paths, and a failure on the selected route path is automatically retrieved. The method includes the steps of: monitoring whether a signal received on each route path is normal or not; loading failure information as a path status identifier in a predetermined field of the signal received on each route path, the failure information indicating whether the monitoring step has detected a failure; and selecting one of the plurality of route paths in accordance with the failure information and predetermined logic.
29 Claims, 9 Drawing Sheets
