5,659,601 8/1997 Cheslog 379/114
5,675,636 10/1997 Gray 379/114
5,748,718 5/1998 Manicone 379/114
5,781,620 7/1998 Montgomery et al 379/114
5,790,643 8/1998 Gordon et al 379/114
5,799,072 8/1998 Vulcan et al 379/114
5,802,502 9/1998 Gell et al 379/114
5,915,214 6/1999 Reece et al 379/114
5,930,343 7/1999 Vasquez 379/114
[54] LEAST COST ROUTING WITH REPEATED SEARCHES FOR LOWER COST ROUTE
[75] Inventor: Takashi Wakamatsu, Tokyo, Japan
[73] Assignee: NEC Corporation, Tokyo, Japan
[21] Appl. No.: 09/261,746
[22] Filed: Mar. 3, 1999
[30] Foreign Application Priority Data
Mar. 3, 1998 [IP] lapan 10-066007
[51] Int. CI.7 H04M 15/00; H04M 7/00
[52] U.S. CI 379/114; 379/115; 379/220;
379/221
[58] Field of Search 379/112, 111,
379/113, 114, 115, 121, 127, 128, 219, 220, 221, 67.1, 88.12; 455/405, 406
[56] References Cited
U.S. PATENT DOCUMENTS
5,027,388 6/1991 Bradshaw et al 379/114
5,515,425 5/1996 Penzias et al 379/114
5,606,602 2/1997 lohnson et al 379/114
Primary Examiner—Paul N Loomis
Assistant Examiner—Rexford Barnie
Attorney, Agent, or Firm—-Young & Thompson
[57] ABSTRACT
In a communications network, a database is searched for a least cost route in response to a call request Irom a subscriber, and a connection is established along the least cost route between the calling subscriber and a called subscriber. For the duration ol the call, the database is repeatedly searched for a route having a cost lower than the cost ol a previously determined route. II the route ol lower cost is detected, a new connection is established along the lower cost route, instead ol the currently established connection.
14 Claims, 4 Drawing Sheets
