Patent ID: 7002906
Filing Date: 2006-02-21
Classification: H04L

Abstract:
1. In an Asynchronous Transfer Mode (ATM) system composed of at least a first data network ( 10 ) having a plurality of switching nodes interconnected by connection lines and including end switching nodes each being connected to at least a Data Transmission equipment (DTE) and being used either as an entry border node ( 22 ) when it is connected to a source DTE ( 18 ) or an exit border node ( 28 ) when it is connected to a destination DTE ( 20 ), said first data network using a routing protocol of the type wherein a best route between a source DTE and a destination DTE is determined in a control point associated with said entry border node to which is connected said source DTE and wherein a set-up message is sent by said entry border node, and a second data network ( 12 ) including at least one DTE to be used as destination DTE in an exchange of data with a source DTE connected to said first data network and being interconnected with said first data network by means of at least two Interim Inter Switch Protocol (IISP) links ( 14 , 16 ) not supporting said routing protocol, the at least two IISP links not supporting said routing protocol connecting switching nodes of the first data network with switching nodes of the second data network; method for extending the crankback procedure over all said system comprising: when the a switching node of said first data network receives a clearing message on one of said IISP links indicating that said set-up message has been rejected because said best route is blocked anywhere in said second data network, said switching node building a crankback information element to be added to said clearing message, said crankback information element and said clearing message then transmitted to said entry border node causing said entry border.