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Dynamically controlled routing of calls in intelligent networks

  • US 5,930,348 A
  • Filed: 03/20/1997
  • Issued: 07/27/1999
  • Est. Priority Date: 03/20/1997
  • Status: Expired due to Term
First Claim
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1. A method of routing calls dynamically in a telecommunications network comprising a plurality of switching units and a central computer unit having access to a routing database, the switching units being interconnected by links comprising trunk groups and connected to the central computer unit by a data communication system, each switching unit having call processing software including triggers for initiating queries to the central computer unit during call processing, the method comprising the steps of:

  • at a first switching unit;

    responding to a destination address in a call to attempt to route a call to a destination switching unit via a direct link and,in the event that the attempt is unsuccessful or there is no direct link, issuing to the central computer unit a query message containing the destination address;

    at the central computer unit;

    where the direct link exists but the attempt to use it was unsuccessful, responding to the query message by (i) identifying from the query message the link attempted unsuccessfully, (ii) updating the routing database to identify the link as unavailable for a predetermined period of time;

    whether the query resulted from a lack of a direct link or an unsuccessful attempt to route via an existing direct link, (iii) determining at least one alternative route for the instant call using a tandem switching unit, (iv) compiling a return message including a network address for the tandem switching unit and (v) transmitting the return message to the first switching unit;

    at the first switching unit;

    routing the call via a direct link from the first switching unit to the tandem switching unit; and

    at the tandem switching unit;

    attempting to complete the call by routing the call via a direct link from the tandem switching unit to the destination switching unit;

    in the event that the tandem switching unit cannot complete the call via the third-direct link from the tandem switching unit to the destination switching unit,at the tandem switching unit;

    sending to the central computer unit a second query message including said destination address,at the central computer,responding to the second query message by (vi) identifying from the query message the direct link that the tandem switching unit attempted unsuccessfully, (vii) updating the routing database to identify such direct link as unavailable, while maintaining as unavailable the direct link first attempted by the first switching unit;

    (viii) determining at least one second alternative route for the instant call using a second tandem switching unit, (ix) compiling a return message including a network address for the tandem switching unit and (x) transmitting the return message to the first tandem switching unit;

    at the first tandem switching unit;

    routing the call via a direct link from the first tandem switching unit to the second tandem switching unit; and

    at the second tandem switching unit,attempting to route the call via a direct link from the second tandem switching unit to the destination switching unit.

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