Patent EP0550180A2 successfully refreshed from Google Patents.
EP0550180A2
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EP
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Rerouting in a distributed telecommunication system
Assignee: AT&T Inc
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Filing: 1992-12-10
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Granted: —
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Expires: 2012-12-10
Abstract
Abstract Routing calls using a new protocol message which is a redirect message in a telecommunication system having a number of switching nodes to avoid circular paths among the switching nodes and for rerouting calls in the event of failures or overload conditions. During the establishment of a call from an originating switching node to a destination switching node where the call path has already been setup from the originating switching node through an intermediate switching node, a switching node is responsive to a setup message from the intermediate switching node requesting extension of the call path through the switching node to determine if such an extension would create a circular path. If circular path would be created, the switching node redirects the call (by using the redirect message) back to the intermediate switching node and indicates in that message to which switching node the call path should be extended. In response to the redirect message, the intermediate switching node reroutes the call path. Further, the redirect message entirely removes the call path between the switching node and intermediate switching node.
Inventors
- 👤 Bruce Merrill Bales
- 👤 Robert Louis Crumpley
- 👤 Sandra Sue North
- 👤 Stephen Max Thieler
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 09:52
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/0016; H04M; H04M3/00; H04M3/42; H04M3/54; H04M3/545; H04Q2213/00; H04Q2213/1307; H04Q2213/13141; H04Q2213/13146; H04Q2213/13166; H04Q2213/13176; H04Q2213/13217; H04Q2213/13383
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
142 words
A method for controlling the routing of calls within a telecommunication switching system having a plurality of switching nodes interconnected by links, comprising the steps of: determining by a switching node in response to a setup message to extend a call path being set up between a originating and destination switching nodes through the switching node where the call path is already setup through a subset of the switching nodes that setting up the call path through the switching node would result in the call path having to extend through one of the subset of the switching nodes a second time before the call path terminated on the destination switching node; communicating a redirect message by the switching node back on the call path to the subset of switching nodes to deny the extension of the call path through the switching node.
Claim 2
Independent Claim
142 words
A method for controlling the routing of calls within a telecommunication switching system having a plurality of switching nodes interconnected by links, comprising the steps of: determining by a switching node in response to a setup message to extend a call path being set up between a originating and destination switching nodes through the switching node where the call path is already setup through a subset of the switching nodes that setting up the call path through the switching node would result in the call path having to extend through one of the subset of the switching nodes a second time before the call path terminated on the destination switching node; communicating a redirect message by the switching node back on the call path to the subset of switching nodes to deny the extension of the call path through the switching node.
Claim 3
Dependent Claim
39 words
The method of claim 1 wherein the step of communicating comprises the steps of identifying another switching node to which the call path should be extended; and inserting the information identifying the other switching node into the redirect message.
Claim 4
Dependent Claim
26 words
The method of claim 2 wherein the step of identifying the other switching node comprises the step of searching internal tables stored by the switching node.
Claim 5
Dependent Claim
62 words
The method of claim 2 further comprises the step of inserting into the setup message by each of the subset of switching nodes information identifying each of the subset of switching nodes; and the step of determining comprises the step of searching the information identifying each of the subset of switching nodes to determine the one of the subset of switching nodes.
Claim 6
Independent Claim
143 words
An apparatus for controlling the routing of calls within a telecommunication switching system having a plurality of switching nodes interconnected by links, comprising: means in a switching node for determining in response to a setup message to extend a call path being set up between a originating and destination switching nodes through the switching node where the call path is already setup through a subset of the switching nodes that setting up the call path through the switching node would result in the call path having to extend through one of the subset of the switching nodes a second time before the call path terminated on the destination switching node; means in the switching node for communicating a redirect message back on the call path to the subset of switching nodes to deny the extension of the call path through the switching node.
Claim 7
Independent Claim
143 words
An apparatus for controlling the routing of calls within a telecommunication switching system having a plurality of switching nodes interconnected by links, comprising: means in a switching node for determining in response to a setup message to extend a call path being set up between a originating and destination switching nodes through the switching node where the call path is already setup through a subset of the switching nodes that setting up the call path through the switching node would result in the call path having to extend through one of the subset of the switching nodes a second time before the call path terminated on the destination switching node; means in the switching node for communicating a redirect message back on the call path to the subset of switching nodes to deny the extension of the call path through the switching node.
Claim 8
Dependent Claim
40 words
The apparatus of claim 5 wherein the means for communicating comprises means for identifying another switching node to which the call path should be extended; and means for inserting the information identifying the other switching node into the redirect message.
Claim 9
Dependent Claim
25 words
The apparatus of claim 6 wherein the means for identifying the other switching node comprises means for searching internal tables stored by the switching node.
Claim 10
Dependent Claim
59 words
The apparatus of claim 7 further comprises means for inserting into the setup message by each of the subset of switching nodes information identifying each of the subset of switching nodes; and means for determining comprises means for searching the information identifying each of the subset of switching nodes to determine the one of the subset of switching nodes.
References Cited (Backward Citations)
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