« PrécédentContinuer »
(12) United States Patent ao) Patent No.: us 6,195,416 Bi
DeCaluwe et al. (45) Date of Patent: *Feb. 27,2001
(54) METHOD TO TRAP A CALLED NUMBER IN A TELECOMMUNICATIONS NETWORK
(75) Inventors: Craig L. DeCaluwe, Naperville;
Robert G. Demmert, St. Charles;
Joseph Kohler, Woodridge; Joseph H.
Mc Carthy, Orland Park, all of IL (US)
(73) Assignee: AT&T Corp., New York, NY (US)
( * ) Notice: This patent issued on a continued prosecution application filed under 37 CFR 1.53(d), and is subject to the twenty year patent term provisions of 35 U.S.C. 154(a)(2).
Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.
(21) Appl. No.: 09/046,046
(22) Filed: Mar. 23, 1998
(51) Int. CI. I HUM 1/24
(52) U.S. CI 379/34; 379/14; 379/16;
(58) Field of Search 379/112, 115,
379/113, 111, 121, 126, 128, 133, 134, 137, 34, 207, 1, 12, 16, 23, 220, 246, 249,
9, 10, 15
METHOD TO TRAP A CALLED NUMBER IN
A TELECOMMUNICATIONS NETWORK
TECHNICAL FIELD OF THE INVENTION
This invention relates to communication networks. In 5 particular, this invention relates to a method for collecting data associated with called numbers and calling numbers.
BACKGROUND OF THE INVENTION
Telecommunication switching networks are well-known. 10 These networks are comprised of large, computer-controlled switching systems routing telephone calls that might carry voice and/or data. Most of these switching systems include a limited ability to trap certain kinds of data for a telephone call. Call traps are software features of switching systems 15 whereby subscribers calling to or from a certain predetermined number, i.e. the trapped number, are identified. Priorart call traps within a single switching system identify all of the subscriber phones that dial a particular number and the incoming trunks on which the calls arrive at the switching 2o system or all of the numbers dialed from a specified number.
In many instances it is desirable to be able to completely document calls through a network, including the time that a call began; when it was answered; when it was terminated; the trunk(s) it was routed on; and which party terminated the 25 call. It is currently only possible to collect all of the foregoing data if the number being called and party calling the particular number are coupled to the same physical switch. In modern telecommunications networks a call might be routed through several switches between a calling party and the party being called. In a large network of 30 numerous switches, a call placed to a telephone that is terminated at another switch cannot be completely documented unless each switch in the path over which the call is routed is programmed to search for and trap the particular called number. Thereafter, reconstructing or documenting 35 the exact route through the network which the call was routed cannot be readily determined simply because of the several different switches a call traverses through a network.
For many reasons, knowing the exact route of a call through a network can be valuable. Knowing the exact route 40 of a call might help diagnose problematic circuitry causing customer complaints or to identify the source of annoying calls. For example, law enforcement agencies needing to pin point an annoyance call origin might be able to do so, regardless of where a call originated from. 45
A method and an apparatus by which calls can be trapped through a network, based upon either the called number or the calling number, would be an improvement over the prior art.
SUMMARY OF THE INVENTION 50
Calls through a switching network can be fully documented if the switches are commonly controlled and operatively coupled together such that the switches are able to respond to externally supplied triggers and to exchange data 5J between them. Trapping a called number or a calling number requires that each switch of a network be programmed or configured to trap a particular number. This is established via an input message into each switch, individually, or by broadcasting the request from a single source. A network management computer is normally connected to each switch 60 and has the capability to send a common message (e.g. a trap message) to all switches. Inasmuch as a call to be trapped might originate from outside the network and might therefore enter a network at virtually any switch thereof, each switch of the network is sent a message to trap a particular 65 call, either on a called number basis, a calling number basis, or some other data.
The switch at which the call originates and every switch that handles the call thereafter, must be capable of, and be programmed to identify and initiate a call trap based on some predetermined criteria. Secondly, when an incoming call to be trapped occurs, the switch at which the call originates begins collecting predetermined data and processes the call as it normally would by routing the call to a subsequent switch in the network. Finally, the originating switch that received the call being trapped, signals the subsequent switch that the call is the subject of a complete data trap and also identifies where the data should be sent. This could be in the form of a destination point code ("DPC") known in the art as a location in a SS7 network. The subsequent switch must be capable of receiving and responding to a call trap instruction and thereafter collect pertinent data on the call being trapped as the originating switch did. Switches routing a trapped call through the switching network each collect data on the call. The data that is collected might include: the trunk on which the call came to a switch; the time of the calls arrival at the switch; the trunk on which the call was routed out of the switch; the identity of the switch the call was routed to and the time at which the call was routed out of a switch; the time when a call was answered and when a call was terminated.
As a call is routed by each switch in the network, it returns collected data back to the switch that routed the call to it. Alternatively, switching systems collecting trap data on a call can send collected data to one or more predetermined switches designated to collect call trap data. Other embodiments would include collecting call trap data at a dedicated, call trap data collection computer or other appropriate processor, which is not necessarily a switching system.
As a call is routed through a network of switches, each switch that passes the call to another switch signals the subsequent switch that the call is to be trapped. Each switch that handles the call identifies the location to send the data, which could be the original switch that received the call. In one embodiment of the invention, data from each switch in the network that handles the call is returned through each switch that previously handled the call such that all of the call data is eventually collected for subsequent processing at the originating switch. The originating switch will continue to receive data from the switches that process the call through the network from the time it is established until the call is terminated. Eventually a complete history of the call for the network is assembled at one location.
The call data that can be collected about the call can include: the originating phone number; the dialed number; the time the call was answered; the identity of the party that terminated call; which trunks routed the call through the network; the time that the call entered the network, i.e. the first off-hook to the network; and the time that the call was terminated, i.e. the first on-hook to the network.
Trapped calls through the network might be identified to network switches by a multi-digit number or other label or tag associated with a call that uniquely identifies a trapped call. A call serial number, label, or tag that identifies trapped calls could be distributed throughout a switching network using the SS7 signaling network, well-known to those skilled in the art. This information could be included in the SS7 call set up message. Trapped calls might also be identified, in part, merely by specifying the trunks over which they are routed and routing such data over the SS7 network as well. This would then be rebuilt at the collection site by linking the trunks together.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a simplified block diagram of a telecommunications network through which a trapped call is to be routed.
DETAILED DESCRIPTION OF THE
FIG. 1 shows a simplified block diagram of a telecommunications switching network 100. A telephone subscriber 102 is coupled to a telephone end office 104. The end office 104 provides so-called local switching to the telephone subscriber 102 in that other subscribers whose phones 106 are coupled to the end office 104 can communicate with each other through switching equipment located within the end office 104. In practice, end office 104 provides telecommu- 10 nications service to subscribers in a geographical region proximate to end office 104. When a telephone subscriber 102 wishes to place a call to another subscriber 108 not coupled to end office 104 but coupled to a different end office 110, the call must be routed through a network of switches. 15
In FIG. 1, several switching systems 112, 114, 116, 118 and 120, are operatively coupled together through a network of communication links or trunks 122, 124, 126, 128, 130, and 132. If a subscriber 102 coupled to end office 104 wishes to place a call to another subscriber 108, who is coupled to 20 a different end office 110, the call is routed through one or more switches that comprise a network of switching systems 112, 114, 116, 118, and 120 simply because no direct connection exists between end office 104 and 110. Those skilled in the art will recognize that the end offices 104 and 25 110 might be only a few miles apart but could also be thousands of miles apart, depending upon how the call is routed.
As set forth above, there may be many reasons it is desirable to track the precise path of a call between a first 3Q subscriber 102 and a second subscriber 108 through the network 100. As one example, subscriber 102 might experience poor transmission quality when calling subscriber 108. Responding to such a complaint by the service provider typically requires the diagnosis of all of the switching hardware and media that might handle calls between the first 35 subscriber 102 and the second subscriber 108. In a large switching network there might be thousands of circuits and trunks over which a call between subscriber 102 and 108 might be routed. Inasmuch as the call between subscriber 102 and 108 might take several different paths through the 40 network 100, for maintenance reasons alone, it is desirable to be able to track the exact path a call takes through network 100. In addition, annoyance calls to or from a subscriber are frequently of concern to law-enforcement and subscribers. Presently, calls routed through a network such as the net- 45 work shown in FIG. 1, cannot readily be traced because of the speed with which the call progresses through the network and because no capability of informing switches that a call is to be traced presently exists.
If the switches 112,114,116,118 and 120 comprising the 50 network 100 are commonly owned and operatively linked together, the switches can be cooperatively programmed to collect data on incoming calls to each switching system and to return collected data to the switching system that previously routed the call. By appropriately programming the switches to trap data on a particular call, the switching systems can all collect pertinent data under program control.
For instance, switching system 112 can be programmed to collect data to a particular number, such as the number of subscriber 108. Alternatively, switching system 112 might be programmed to collect pertinent call data when it detects 60 an incoming call from a particular subscriber, such as subscriber 102. Data that the switches 112,114,116,118 and 120 can collect may include for example: the time when the call was initiated; the identity of the number of the party placing the call; the number being called; the identify of the 65 trunk on which the call came into a switch and the trunk on which a call leaves a switch; the time in which the call was
routed from a switch in the network to another network; the time the call was terminated and the source of the termination request. Those skilled in the art will appreciate that other types of data might also be collected as well.
Each of the switches (104, 110, 112, 114, 116, 118, and
120) are coupled to a signaling network 123 well-known as the SS7 signaling network. The SS7 network is a means by which call information is routed to switches throughout the switching network 100 such that the aforementioned switches receive pertinent call processing information on call routing and set-up and on other call parameters over the SS7 network. The SS7 network can be used to carry call trap information throughout the network 100 by virtue of the fact that all of the switches of the network are linked via SS7 signaling.
Inasmuch as calls to be trapped might not originate within the network but might originate from a foreign switch or network and might therefore enter the network through any switch thereof, the invention taught herein will provide optimum results if each and every switch of the network through which a call will be trapped is programmed with the call trap criteria. A message is broadcast via the SS7 network 123 to each switch of the network to trap calls matching certain criteria. Any switch then receiving a call matching the call trap criteria can be trapped through the network. At present, calls are trapped primarily on the basis of the dialed number or the dialing number.
When a call trap is triggered, the originating switch (112, 114,116,118 or 120) processes the call and sends a message to the next switch via the SS7 network to which the call is routed. The call trap message from the originating switch notifies the subsequent switch that receives the call that the incoming call is to be trapped, i.e. all pertinent call data is to be collected by the switch. As the call is routed from one switch to another, each of the secondary switches that route the call thereafter receive a trap call message from the previous switch included in the SS7 call set-up message and in response thereto, each switch collects pertinent call data. Eventually the call is routed to its destination. Data collected by the switches that handled the call is returned to the originating switch 112, over well-known SS7 signaling links operatively linking the switches together, not shown. Returned data is compiled at the originating switch 112 for subsequent processing.
An alternate embodiment of the invention would include call trap data collection sites that are intermediate switches that routed the call, i.e. not necessarily the originating switch, or the terminating switch. Other call trap data collection sites would collect pertinent data from switches that routed the call. Other alternate embodiments include call trap data collection at other network switches as well, including switches that don't even handle the call being trapped. One or more network switches might be specifically designated by a network operator to collect call trap data from all other network switches, even if such a data collection switch did not process the call.
Another embodiment of the invention would include one or more stand-alone computers or other processors operatively coupled to the switching network that collect call trap data. Still other embodiments would include call trap data collection computers that collect particular types of data pertinent to a call trap. A call trap data collection computer or several such computers distributed throughout a network could be used to assemble data collected from switches that routed a call through a network and output an appropriatelyformatted report.