(12) United States Patent
`(10) Patent N0.:
`US 6,327,258 B1
`
`Deschaine et al.
`(45) Date of Patent:
`Dec. 4, 2001
`
`USOO6327258B1
`
`(54) METHOD AND APPARATUS FOR ROUTING
`INTERNET CALLS
`
`........................ .. 370/260
`5,838,665 * 11/1998 Kahn et al.
`5,848,143 * 12/1998 Andrews et al.
`.
`379/219
`
`5/2000 Farris ................................. .. 370/237
`6,064,653 *
`
`(75)
`
`Inventors: 3:51;: ’1‘)-
`Ronald L. Ward; Kevin W. Hager,
`both of Flower Mound, all of TX (US)
`
`(73) Assignee: Alcatel USA Sourcing, L.P., Plano, TX
`(US)
`
`( * ) Notice:
`
`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 N05 08/777317
`(22)
`Filed:
`Dec 31, 1996
`
`(60)
`
`Related US Application Data
`Provisional application No. 60/014,862, filed on Apr. 4,
`1996.
`
`7
`
`..................................................... H04L 12/66
`Int. Cl.
`(51)
`........................................... .. 370/356, 379/221
`(52) U..S. Cl.
`(58) Fleld of Search ..................................... 370/352, 353,
`370/354> 355a 356a 389a 392a 395a 229>
`235> 236> 400> 401> 402> 403> 404> 405;
`379/89> 90~01> 88~17> 220a 221a 230a 242a
`243
`
`(56)
`
`References Clted
`Us. pATENT DOCUMENTS
`
`......................... .. 379/221
`5,253,288 * 10/1993 Frey et a1.
`
`574187844 :
`5/1995 M9msey et al‘
`““" 379/207
`
`S;:T::e:;:1ét’;i:'
`*
`
`.... “ 379/266
`5:642:411 *
`6/1997 Theis .. ... ..
`
`4/1998 Ronen .................... .. 379/127
`5,745,556 *
`
`8/1998 Sistanizadeh et al
`.... .. 370/401
`5,790,548 *
`9/1998 McMullin .......................... .. 379/215
`5,809,128 *
`100
`
`FOREIGN PATENT DOCUMENTS
`9012466
`10/1990 (W0) ............................ H04L/12/64
`9531060
`11/1995 (W0) .......................... .. H04L/12/66
`
`*
`
`.
`.
`cued by exammer
`Primary Examiner—Wellington Chin
`Assistant Examiner—Kwang B. Yao
`(74) Attorney) Agent) or Firm_Baker Boas LL13.
`
`(57)
`
`ABSTRACT
`
`includes a public
`A telecommunications network (10)
`switched telephone network (12) and an Internet data net-
`work (14). The Internet data network (14) includes an
`Internet routing element (24) and a line access switch (26).
`The Internet routing element (24) is coupled to. end .office
`SWItCheS (16) and local SWItCheS (18) 0f the Pubhc SWItChed
`telephone network (12) by modern trunks (30). The modem
`trunks (30) provide the Internet routing element (24) with
`Internet calls re_routed from the public switched telephone
`network (12) to prevent the Internet calls from congesting
`trunks (22) of the public switched telephone network (12).
`The Internet calls are received at an ATM multiplexer (58)
`within the Internet routing element (24). The ATM multi-
`plexer (58) includes a pool of modems (60) that converts the
`analog signal on the modem trunks (30) into digital data. The
`ATM multiplexer (58) includes an ATM cell adaptation unit
`(66) that converts the digital data into ATM cells for trans-
`mission to an Internet Service Provider (42) over an ATM
`network (48). The ATM multiplexer (58) generates address-
`mg information for the ATM cells through interworkings
`with signaling protocols of Internet calls. The line access
`switch includesa similar ATM multiplexer.(94) to re-route
`Internet calls prior to entering the public sw1tched telephone
`network (12)-
`
`14 Claims, 9 Drawing Sheets
`
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`US. Patent
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`Dec. 4, 2001
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`Sheet 8 0f 9
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`US 6,327,258 B1
`
`58
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`US. Patent
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`Dec. 4, 2001
`
`Sheet 9 0f 9
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`US 6,327,258 B1
`
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`
`
`US 6,327,258 B1
`
`1
`METHOD AND APPARATUS FOR ROUTING
`INTERNET CALLS
`
`RELATED PATENT APPLICATION
`
`This application claims the benefit of US. Provisional
`Application No. 60/014,862, filed on Apr. 4, 1996.
`TECHNICAL FIELD OF THE INVENTION
`
`The present invention relates in general to telecommuni-
`cations signal processing and more particularly to a method
`and apparatus for routing Internet calls.
`BACKGROUND OF THE INVENTION
`As access demand on the Internet or with on-line services
`
`grows, a proportional increase in the stress on telecommu-
`nications equipment occurs to support the access demand.
`Subscribers typically access the Internet
`through one or
`more Internet Service Providers. Each Internet Service Pro-
`
`vider is generally accessed by subscribers using discrete
`local telephone numbers that provide broad coverage into a
`public switched telephone network. Access to the Internet
`Service Provider is typically a free local call where the local
`exchange carrier receives no revenues for the telephone
`usage. Internet Service Providers terminate in end offices of
`the public switched telephone network using conventional
`subscriber numbering plans. No control exists as to Internet
`subscriptions, local telephone number assignments for Inter-
`net Service Providers, or locations of Internet Service Pro-
`viders.
`Internet
`traffic between subscribers and Internet
`
`Service Providers is mainly routed through the existing
`public switched telephone network over the same trunks that
`carry voice, facsimile, and data calls.
`Traditional network engineering traffic guidelines do not
`take into consideration the longer than average hold times of
`Internet calls. Most telecommunications equipment were
`designed based on an average call holding time of three to
`five minutes. However, average call holding times for Inter-
`net calls is significantly longer. Current estimates are that
`Internet and similar services have raised the total average
`call holding time to over ten minutes. This is expected to
`increase as the Internet continues to grow. Current end office
`switches within the public switched telephone network are
`not configured to support extended access to the Internet.
`The increased average call holding times of Internet calls
`place a strain on the public switched telephone network that
`affects the quality of service provided to and expected by the
`local subscriber. The public switched telephone network is
`no longer able to provide effective universal services to its
`customers while meeting the growing Internet demands.
`Increased average call holding times decrease the carrying
`capacity of trunks and, because the calls are typically free,
`decrease toll call revenue per trunk as a result of the
`increased content per call. Though additional trunks may be
`installed to support the increase in call holding times, such
`additions increase trunk group costs and operating expenses.
`Congestion occurs within the public switched telephone
`network as customers attempt and re-attempt their calls.
`Service quality suffers resulting in increased customer dis-
`satisfaction and increased service costs. Expensive and
`complex switch reconfigurations would be needed in order
`to relieve the congestion on the public switched telephone
`network caused by Internet calls. Therefore, it is desirable to
`reduce the congestion in the public switched telephone
`network caused by the long holding times of Internet calls.
`SUMMARY OF THE INVENTION
`
`From the foregoing, it may be appreciated that a need has
`arisen for a technique of avoiding congestion on a public
`
`2
`switched telephone network caused by the long hold times
`of Internet calls. In accordance with the present invention, a
`method and apparatus of routing Internet calls are provided
`that substantially eliminate or reduce disadvantages and
`problems associated with conventional processing of Inter-
`net calls.
`
`According to an embodiment of the present invention,
`there is provided an apparatus for routing Internet calls that
`includes a pool of modems to convert the analog signals of
`Internet calls re-routed from a public switched telephone
`network into a digital data format. An ATM cell adaptation
`unit converts the digital data format into ATM cells. A
`network interface transports the ATM cells to an Internet
`Service Provider over an ATM network separate from the
`public switched telephone network. The ATM cells for the
`Internet calls include addressing information generated by
`an ATM addressing unit in conjunction with the signaling
`protocols of an SS-7 network for determining the appropri-
`ate destination of the Internet calls.
`
`The present invention provides various technical advan-
`tages over conventional Internet call processing. For
`example, one technical advantage is to re-route Internet calls
`off of the public switched telephone network. Another
`technical advantage is to avoid placing Internet calls onto
`the public switched telephone network. Yet another technical
`advantage is to transport Internet calls in asynchronous
`transfer mode cell format over an asynchronous transfer
`mode network to an Internet Service Provider. Other tech-
`
`10
`
`15
`
`20
`
`25
`
`30
`
`nical advantages are readily apparent to one skilled in the art
`from the following figures, descriptions, and claims.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`For a more complete understanding of the present inven-
`tion and the advantages thereof, reference is now made to
`the following description taken in conjunction with the
`accompanying drawings, wherein like reference numerals
`represent like parts, in which:
`FIG. 1 illustrates a block diagram of a telecommunica-
`tions switched network;
`FIG. 2 illustrates a block diagram of an Internet call
`through the telecommunications switched network;
`FIG. 3 illustrates another view of the telecommunications
`switched network;
`FIGS. 4A—C illustrate call control procedures at different
`congestion points within the telecommunications switched
`network;
`FIG. 5 illustrates a block diagram of an Internet routing
`element within the telecommunications network;
`FIG. 6 illustrates a block diagram of an asynchronous
`transfer mode multiplexer of the Internet routing element;
`FIG. 7 illustrates a block diagram of a line access switch
`within the telecommunications network; and
`FIG. 8 illustrates a process flow for processing a call
`through the line access switch.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`FIG. 1 is a block diagram of a telecommunications
`switched network 10. Telecommunications switched net-
`
`work 10 includes a local public switched telephone network
`12 and an Internet data network 14. Public switched tele-
`
`phone network 12 includes a plurality of end offices 16, a
`plurality of local tandem switches 18, and a plurality of
`tandem switches 20. End offices 16, local tandem switches
`
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`US 6,327,258 B1
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`3
`18, and tandem switches 20 are interconnected by a plurality
`of trunks 22 in order to provide adequate means for trans-
`porting telecommunications information from an originating
`subscriber to a destination subscriber in communication with
`end offices 16. Internet data network 14 includes Internet
`routing elements 24 that perform switching functions for
`Internet Calls re-routed from public switched telephone
`network 12. Internet data network 14 may also include line
`access switches 26 coupled to Internet routing elements 24
`and public switched telephone network 12. Asignal transfer
`point network 28 provides control, management, and admin-
`istrative functions for public switched telephone network 12
`and Internet data network 14.
`
`Conventional operation of public switched telephone net-
`work 12 provides for routing of Internet calls through the
`same configuration of trunks 22 used to route voice,
`facsimile, and data calls. In order to avoid installing addi-
`tional trunks 22 to relieve trunk congestion within public
`switched telephone network 12, avoid installing more cross-
`points to relieve concentrator congestion within end offices
`16, and avoid replacing existing equipment within public
`switched telephone network 12, all necessary to handle the
`longer hold times caused by Internet calls, Internet data
`network 14 provides a means to re-route Internet calls and
`eliminate the effect Internet calls have on public switched
`telephone network 12. Internet calls may be re-routed onto
`modem trunks 30 from either local tandem switches 18 or
`
`end offices 16. Internet calls may also be re-routed away
`from public switched telephone network 12 onto modem
`lines 32 by line access switches 26.
`FIG. 2 shows how an Internet call is transferred from a
`local subscriber 40 to an Internet Service Provider 42 within
`
`telecommunications switched network 10 after entering
`public switched telephone network 12. For unloading Inter-
`net calls from trunks 22 within public switched telephone
`network 12 to Internet data network 14, signal transfer point
`network 28 works with local tandem switches 18, end offices
`16, and Internet routing elements 24 to assign modem trunks
`30 and determine the destination for routing the Internet call
`based on signaling protocols of an 88-7 network 44. Con-
`ventional processing and routing is performed within public
`switched telephone network 12 of Non-Internet calls. Public
`switched telephone network 12 may also process and route
`Internet calls in the event of problems occurring within
`Internet data network 14. End office 16 or local switch 18
`
`accepts the Internet call and routes the Internet call to an
`appropriate Internet routing element 24. Internet routing
`element 24 terminates the analog signals received from
`public switched telephone network 12 and adapts the call
`into asynchronous transfer mode cell format. The asynchro-
`nous transfer mode cells are multiplexed for transmission
`across an asynchronous transfer mode network 46 to the
`appropriate Internet Service Provider 42.
`FIG. 3 is another view of a telecommunications switched
`
`network 110 showing potential congestion points due to
`Internet traffic. Telecommunications switched network 110
`
`is shown separated into a public switched telephone network
`112 and Internet data network 114. For conventional
`
`operation, calls originating from a telephone subscriber 139
`or a computer subscriber 140 and destined for an informa-
`tion service provider 142 are routed through public switched
`telephone network 112. Public switched telephone network
`112 includes local access switch 126, originating end office
`switch 116, a tandem switch network 120, and terminating
`end office switch 117, all under the control and supervision
`of a signal
`transfer point 128. Since calls destined for
`information service provider 142 occupy available resources
`
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`of public switched telephone network 112 due to the long
`call holding times, such as for Internet access, congestion
`points occur within public switched telephone network 112.
`Congestion occurs at the subscriber side at originating end
`office switch 116, congestion occurs in the trunk network at
`tandem switch network 120, and congestion occurs at the
`terminating end at terminating end office switch 117. The
`congestion on public switched telephone network 112 will
`exceed engineered switch and network trunking
`arrangements, resulting in call denial. Data subscribers and
`voice subscribers may experience no dialtone, slow dialtone,
`and all trunks busy signals due to the degradation in the
`network quality.
`In order to alleviate the congestion on public switched
`telephone network 112, calls identified as originating from a
`subscriber 139 or 140 and destined for an information
`
`service provider 142 are redirected from public switched
`telephone network 112 onto Internet data network 114.
`Internet data network 114 includes a data switch network
`146 that receives line side redirection of data calls from local
`
`access switch 126 to alleviate the subscriber side congestion
`and originating end office switch 116. Data switch network
`146 also receives trunk side redirection of calls from origi-
`nating end office switch 116 through an Internet routing
`element 124 in order to alleviate trunk network congestion
`at tandem switch network 120. Data switch network 146 also
`receives trunk side redirection of data calls from tandem
`
`switch network 120 in order to alleviate congestion at
`terminating end office switch 117 through an Internet routing
`element 124. Data switch network 146 then appropriately
`routes data calls to information service provider 142. Iden-
`tification and redirection of data calls is performed by signal
`transfer point 128 through an SS7 messaging protocol.
`Internet routing elements 124 are used for grooming and
`transport of data call traffic onto data switch network 146.
`In order to relieve subscriber side congestion at originat-
`ing end office switch 116, a call destined for information
`service provider 142 is identified in order to successfully
`divert
`the data call away from public switch telephone
`network 112. The identification process is performed by
`signal transfer point 128. During a normal call processing
`sequence, line access switch 126 converts the analog POTS
`signal originating from a subscriber 139 or 140 to a digital
`DSO signal and forwards that signal to originating end office
`switch 116 to begin call processing. Call requests that cannot
`be locally connected generate an SS7 message that
`is
`forwarded to signal transfer point 128. The call is completed
`when an SS7 message arrives back from signal transfer point
`128 with instructions on routing. When signal transfer point
`128 determines that the call is being placed to information
`service provider 142 during its digital analysis process on
`the called party address, it initiates a coordinating sequences
`of messages that allows originating end office switch 116 to
`disconnect the call, and free the matrix and free the trunk
`resource between line access switch 126 and originating end
`office switch 116. Signal
`transfer point 128 directs line
`access switch 126 to divert the call from originating end
`office switch 116 trunk resources to another resource, such
`as a dedicated DSO/DS1 circuit or a modem from internal
`pool with an ATM connection, that bypasses public switch
`telephone network 112. Data switch network 146 then cross
`connects the resources between line access switch 126 and
`
`information service provider 142. Line access switch 126
`continues to monitor the subscriber drop throughout the call,
`as would be performed for any call. Upon detecting that the
`subscriber goes on-hook,
`line access switch 126 informs
`originating end office switch 116 so that the subscriber line
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`can be once again made available for incoming and outgoing
`calls. Line access switch 126 also informs signal transfer
`point 128 so that the dedicated DSO/DS1 circuit or ATM
`modem connection can be torn down and made available for
`other calls. If the line disconnect originates at information
`service provider 142, signal
`transfer point 128 notifies
`originating end office switch 116 and line access switch 126
`in order to update their call status. All control information
`exchanges between signal transfer point 128,
`line access
`switch 126, and originating end office switch 116, are
`accomplished using standard signaling messages (such as
`Q.931) over standard interfaces.
`Though line side redirection alleviates congestion directly
`at originating end office switch 116 and indirectly at tandem
`switch network 120 and terminating end office switch 117,
`trunk side redirection is performed to directly eliminate
`trunk network congestion at tandem switch network 120 and
`terminating end office switch 117. Trunk side redirection is
`performed at originating end office switch 116 to adjust
`congestion at tandem switch network 120 and trunk side
`redirection is also performed at tandem switch network 120
`to address congestion at terminating end office 117.
`In order to successfully divert data calls from the trunk
`network of public switched telephone network 112, signal
`transfer point 128 identifies calls originating from subscriber
`16 or 18 and destined for information service provider 142.
`During a normal call processing sequence, originating end
`office switch 116 detects an off-hook condition at subscriber
`
`16 or 18 and generates an SS7 message that is forwarded to
`signal transfer point 128 for call requests that cannot be
`locally connected. The call
`is completed when an SS7
`message is returned from signal transfer point 128 with
`instructions on routing. The call is ended when originating
`end office switch 116 detects the calling end going on-hook
`and thus terminates the call. When signal transfer point 128
`determines that
`the call
`is being placed to information
`service provider 142, it directs originating end office switch
`116 to divert
`the call
`to Internet routing element 124.
`Internet routing element 124 places the call on a resource,
`such as a dedicated DSO/DSI circuit or a modem from an
`internal pool with an ATM connection, that bypasses public
`switched telephone network 112. Data switch network 146
`connects the resource between originating end office switch
`116 and information service provider 142. Originating end
`office switch 116 continues to monitor the subscriber drop
`throughout the call. Once it detects that a subscriber has
`gone on-hook, originating end office switch 116 signals
`signal transfer point 128 through the SS7 network so that the
`call’s connection can be torn down and the resources made
`
`available for other calls. If the disconnect originates at
`information service provider 142, signal transfer point 128
`detects the condition and notifies originating end office
`switch 116 so that it can update its call status.
`Signal transfer point 128 works similarly with tandem
`switch network 120 to redirect data calls from public
`switched network 112 onto Internet data network 114 in
`
`order to alleviate congestion at terminating end office switch
`117 .
`
`Signal transfer point 128 determines where an Internet
`call is to be redirected by maintaining a call detail record of
`calls through telecommunications switched network 110.
`For example, subscribers identified as heavy Internet sub-
`scribers by signal
`transfer point 128 may be line side
`redirected at line access switch 126 so that they are removed
`from public switched telephone network 112 at an earliest
`possible point in order to avoid congestion. Those subscrib-
`ers identified as normal Internet subscribers by signal trans-
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`fer point 128 may be redirected off of public switched
`telephone network 112 at the trunk side of originating end
`office switch 116. Those subscribers identifies as low density
`Internet subscribers by signal
`transfer point 128 may
`traverse through public switched telephone network 112
`with redirection not occurring until somewhere within tan-
`dem switch network 120. In this manner, intelligent rerout-
`ing of data calls can occur to avoid congestion and provide
`smooth call routing within public switched telephone net-
`work 112.
`
`Signal transfer point 128 may attempt to redirect the
`Internet call away from public switched telephone network
`112 at any and all of the redirection points discussed above.
`If a designated route to Internet data network 114 is busy or
`not available, the Internet call overflows for routing back
`through public switched telephone network 112. Once the
`Internet call overflows back to public switched telephone
`network 112, the Internet call may be routed through alter-
`nate paths to Internet data network 114 in higher level
`offices, once again achieving the goal of removing Internet
`traffic from the public switched telephone network 112. The
`Internet call traverses through the entire public switched
`telephone network 112 only as a last resort in the event there
`are no other resources available to redirect the Internet call
`onto Internet data network 114.
`
`FIGS. 4A through 4C show the call control for redirecting
`Internet calls off of public switched telephone network 112.
`FIG. 4A shows the redirection of a line side Internet call at
`
`line access switch 126. An Internet call originates from
`subscriber 140 and proceeds through line access switch 126
`to originating end office switch 116. Originating end office
`switch 116 provides a dial tone for subscriber 140 and
`collects the digits entered by subscriber 140. Originating end
`office switch 116 queries signal transfer point 128 through
`SS7 signaling. Signal transfer point 128 receives the SS7
`message at an SS7 interface 150 and performs a lookup of
`routing instructions within a signal control point 152 in
`conjunction with an administration unit 153. Signal control
`point 152 returns a translated called number to originating
`office switch 116 through SS7 interface 150. Originating end
`office switch 116 routes the call based on the translated
`
`called number response. Originating end office switch 116
`sets up an ISUP call between line access switch 126 and a
`master controller 154 of signal transfer point 128. Master
`controller 154 passes control and routing information for
`information service provider 142 to line access switch 126.
`Line access switch 126 provides an interface to data switch
`network 146 and routes the Internet call through data switch
`network 146 to information service provider 142. Line
`access switch 126 issues a subscriber busy signal to origi-
`nating end office switch 116 to indicate that subscriber 18 is
`off hook.
`FIG. 4B shows redirection of a trunk side Internet call at
`
`originating end office switch 116. An Internet call originates
`from subscriber 140 to originating end office switch 116.
`Originating end office switch 116 provides dial tone and
`collects digits entered by subscriber 140. In response to the
`digits collected, originating end office switch 116 queries
`signal transfer point 128 through an SS7 messaging proto-
`col. Signal transfer point 128 receives the SS7 message at
`SS7 interface 150 and obtains routing instructions from
`signal control point 152 in conjunction with administration
`unit 153. Signal control point 152 returns a translated called
`number to originating end office switch 116 through SS7
`interface 150. Originating end office switch 116 sets up the
`route for the Internet call based on this response. Originating
`end office switch 116 sets up an ISUP call between master
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`controller 154 of signal transfer point 128 and an Internet
`routing element 144. Master controller 154 passes control
`information to Internet routing element 154. Internet routing
`element 154 establishes the connection for the Internet call
`onto data switch network 146 and provides the interface
`with data switch network 146.
`FIG. 4C shows redirection of a trunk side Internet call at
`tandem switch network 120. Subscriber 140 originates an
`Internet call through originating end office switch 116 and to
`tandem switch network 120. Tandem switch network 120
`
`queries signal transfer point 128 through the SS7 messaging
`protocol. The SS7 message received at SS7 interface 150
`and routing instructions are obtained from signal control
`point 152. Signal control point 152 returns a translated
`called number to tandem switch network 120 through SS7
`interface 150. Tandem switch network 120 sets up an ISUP
`call between its associated Internet routing element 144 and
`master controller 154 of signal transfer point 128. Master
`controller 154 obtains routing information for information
`service provider 142 from signal control point 152,
`in
`conjunction with administration unit 153, and passes control
`and connection information to Internet routing element 144.
`Internet routing element 144 establishes the connection and
`provides the interface with data switch network 146. The
`Internet call is then appropriately redirected through data
`switch network 146 to information service provider 142.
`FIG. 5 is a block diagram of an Internet routing element
`24. Internet routing element 24 includes an administration
`subsystem 50, a matrix fabric subsystem 52, network ter-
`minators 54, and a resource subsystem 56. Administration
`subsystem 50 provides control, maintenance, test access,
`and timing functions for Internet routing element 24. Net-
`work terminators 54 provide the signal interfaces to and
`from telecommunications switched network 10. Matrix fab-
`
`ric subsystem 52 provides the switching and cross-connect
`functions for Internet routing element 24. Resource sub-
`system 56 provides subrate data multiplexing, multi-point
`junction, digital matrix bridge, and ATM multiplexing func-
`tions. Routing and transportation of Internet calls is per-
`formed through ATM multiplexer 58.
`FIG. 6 is a block diagram of ATM multiplexer 58. ATM
`multiplexer 58 includes a pool of modems 60, a control
`processor 62, an ATM addressing unit 64, an ATM cell
`adaptation unit 66, a backplane interface 67, and a network
`interface 68. In operation, an Internet call is routed to ATM
`multiplexer 58 over a backplane 70 of Internet routing
`element 24. The Internet call is processed by the appropri-
`ately assigned modem 60 in order to convert from analog
`format into digital format. The digital data generated by
`modem 60 is converted into ATM cells by ATM cell adap-
`tation unit 66. Addressing information is placed into the
`ATM cells by ATM addressing unit 64 in response to the
`determination of the destination by control processor 62.
`Control processor 62 communicates with signal
`transfer
`point network 28 to obtain the destination information from
`the signaling protocols of SS-7 network 44. Once the ATM
`cells have been generated and contain the appropriate
`addressing information, the ATM cells are transported to and
`from ATM network 46 by network interface 68 or by
`backplane interface 67 through network terminators 54.
`FIG. 7 is a block diagram of a line access switch 26 to
`re-route Internet calls prior to entering public switched
`telephone network 12. Line access switch 26 includes a
`digital loop carrier central terminal 80 and a digital loop
`carrier remote terminal 82. Remote terminal 82 includes a
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