`Alexander et al.
`
`(10) Patent N0.:
`(45) Date 0f Patent:
`
`US 6,798,767 B1
`Sep. 28, 2004
`
`US006798767B1
`
`(54) SYSTEM AND METHOD FOR GENERATING
`MULTIPLE LINE APPEARANCES IN A
`COMMUNICATION NETWORK
`
`_
`
`(75) Inventors, John D_ Alexander, Plano, TX (Us);
`.
`_
`Kenneth P. Pruskl, Plano, TX (US),
`Michael H. Mcclung, Alexandria, VA
`(Us)
`_
`_
`(73) Asslgneer C1860 Technology, 1116-, San Jose, CA
`(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. No.: 09/442,161
`(22) Filed:
`Nov. 16, 1999
`
`(51) Int. Cl.7 .............................................. .. H04L 12/66
`(52) US. Cl. .................. .. 370/352; 370/401; 379/9301;
`379/211.02; 379/221.01; 455/445
`(58) Field of Search ............................... .. 370/352, 353,
`370/354, 355, 356, 389, 400, 401, 522;
`379/8817, 93.01, 207.02, 207.03, 207.04,
`207.08, 207.09, 211.01, 211.03, 211.04,
`212.01, 220.01, 221.01, 221.02, 221.08,
`221.09; 455/445, 461
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`4,876,707 A 10/1989 Hashimoto
`5,742,905 A
`4/1998 Pepe et a1. ................ .. 455/461
`5,809,128 A * 9/1998 McMullin ............ .. 379/215.01
`5,862,207 A
`1/1999 Aoshima
`5,963,864 A * 10/1999 O’Neil et al. ............. .. 455/445
`6,282,275 B1 * 8/2001 Gurbani et a1. ...... .. 379/14206
`6,304,565 B1 * 10/2001 Ramamurthy ............. .. 370/352
`
`,
`
`,
`
`6,327,267 B1 * 12/2001 Valentine et a1. ......... .. 370/466
`6,327,358 B1 * 12/2001 March et a1. ........ .. 379/221.01
`6,359,892 B1
`3/2002 $11991
`6,421,339 B1
`7/2002 Thomas
`6,421,437 B1 * 7/2002 Slutsman ............. .. 379/201.02
`6,445,682 B1
`9/2002 WeitZ
`6 445 694 B1
`9
`6 449 269 B1
`9 0002 Edholm
`6,453,034 B1 * 9/2002 Donovan et a1. .... .. 379/220.01
`6,480,484 B2 * 11/2002 Morton ..................... .. 370/352
`6,515,997 B1 * 2/2003 Feltner et a1. ............ .. 370/401
`6,519,252 B2
`2/2003 Salberg
`6,526,033 B1
`2/2003 Wang et a1.
`6,532,286 B1
`3/2003 Burg
`
`/2002 SwartZ
`
`OTHER PUBLICATIONS
`
`Cisco Systems, Inc.; “System Description for the Cisco
`Communications Network Version 2.1;” Cisco Communi
`cations Network; all, 1997.
`
`* cited by examiner
`
`Primary Examiner—Bob A. Phunkijlh
`(74) Attorney, Agent, or Firm—Baker Botts L.L.P.
`(57)
`ABSTRACT
`
`A communication system includes a communication
`network, and an originating telephony device, a target tele
`phony device, and a call manager coupled to the commu
`nication network. The call manager signals the target tele
`phony device to indicate an incoming call from the
`originating telephony device. The call manager includes an
`alternate number list that identi?es at least one alternate
`telephony device to be signaled in response to an incoming
`call directed to the target telephony device. The call manager
`additionally includes one or more mapping tables associat
`ing a network address with each identi?ed alternate tele
`phony device.
`
`34 Claims, 5 Drawing Sheets
`
`|
`|
`
`MOBILE TELEPHONE
`SWITCHING OFFICE
`
`CISCO SYSTEMS, INC. Ex. 1006 Page 1
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`U.S. Patent
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`Sep. 28, 2004
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`Sheet 1 of 5
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`US 6,798,767 B1
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`
`
`
`
`IIonEr--memmmnmmnnnnnn:m@wmmwmwLo2§c8?9
`
`/K63
`
`mzo_._&§Baez
`
`BEOoz__.§_;m
`
`fieE
`
`44<o
`
`
`
`mmo<z<2new
`
`clsco SYSTEMS, Inc. Ex. 1006 Page 2
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`CISCO SYSTEMS, INC. Ex. 1006 Page 2
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`U.S. Patent
`
`Sep. 28, 2004
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`Sheet 2 0f 5
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`US 6,798,767 B1
`
`FIG. 2
`CALL MANAGER
`
`>
`
`108\ CONTROL
`SOFTWARE
`
`ADDRESS
`MAPPING TABLE
`
`110/
`
`ALTERNATE
`NUMBER LIST
`
`I06
`
`FIG. 3
`ALTERNATE NUMBER RING DELAY TIME
`
`I002
`
`2150
`
`112<
`
`214-555-5001
`
`3015
`
`214-555-5003
`
`\ILNLAOO
`
`sI14
`
`CISCO SYSTEMS, INC. Ex. 1006 Page 3
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`U.S. Patent
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`Sep. 28, 2004
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`Sheet 3 0f 5
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`US 6,798,767 B1
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`1200
`FIG. 4A /
`
`PHONE NUMBER
`
`DEVICE/GROUP NAME \
`
`1001
`
`1002
`
`1002
`
`PHONE1
`
`PHONE2
`
`PHONE3
`
`2000-2999
`
`PBXGATEWAY
`
`214-555-5001
`
`CATEWAYGROUP1
`
`214-555-5002
`
`GATEWAYGROUP1
`
`> 123
`
`122*
`
`214-555-5003
`
`GATEWAYGROUP1
`
`972-555—6000
`3015
`703-XXX-XXXX
`
`GATEWAY5
`F’lfl0NE25
`GATEWAYGROUPZ
`
`120b
`FIG. 4B /
`DEVICE NAME
`1P ADDRESS
`
`PHONE1
`
`PHONE2
`
`PBXGATEWAY
`
`CATEWAY1
`
`GATEWAYZ
`GATEWAY3
`
`GATEWAY5
`
`PHONE25
`
`GATEWAY10
`
`150.100.30.1
`
`150.100.30.2
`
`150.100.30.50
`
`150.100.30.55
`
`1 50.1 00.30.56
`150.100.30.57
`
`1 50.1 00.30.58
`
`150.200.70.15
`
`150.200.70.50
`
`GATEWAY1 1
`
`' 150.200.70.51
`
`>124
`
`CISCO SYSTEMS, INC. Ex. 1006 Page 4
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`U.S. Patent
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`Sep. 28, 2004
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`Sheet 4 0f 5
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`US 6,798,767 B1
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`/2OO
`
`/202
`
`I
`CALL MANAGER QUERIES
`ALTERNATE NUMBER LIST
`I
`CALL MANAGER RETRIEVES
`IP ADDRESSES OF DEVICES
`OR GATEWAYS ASSOCIATED
`WITH ALTERNATE NUMBERS
`
`FIG. 5A
`
`I
`CALL MANAGER RETRIEVES
`IP ADDRESS OF DEVICE
`ASSOCIATED WITH CALLED
`NUMBER FROM MAPPING TABLE
`I
`CALL MANAGER DIRECTS
`CALL TO IP ADDRESS OF
`CALLED TELEPHONY DEVICE
`I
`CALL MANAGER SIGNALS
`DEVICE TO RING
`
`CALL INITIATED TO
`IP TELEPHONY DEVICE
`I
`CALL MANAGER RECEIVES
`REQUEST TO CONNECT CALL
`TO DEVICE ASSOCIATED
`WITH CALLED NUMBER
`I
`
`2ID\
`
`212\
`
`/204
`
`/206
`
`/208
`
`I
`CALL MANAGER WAITS
`FOR SPECIFIED PERIOD
`
`CALL MANAGER
`DIRECTS CALL TO
`IP ADDRESS OF
`CALLED DEVICE
`I
`CALL MANAGER
`SIGNALS DEVICE
`TO RING
`
`CALL MANAGER SENDS
`MESSAGE TO THE APPROPRIATE
`224 /
`GATEWAY INDICATING
`DEVICE TO BE CALLED
`I
`GATEWAY UNPACKS MESSAGE
`TO DETERMINE NUMBER OF
`226 /
`DEVICE TO BE CALLED
`I
`GATEWAY SENDS SIGNALING
`INFORMATION TO CONNECT
`228 /
`CALL TO ALTERNATIVE DEVICE
`I
`230 / CALLED DEVICE RINGS
`
`(I)
`
`CISCO SYSTEMS, INC. Ex. 1006 Page 5
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`U.S. Patent
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`Sep. 28,2004
`
`Sheet 5 0f 5
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`US 6,798,767 B1
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`FIG. 5B
`
`I
`PROCESS OFF-HOOK
`PROCESSING INFORMATION
`
`/238
`
`232
`
`CALL
`MANAGER
`RECEIVES OFF-HOOK
`SIGNAL FROM A
`DEVICE?
`
`234
`
`ANY OFF
`HOOK PROCESSING
`INFORMATION ASSOCIATED
`WITH OFF-HOOK
`DEVICE?
`
`236/
`
`SIGNAL OTHER DEVICES
`TO STOP RINGING
`
`I
`CONNECT CALL TO
`OFF-HOOK DEVICE
`
`240/
`
`I
`RELEASE OTHER DEVICES
`242/ OR PLACE ON KEY HOLD
`
`r
`
`(END)
`
`CISCO SYSTEMS, INC. Ex. 1006 Page 6
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`US 6,798,767 B1
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`1
`SYSTEM AND METHOD FOR GENERATING
`MULTIPLE LINE APPEARANCES IN A
`COMMUNICATION NETWORK
`
`TECHNICAL FIELD OF THE INVENTION
`
`This invention relates generally to the ?eld of
`telecommunications, and more speci?cally to a system and
`method for generating multiple line appearances in a com
`munication netWork.
`
`10
`
`BACKGROUND OF THE INVENTION
`
`15
`
`Historically, telecommunications have involved the trans
`mission of voice and fax signals over a netWork dedicated to
`telecommunications, such as the Public SWitched Telephone
`NetWork (PSTN) or a Private Branch Exchange (PBX).
`Similarly, data communications betWeen computers have
`also historically been transmitted on a dedicated data
`netWork, such as a local area netWork (LAN) or a Wide area
`netWork
`Currently, telecommunications and data
`transmissions are being merged into an integrated commu
`nication netWork using technologies such as Voice over
`Internet Protocol (VoIP). Since many LANs and WANs
`transmit computer data using Internet Protocol (IP), VoIP
`25
`uses existing LAN technology to transport voice and fax
`signals by converting these signals into digital data and
`encapsulating the data for transmission over an IP netWork.
`Because of the integration of IP telephony devices and data
`netWorks, many features are noW available to users of VoIP
`(and other voice/data integration technologies) that have not
`been available to users of traditional telecommunication
`netWorks.
`
`SUMMARY OF THE INVENTION
`
`35
`
`In accordance With the present invention, a system and
`method for generating multiple line appearances in a com
`munication netWork is provided that substantially eliminates
`or reduces disadvantages or problems associated With pre
`viously developed systems and methods. In particular, the
`present invention contemplates a system and method for
`generating line appearances at one or more alternate tele
`phony devices associated With a target telephony device in
`response to a call made to the target telephony device.
`In one embodiment of the present invention, a commu
`nication system is provided that includes a communication
`netWork, and an originating telephony device, a target tele
`phony device, and a call manager coupled to the commu
`nication netWork. The call manager signals the target tele
`phony device to indicate an incoming call from the
`originating telephony device. The call manager includes an
`alternate number list that identi?es at least one alternate
`telephony device to be signaled in response to an incoming
`call directed to the target telephony device. The call manager
`additionally includes one or more mapping tables associat
`ing a netWork address With each identi?ed alternate tele
`phony device.
`In another embodiment of the present invention, a method
`of generating multiple line appearances in a communication
`netWork is provided. The method includes receiving a call
`initiation request from an originating telephony device that
`is coupled to the communication netWork. The call initiation
`request is directed to a target telephony device that is also
`coupled to the communication netWork. The method also
`includes determining a telephone number of at least one
`alternate telephony device from an alternate number list
`
`40
`
`45
`
`55
`
`65
`
`2
`associated With the target telephony device, and determining
`a netWork address associated With the alternate telephony
`device. The method further includes signaling the target
`telephony device to indicate the call initiation request from
`the originating telephony device, and signaling the alternate
`telephony device using the determined netWork address to
`indicate the call initiation request from the originating
`telephony device.
`Technical advantages of the present invention include a
`system and method that alloW multiple telephony devices to
`be rung in response to a call being made to a single
`telephony device. For example, a user may associate one or
`more alternate devices With a target telephony device such
`that the alternate devices are rung When a call is placed to the
`target telephony device. Alternate devices that may be rung
`include IP telephony devices and non-IP telephony devices,
`such as PSTN and PBX devices. The alternate devices may
`be rung simultaneously With the target device, or one or
`more of the alternate devices may be rung at a speci?ed time
`after the target telephony device is rung. Afurther advantage
`of the present invention includes the ability to remotely
`create and edit a list of alternate telephony devices associ
`ated With a telephony device.
`Other technical advantages are readily apparent to one
`skilled in the art from the folloWing ?gures, descriptions,
`and claims.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`For a more complete understanding of the present
`invention, and for further features and advantages, reference
`is noW made to the folloWing description, taken in conjunc
`tion With the accompanying draWings, in Which:
`FIG. 1 illustrates an exemplary communication netWork
`in accordance With the present invention;
`FIG. 2 illustrates an exemplary call manager in accor
`dance With the present invention;
`FIG. 3 illustrates an exemplary alternate number list in
`accordance With the present invention;
`FIG. 4A illustrates an exemplary mapping table in accor
`dance With the present invention;
`FIG. 4B illustrates another exemplary mapping table in
`accordance With the present invention;
`FIG. 5A illustrates a ?rst portion of an exemplary method
`of generating multiple line appearance in the communication
`netWork in accordance With the present invention; and
`FIG. 5B illustrates a second portion of an exemplary
`method of generating multiple line appearance in the com
`munication netWork in accordance With the present inven
`tion.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`FIG. 1 illustrates an exemplary communication netWork
`10. Although a speci?c communication netWork is illus
`trated in FIG. 1, the term “communication network” should
`be interpreted as generically de?ning any netWork capable
`of transmitting telecommunication signals, data, and/or mes
`sages. In the illustrated embodiment, communication net
`Work 10 includes a plurality of local area netWorks (LANs)
`20 interconnected using a Wide area netWork
`30.
`Each LAN 20 is a computer data netWork that is further
`operable to transmit audio and/or video telecommunication
`signals. In the particular embodiment illustrated in FIG. 1,
`LANs 20 are Internet Protocol (IP) netWorks. HoWever,
`LANs 20 may be any type of netWork that alloWs the
`
`CISCO SYSTEMS, INC. Ex. 1006 Page 7
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`US 6,798,767 B1
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`25
`
`3
`transmission of audio and video telecommunications, as
`Well as traditional data communications. Therefore,
`although subsequent description Will primarily focus on IP
`telephony devices, it should be understood that other appro
`priate telephony devices, such as Voice over Frame Relay
`devices, are also included Within the scope of this descrip
`tion.
`LANs 20 may be directly coupled to other IP netWorks
`including, but not limited to, WAN 30 and any IP netWorks
`coupled to WAN 30 (such as other LANs 20 or the Internet
`40). Since all IP networks share a common method of
`transmitting data, telecommunication signals may be trans
`mitted betWeen telephony devices located on different, but
`interconnected, IP networks. In addition to being coupled to
`other IP netWorks, LANs 20 may also be coupled to non-IP
`telecommunication netWorks through the use of gateWays.
`For eXample, LAN 20a is coupled to a private branch
`exchange (PBX) 50 through a gateWay 52. PBX 50 repre
`sents analog and/or digital telephone systems used by busi
`nesses. PBX 50 includes a plurality of extension telephony
`devices or subscriber sets 54, 55 to Which PBX 50 directs
`incoming telephone calls. GateWay 52 may be either an
`analog or digital gateWay depending on the type of PBX 50
`to Which it is coupled. The operation of the gateWays in
`communication netWork 10 is described in greater detail
`beloW.
`Another non-IP netWork to Which LANs 20 may be
`coupled is the Public SWitched Telephone NetWork (PSTN)
`60. PSTN 60 includes sWitching stations, central of?ces,
`mobile telephone sWitching of?ces, pager sWitching of?ces,
`remote terminals, and other related telecommunications
`equipment that are located across the country. For eXample,
`central of?ces (COs) 62 connect telephone customers, such
`as residences and businesses, to PSTN 60. In the illustrated
`embodiment, LAN s 20 are coupled to selected central offices
`62 through the use of gateWays 64, described beloW. Central
`offices 62 in a particular area, such as COs 62a and 62b in
`Dallas, may be directly connected to alloW local communi
`cation betWeen residences and businesses in that area.
`Central offices 62 are also coupled through a long distance
`netWork 66 that alloWs communication betWeen residences
`and business coupled to central offices in different areas,
`such as CO 62a in Dallas and CO 62c in San Jose. The entity
`that oWns the communication lines comprising long distance
`netWork 66 (there are typically several different entities,
`each having their oWn communication lines) charges a fee
`for the use of these lines. HoWever, one advantage of IP
`telephony is that a company oWning (or leasing) LANs 20
`and WAN 30 may avoid such fees for calls betWeen LAN
`20a and LAN 20b by using WAN 30 to transmit calls
`betWeen the LANs. Internet 40 may also be used to transmit
`calls, but the quality of such calls is typically loW.
`IP netWorks transmit data (including voice and video data)
`by placing the data in packets and sending each packet
`individually to the selected destination. This is knoWn as a
`packet-sWitched netWork. Unlike a circuit-sWitched netWork
`(like PSTN 60), dedicated bandWidth is not required for the
`duration of a call or faX transmission over LANs 20, WAN
`30 or Internet 40. Instead, each telephony device sends
`packets across the netWork as they become available for
`transmission. This feature makes bandWidth available for
`other data When voice or faX data is not being transmitted.
`The technology that alloWs telecommunications to be
`transmitted over an IP netWork is typically referred to as
`Voice over IP (VoIP). IP telephony devices 22—24 are
`coupled to LAN 20a to alloW such communication over
`
`40
`
`45
`
`55
`
`65
`
`4
`LAN 20a. IP telephony devices 22—24 have the capability of
`encapsulating a user’s voice (or other inputs) into IP packets
`so that the voice can be transmitted over LAN 20a, WAN 30
`and/or Internet 40. IP telephony devices may include
`telephones, faX machines, computers running telephony
`softWare (such as MICROSOFT NETMEETING), or any
`other device capable of performing telephony functions over
`an IP netWork.
`One eXample of an IP telephony device is an IP Ethernet
`telephony device that plugs directly into an Ethernet R145
`jack, as opposed to a traditional R111 telephone jack.
`Alternatively, a user may plug a handset or headset directly
`into a personal computer 24 on LAN 20 to form a virtual IP
`telephony device. An IP telephony device typically
`resembles a traditional digital PBX telephony device, but
`instead of connecting to a proprietary PBX port, the tele
`phony device plugs into a LAN jack, such as an Ethernet
`jack. An IP telephony device operates as a standard IP
`netWork device and typically has its oWn IP address
`(although it may be assigned dynamically). IP telephony
`devices may also have the ability to handle data coding and
`decoding at the telephony device. This feature alloWs the
`telephony device to sWitch compression schemes on
`demand, such as sWitching betWeen G711 and G723 com
`pression.
`A call manager 26a controls IP telephony devices 22—24
`(a similar call manager 26b may be located on LAN 20b).
`Call manager 26a is an application that controls call
`processing, routing, telephone features and options (such as
`call hold, call transfer and caller ID), device con?guration,
`and other telephony functions and parameters Within com
`munication netWork 10. Call manager 26a can control all of
`the IP telephony devices on LAN 20a, and it may also
`control IP telephony devices located across WAN 30. For
`eXample, call manager 26a is capable of controlling tele
`phony devices on LAN 20b. Thus, call manager 26b may be
`eliminated entirely or used as a redundant controller.
`When a user Wishes to place a call from one IP telephony
`device on LAN 20a to another IP telephony device on LAN
`20a (an intra-LAN call), the calling telephony device trans
`mits a signal to call manager 26a indicating the desired
`function and the telephony device to be called. Call manager
`26 then checks on the availability of the called telephony
`device and, if available, sets up the call by instructing the
`calling party (the originating telephony device) to set up an
`audio stream With the called (target) telephony device. The
`initial signaling betWeen call manager 26a and either the
`originating telephony device or the target telephony device
`is transmitted over LAN 20a (and, if necessary, WAN 30)
`using Transmission Control Protocol (TCP) or any other
`suitable protocol. A TCP layer in the transmitting telephony
`device divides the data to be transmitted into one or more
`packets, numbers the packets, and then forWards them
`individually to the IP netWork layer for transmission to the
`destination telephony device. Although each packet has the
`same destination IP address, the packets may travel along
`different paths to reach the intended destination. As the
`packets reach the destination telephony device, the TCP
`layer reassembles the individual packets and ensures that
`they all have arrived. Once TCP reassembles the data, it
`forWards the data to the destination telephony device as a
`single message.
`After call manager 26a has initiated the call, a codec
`(coder/decoder) converts the voice, video or faX signals
`generated by the users of the telephony devices from analog
`voice signals into digital form. The codec may be imple
`mented either in softWare or as special-purpose hardWare in
`
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`5
`IP telephony devices 22—24. In the case of an IP telephony
`device, as the user speaks into the handset, the codec
`converts the analog voice signals into digital data. The
`digitally encoded data is then encapsulated into IP packets so
`that it can be transmitted over LAN 20a.
`The encapsulation is typically performed by Real-Time
`Transport Protocol (RTP) running over UDP (User Data
`gram Protocol), although other appropriate protocols may be
`used. As With TCP, UDP uses the Internet Protocol to get
`data packets from one computer to another. Unlike TCP,
`hoWever, UDP does not provide sequencing and error
`checking of the arriving packets. HoWever, since UDP does
`not perform these functions, UDP operates faster than TCP
`and is useful When loW delay times are more important than
`accuracy. This is true of audio and video streaming since it
`is critical that the data be transmitted as quickly as possible,
`but it is not critical that every single packet is reassembled
`correctly (either its absence is negligible or it contents can
`be extrapolated by the destination telephony device). Once
`UDP has received and reassembled the IP packets at the
`destination telephony device, a codec in the destination
`telephony device translates the digital data into analog voice
`signals for presentation to the user. The entire process is
`repeated each time any call participant (or any other source)
`generates an audio, video, or faX signal.
`In addition to intra-LAN telephone calls, calls can also be
`placed to and received from non-IP telephony devices 54,
`55, 67, 68, 69, 70, 71 that are connected to PSTN 60 or PBX
`50. Such calls are made through a gateWay 52, 64. Because
`gateWay 52 performs similarly to gateWay 64, only gateWay
`64 Will be discussed in further detail. GateWay 64 converts
`analog or digital circuit-switched data transmitted by PSTN
`60 to packetiZed data transmitted by LAN 20, and vice
`versa. When voice data packets are transmitted from LAN
`20, gateWay 64 retrieves the data contained in the incoming
`35
`packets and converts this digital data to the analog or digital
`format used by the PSTN trunk to Which gateWay 64 is
`coupled. Since the digital format for voice transmissions
`over an IP netWork is often different than the format used on
`the digital trunks of PSTN 60, the gateWay provides con
`version betWeen these different digital formats, referred to as
`transcoding. GateWay 64 also translates betWeen the VoIP
`call control system and the Signaling System 7 (SS7)
`protocols used in PSTN 60, including, but not limited to,
`Integrated Services Digital NetWork (ISDN) protocols.
`For voice transmissions from PSTN 60 to LAN 20, the
`process is reversed. GateWay 64 takes the incoming voice
`transmission (either in analog or digital form) and converts
`it into the digital format used by LAN 20. The digital data
`is then encapsulated into IP packets and transmitted over
`LAN 20.
`When making a call to a PSTN telephony device 67—71
`from IP telephony device 22 on LAN 20a, the voice or faX
`signal generated by the user of IP telephony device 22 is
`digitiZed and encapsulated, as described above. The packets
`are then transmitted over LAN 20a to gateWay 64. If more
`than one PSTN gateWay 64 is coupled to LAN 20, call
`manager 26 determines Which gateWay is to receive the
`transmission based on the telephone number (e.g., the North
`American Numbering Plan (NANP) number) of the PSTN
`telephony device. GateWay 64 retrieves the IP packets and
`converts the data to the format (either digital or analog) used
`by the PSTN trunk to Which the gateWay is connected. The
`voice signals are then sent to the PSTN telephony device
`67—71 over PSTN 60. This process, and the reverse process,
`is continued betWeen PSTN 60 and LAN 20 through gate
`Way 64 until the call is complete.
`
`55
`
`65
`
`6
`Calls can also be made betWeen an IP telephony device
`located on LAN 20 and another IP telephony device located
`on another LAN 20, across WAN 30, or on Internet 40. For
`eXample, a call may be place betWeen IP telephony device
`22 connected to LAN 20a and IP telephony device 25
`connected to LAN 20b. As discussed above, the analog
`voice or faX data is digitiZed and encapsulated into IP
`packets at the originating IP telephony device 22. HoWever,
`unlike communications With telephony devices on PSTN 60,
`gateWay 64 is not needed to convert the IP packets to another
`format. Instead, a router (or other similar device) directs the
`packets to the IP address of the target IP telephony device
`25. IP telephony device 25 then retrieves the data and
`coverts it to analog form for presentation to the user. IP
`telephony device 25 may be controlled by the same call
`manager 26a as IP telephony device 22, or it may be
`controlled by call manager 26b on LAN 20b.
`When a call is placed to an IP telephony device, for
`eXample IP telephony device 22, a call initiation request is
`?rst sent to call manager 26a. If the originating telephony
`device is an IP telephony device (e.g., an intra-LAN or
`inter-LAN IP call), the originating IP telephony device
`generates the call initiation request and sends the request to
`call manager 26a. If the originating telephony device is a
`non-IP telephony device, such as PSTN telephony device 68,
`gateWay 64a ?rst intercepts the incoming call from CO 62a,
`and sends a call initiation request to call manager 26a
`indicating the IP telephony device that is being called. In
`either case, once call manager 26a receives the call initiation
`request, call manager 26a sends a signal to the target IP
`telephony device offering the call to the telephony device.
`If the target telephony device (IP telephony device 22) can
`accept the call (e. g., it is not in use or under a Do Not Disturb
`instruction from the user), IP telephony device 22 replies to
`call manager 26a that it Will accept the call. Upon receiving
`this acceptance, call manager 26a transmits a signal to IP
`telephony device 22 to cause it to ring. The telephony
`device’s user can then hear the ring and can take the
`telephony device “off-hook” to receive the call. Taking the
`telephony device off-hook may include, but is not limited to,
`picking up a handset, pressing the ringing line’s button,
`pressing a speakerphone button, or otherWise indicating that
`the telephony device is ready to receive the incoming call.
`For the purposes of this application, the term “off-hook” is
`used to generically indicate a condition of a telephony
`device When it is ready to initiate or receive telecommuni
`cation signals. Once IP telephony device 22 has been taken
`off-hook, call manager 26a sets up an RTP audio and/or
`video stream betWeen IP telephony device 22 and the
`originating telephony device. If the originating telephony
`device is a non-IP telephony device, such as PSTN tele
`phony device 68, the data streaming occurs betWeen IP
`telephony device 22 and gateWay 64a. GateWay 64a then
`transmits the audio and/or video data to PSTN telephony
`device 68.
`FIG. 2 illustrates an exemplary call manager 26. Call
`manager 26 includes a netWork interface 102 that receives
`data from and transmits data to LAN 20 (or any other type
`of netWork to Which call manager 26 is coupled). NetWork
`interface 102 may be any electrical, physical,
`electromagnetic, or Wireless connection enabling call man
`ager 26 to be coupled to a netWork. One eXample of netWork
`interface 102 is an RJ-45 interface, Which is typically used
`in an Ethernet netWork. Call manager 26 also includes a
`processor 104 and a memory 106 that is accessible by
`processor 104. Memory 106 may include any type of volatile
`or non-volatile computer memory such RAM (or its
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`CISCO SYSTEMS, INC. Ex. 1006 Page 9
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`US 6,798,767 B1
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`7
`variants), Flash, ROM, PROM, EPROM, EEPROM, or any
`other appropriate means of storing data. Memory 106 may
`also include media storage devices including, but not limited
`to, hard drives, diskettes, CD-ROMs, DVD-ROMs, or other
`optical or magnetic storage devices.
`Memory 106 contains telephony control softWare or ?rm
`Ware 108 that provides the various telephony functions
`needed to control IP telephony devices. Examples of these
`functions include, but are not limited to, netWork
`interfacing, IP tasks (e.g., a TCP/IP stack), telephony device
`set-up and con?guration, call set-up, and Web-based admin
`istration and help services. It should be noted that although
`the term “call manager” has been used to refer to a complete
`computer system running telephony control softWare, the
`term may also refer only to the control softWare. Adedicated
`computer is not needed to run the call manager control
`softWare. For example, the softWare may be loaded on an
`existing computer, such as a server, on the IP netWork.
`Alternatively, the call manager function may be distributed
`throughout each LAN 20 on the various IP telephony
`devices. The call manager softWare may be embodied in any
`type of computer-readable medium including, but not lim
`ited to, hard drives, diskettes, CD-ROMs, DVD-ROMs, or
`other optical or magnetic storage devices.
`Memory 106 also contains at least one alternate number
`list 110 and one or more address mapping tables 120. Using
`control softWare 108, processor 104 is operable to access
`list(s) 110 and tables 120 in order to set up calls betWeen
`telephony devices and to create multiple line appearances
`(e.g., ring multiple telephony devices) When a call is placed
`to an IP telephony device.
`FIG. 3 illustrates an exemplary alternate number list 110.
`Potentially, every IP telephony device controlled by call
`manager 26 can have an associated alternate number list.
`List 110 is an example of an alternate number list associated
`With IP telephony device 22. Referring noW to FIGS. 1 and
`3, When call manager 26a receives a call initiation request to
`set up a call With IP telephony device 22 (extension 1001),
`call manager 26a may be programmed to ?rst access list 110
`to determine Whether multiple line appearances should be
`created in response to the call initiation request. For
`example, call manager 26a may access list 110 to determine
`at least one other telephony device to ring in addition to IP
`telephony device 22 When IP telephony device 22 is called.
`Alternate number list 110 includes tWo sets of data entries.
`The ?rst set of entries comprises one or more alternate
`numbers 112 to ring When a call comes in for IP telephony
`device 22 at extension 1001. Alternate numbers 112 may
`include, but are not limited to, other IP extensions controlled
`by call manager 26, PBX extensions, and telephone numbers
`of telephony devices on PSTN 60. In exemplary list 110,
`alternate numbers 112 include IP telephony device 23 on
`LAN 20a (at extension 1002), PBX telephony device 55 (at
`extension 2150), PSTN cellular telephony device 67 (at
`214-555-5001), IP telephony device 25 on LAN 20b (at
`extension 3015), and PSTN pager 69 (at 214-555-5003).
`Although extensions and NANP numbers are illustrated in
`list 110, it should be understood that any other identi?er of
`telephony devices may also be used. For the purposes of this
`application, the terms “number,” “extension” or “telephone
`number” should be interpreted generically to mean any
`number, combination of numbers, or other suitable infor
`mation used to identify a telephony device.
`The second set of entries in alternate number list 110
`comprises ring delay times or periods 114 (in seconds or any
`other appropriate unit) that are associated With each alternate
`
`15
`
`25
`
`35
`
`40
`
`45
`
`55
`
`65
`
`8
`number 112. The value of ring delay period 114 informs call
`manager 26 of the length of time to Wait before ringing each
`alternate number. All numbers that have no delay period (or
`a Zero value) are rung ?rst. Call manager 26 then rings the
`other numbers based on their respective delay periods. For
`example, according to alternate number list 110, call man
`ager ?rst Will ring IP telephony device 22 and PBX tele
`phony device 55. Call manager 26 Will then Wait three
`seconds before ringing cell telephony device 67 and IP
`telephony device 25. Finally, call manager Will Wait another
`four seconds before ringing pager 69.
`Non-Zero delay periods may be used for several reasons.
`For example, the user of IP telephony device 22 may only
`Wish to initially ring telephony devices at his main