(12) United States Patent
`Alexander et al.
`
`I IIIII IIIIIIII Ill lllll lllll lllll lllll lllll lllll lllll lllll 111111111111111111
`US006798767Bl
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 6,798,767 Bl
`Sep.28,2004
`
`(54) SYSTEM AND METHOD FOR GENERATING
`MULTIPLE LINE APPEARANCES IN A
`COMMUNICATION NETWORK
`
`(75)
`
`Inventors: John D. Alexander, Plano, TX (US);
`Kenneth P. Pruski, Plano, TX (US);
`Michael H. Mcclung, Alexandria, VA
`(US)
`
`(73) Assignee: Cisco Technology, Inc., 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 O days.
`
`(21) Appl. No.: 09/442,161
`
`(22) Filed:
`
`Nov. 16, 1999
`
`Int. Cl.7 ................................................ H04L 12/66
`(51)
`(52) U.S. Cl. .................... 370/352; 370/401; 379/93.01;
`379/211.02; 379/221.01; 455/445
`(58) Field of Search ................................. 370/352, 353,
`370/354, 355, 356, 389, 400, 401, 522;
`379/88.17, 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
`
`10/1989 Hashimoto
`4,876,707 A
`5,742,905 A * 4/1998 Pepe et al. .................. 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 Bl * 8/2001 Gurbani et al. ........ 379/142.06
`6,304,565 Bl * 10/2001 Ramamurthy ............... 370/352
`
`6,327,267 Bl * 12/2001 Valentine et al. ........... 370/466
`6,327,358 Bl * 12/2001 March et al.
`.......... 379/221.01
`6,359,892 Bl
`3/2002 Szlam
`6,421,339 Bl
`7/2002 Thomas
`6,421,437 Bl * 7/2002 Slutsman ............... 379/201.02
`9/2002 Weitz
`6,445,682 Bl
`6,445,694 Bl
`9/2002 Swartz
`6,449,269 Bl
`9/2002 Edholm
`6,453,034 Bl * 9/2002 Donovan et al.
`... ... 379/220.01
`6,480,484 B2 * 11/2002 Morton ....................... 370/352
`6,515,997 Bl * 2/2003 Feltner et al.
`.............. 370/401
`6,519,252 B2
`2/2003 Salberg
`6,526,033 Bl
`2/2003 Wang et al.
`6,532,286 Bl
`3/2003 Burg
`
`OTHER PUBLICATIONS
`
`Cisco Systems, Inc.; "System Description for the Cisco
`Communications Network Version 2.1;" Cisco Communi(cid:173)
`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(cid:173)
`phony device, and a call manager coupled to the commu(cid:173)
`nication network. The call manager signals the target tele(cid:173)
`phony device to indicate an incoming call from the
`originating telephony device. The call manager includes an
`alternate number list that identifies 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(cid:173)
`ing a network address with each identified alternate tele(cid:173)
`phony device.
`
`34 Claims, 5 Drawing Sheets
`
`10
`'-.,
`
`x2020
`54
`
`x2150
`55
`
`,1001
`22
`
`r-------------------------,
`214-555-5001
`214-555-5002
`
`6h'
`
`68
`
`60_,I
`
`64b
`
`-------------------------~
`
`71
`703-555-8000
`
`YMAX CORPORATION v. FOCAL IP, LLC
`FOCAL IP, LLC EX2051 - 1
`U.S. Patent No. 6,798,767 IPR2016-01260
`
`

`

`r-------------------------,
`214-555-5001
`214-555-5002
`
`671
`~
`
`MOBILE TELEPHONE
`SWITCHING OFFICE
`
`68
`~
`II
`
`214-555-5003
`69
`
`10
`~
`
`52
`
`I GATEWAY
`
`GATEWAY
`
`64a
`
`FIG. 1
`26a, I CALL I
`
`. MANAGER
`
`I
`
`x1001
`22~11r1~11
`
`x1002
`23
`
`30
`
`x2020
`54
`
`x2150
`55
`
`-
`
`ID)
`
`!ill:] -
`IMO
`
`..... a: CXX,Q
`~rn.
`
`I
`I
`I
`I
`I
`60~
`
`42
`1 - - - - -~~~~ - - - 1 GATEWAY 1 - - -~~~ .& - -~~ _ _ ,
`
`""' I=]
`HI
`71
`62c
`703-555-8000
`L-------------------------~
`
`QQQQ
`
`...--
`
`CALL
`26b~ MANAGER
`
`64b
`
`d •
`r:JJ.
`•
`~
`~ .....
`~ = .....
`
`'JJ.
`~ '?
`N
`~CIO
`N
`C
`C
`,i;;..
`
`'JJ. =(cid:173)~
`~ .....
`"'"" 0 ....,
`
`Ul
`
`e
`rJ"J.
`-..a-..
`-....l
`'° ~
`~ a-..
`-....l
`~
`i,-
`
`YMAX CORPORATION v. FOCAL IP, LLC
`FOCAL IP, LLC EX2051 - 2
`U.S. Patent No. 6,798,767 IPR2016-01260
`
`

`

`U.S. Patent
`
`Sep.28,2004
`
`Sheet 2 of 5
`
`US 6,798,767 Bl
`
`FIG. 2
`CALL MANAGER
`
`108,
`
`CONTROL
`SOFTWARE
`I
`
`ADDRESS
`MAPPING TABLE "'- 120
`
`ALTERNATE
`110__/ NUMBER LIST
`
`26
`
`106
`
`PROCESSOR
`
`104
`
`102
`
`110
`~ FIG. 3
`ALTERNATE NUMBER RING DELAY TIME
`1002
`0
`
`2150
`
`112
`
`214-555-5001
`
`3015
`
`214-555-5003
`
`0
`
`3
`
`3
`
`7
`
`114
`
`YMAX CORPORATION v. FOCAL IP, LLC
`FOCAL IP, LLC EX2051 - 3
`U.S. Patent No. 6,798,767 IPR2016-01260
`
`

`

`U.S. Patent
`
`Sep.28,2004
`
`Sheet 3 of 5
`
`US 6,798,767 Bl
`
`120a
`FIG. 4A ~
`DEVICE/GROUP NAME
`PHONE NUMBER
`
`1001
`
`1002
`
`1002
`
`PHONE1
`
`PHONE2
`
`PHONE3
`
`2000-2999
`
`PBXGATEWAY
`
`214-555-5001
`
`GATEWAYGROUP1
`
`214-555-5002
`
`GATEWAYGROUP1
`
`214-555-5003
`
`GATEWAYGROUP1
`
`972-555-6000
`
`3015
`703-xxx-xxxx
`
`GATEWAYS
`
`PHONE25
`
`GATEWAYGROUP2
`
`120b
`FIG. 4B ~
`IP ADDRESS
`DEVICE NAME
`
`PHONE1
`
`PHONE2
`
`PBXGATEWAY
`
`GATEWAY1
`
`GATEWAY2
`
`GATEWAY3
`
`GATEWAYS
`
`PHONE25
`
`GATEWAY10
`
`GATEWAY11
`
`150.100.30.1
`
`150.100.30.2
`
`150.100.30.50
`
`150. 100.30.55
`
`150. 100.30.56
`
`150.100.30.57
`
`150.100.30.58
`
`150.200.70.15
`
`150.200.70.50
`
`• 150.200. 70.51
`
`123
`
`124
`
`122
`
`123
`
`YMAX CORPORATION v. FOCAL IP, LLC
`FOCAL IP, LLC EX2051 - 4
`U.S. Patent No. 6,798,767 IPR2016-01260
`
`

`

`U.S. Patent
`
`Sep.28,2004
`
`Sheet 4 of 5
`
`US 6,798,767 Bl
`
`CALL INITIATED TO
`IP TELEPHONY DEVICE
`
`CALL MANAGER RECEIVES
`REQUEST TO CONNECT CALL
`TO DEVICE ASSOCIATED
`WITH CALLED NUMBER
`
`200
`
`202
`
`FIG. SA
`
`CALL MANAGER RETRIEVES
`IP ADDRESS OF DEVI CE
`ASSOCIATED WITH CALLED
`NUMBER FROM MAPPING TABLE
`
`CALL MANAGER DIRECTS
`CALL TO IP ADDRESS OF
`CALLED TELEPHONY DEVICE
`
`CALL MANAGER SIGNALS
`DEVICE TO RING
`
`204
`
`206
`
`208
`
`210
`
`212
`
`CALL MANAGER QUERIES
`ALTERNATE NUMBER LIST
`
`CALL MANAGER RETRIEVES
`IP ADDRESSES OF DEVICES
`OR GATEWAYS ASSOCIATED
`WITH ALTERNATE NUMBERS
`
`216
`
`CALL MANAGER WAITS
`FOR SPECIFIED PERIOD
`
`NO
`
`CALL MANAGER SENDS
`MESSAGE TO THE APPROPRIATE
`GATEWAY INDICATING
`DEVICE TO BE CALLED
`
`GATEWAY UNPACKS MESSAGE
`TO DETERMINE NUMBER OF
`DEVICE TO BE CALLED
`
`GATEWAY SENDS SIGNALING
`INFORMATION TO CONNECT
`CALL TO ALTERNATIVE DEVICE
`.
`CALLED DEVICE RINGS
`
`224
`
`226
`
`228
`
`230
`
`CALL MANAGER
`DIRECTS CALL TO
`IP ADDRESS OF
`CALLED DEVICE
`
`CALL MANAGER
`SIGNALS DEVICE
`TO RING
`
`220
`
`222
`
`YMAX CORPORATION v. FOCAL IP, LLC
`FOCAL IP, LLC EX2051 - 5
`U.S. Patent No. 6,798,767 IPR2016-01260
`
`

`

`U.S. Patent
`
`Sep.28,2004
`
`Sheet 5 of 5
`
`US 6,798,767 Bl
`
`FIG. 5B
`
`PROCESS OFF-HOOK
`PROCESSING INFORMATION
`
`238
`
`236
`
`240
`
`242
`
`SIGNAL OTHER DEVICES
`TO STOP RINGING
`
`CONNECT CALL TO
`OFF -HOOK DEVICE
`
`RELEASE OTHER DEVICES
`OR PLACE ON KEY HOLD
`
`END
`
`YMAX CORPORATION v. FOCAL IP, LLC
`FOCAL IP, LLC EX2051 - 6
`U.S. Patent No. 6,798,767 IPR2016-01260
`
`

`

`US 6,798,767 Bl
`
`1
`SYSTEM AND METHOD FOR GENERATING
`MULTIPLE LINE APPEARANCES IN A
`COMMUNICATION NETWORK
`
`TECHNICAL FIELD OF THE INVENTION
`
`This invention relates generally to the field of
`telecommunications, and more specifically to a system and
`method for generating multiple line appearances in a com-
`munication network.
`
`BACKGROUND OF THE INVENTION
`
`SUMMARY OF THE INVENTION
`
`Historically, telecommunications have involved the trans(cid:173)
`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 (WAN). Currently, telecommunications and data
`transmissions are being merged into an integrated commu(cid:173)
`nication network using technologies such as Voice over
`Internet Protocol (VoIP). Since many LANs and WANs
`transmit computer data using Internet Protocol (IP), VoIP
`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 30
`( and other voice/data integration technologies) that have not
`been available to users of traditional telecommunication
`networks.
`
`s
`
`10
`
`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
`15 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 specified time
`20 after the target telephony device is rung. A further advantage
`of the present invention includes the ability to remotely
`create and edit a list of alternate telephony devices associ(cid:173)
`ated with a telephony device.
`Other technical advantages are readily apparent to one
`25 skilled in the art from the following figures, 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(cid:173)
`tion with the accompanying drawings, in which:
`FIG. 1 illustrates an exemplary communication network
`35 in accordance with the present invention;
`FIG. 2 illustrates an exemplary call manager in accor(cid:173)
`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(cid:173)
`dance with the present invention;
`FIG. 4B illustrates another exemplary mapping table in
`accordance with the present invention;
`FIG. SA illustrates a first portion of an exemplary method
`of generating multiple line appearance in the communication
`network in accordance with the present invention; and
`FIG. SB illustrates a second portion of an exemplary
`method of generating multiple line appearance in the com(cid:173)
`so munication network in accordance with the present inven(cid:173)
`tion.
`
`45
`
`In accordance with the present invention, a system and
`method for generating multiple line appearances in a com(cid:173)
`munication network is provided that substantially eliminates
`or reduces disadvantages or problems associated with pre- 40
`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(cid:173)
`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(cid:173)
`nication system is provided that includes a communication
`network, and an originating telephony device, a target tele(cid:173)
`phony device, and a call manager coupled to the commu(cid:173)
`nication network. The call manager signals the target tele(cid:173)
`phony device to indicate an incoming call from the
`originating telephony device. The call manager includes an
`alternate number list that identifies at least one alternate
`telephony device to be signaled in response to an incoming
`call directed to the target telephony device. The call manager 55
`additionally includes one or more mapping tables associat(cid:173)
`ing a network address with each identified alternate tele(cid:173)
`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
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`FIG. 1 illustrates an exemplary communication network
`10. Although a specific communication network is illus(cid:173)
`trated in FIG. 1, the term "communication network" should
`be interpreted as generically defining any network capable
`of transmitting telecommunication signals, data, and/or mes-
`60 sages. In the illustrated embodiment, communication net(cid:173)
`work 10 includes a plurality of local area networks (LANs)
`20 interconnected using a wide area network (WAN) 30.
`Each LAN 20 is a computer data network that is further
`operable to transmit audio and/or video telecommunication
`65 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
`
`YMAX CORPORATION v. FOCAL IP, LLC
`FOCAL IP, LLC EX2051 - 7
`U.S. Patent No. 6,798,767 IPR2016-01260
`
`

`

`US 6,798,767 Bl
`
`5
`
`15
`
`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(cid:173)
`priate telephony devices, such as Voice over Frame Relay
`devices, are also included within the scope of this descrip(cid:173)
`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(cid:173)
`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(cid:173)
`sents analog and/or digital telephone systems used by busi(cid:173)
`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 25
`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 offices,
`mobile telephone switching offices, pager switching offices,
`remote terminals, and other related telecommunications
`equipment that are located across the country. For example,
`central offices (COs) 62 connect telephone customers, such
`as residences and businesses, to PSTN 60. In the illustrated
`embodiment, LANs 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(cid:173)
`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
`
`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
`10 telephony device that plugs directly into an Ethernet RJ45
`jack, as opposed to a traditional RJll 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
`20 (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 G.711 and G.723 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
`30 call hold, call transfer and caller ID), device configuration,
`and other telephony functions and parameters within com(cid:173)
`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
`35 example, call manager 26a is capable of controlling tele(cid:173)
`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
`40 20a (an intra-LAN call), the calling telephony device trans(cid:173)
`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
`45 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)
`50 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
`55 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
`60 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
`65 generated by the users of the telephony devices from analog
`voice signals into digital form. The codec may be imple(cid:173)
`mented either in software or as special-purpose hardware in
`
`YMAX CORPORATION v. FOCAL IP, LLC
`FOCAL IP, LLC EX2051 - 8
`U.S. Patent No. 6,798,767 IPR2016-01260
`
`

`

`US 6,798,767 Bl
`
`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(cid:173)
`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(cid:173)
`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(cid:173)
`versa. When voice data packets are transmitted from LAN
`20, gateway 64 retrieves the data contained in the incoming
`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(cid:173)
`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 60
`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, 65
`is continued between PSTN 60 and LAN 20 through gate(cid:173)
`way 64 until the call is complete.
`
`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
`5 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,
`10 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
`15 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
`20 first 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
`25 non-IP telephony device, such as PSTN telephony device 68,
`gateway 64a first 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
`30 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
`35 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
`40 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
`45 used to generically indicate a condition of a telephony
`device when it is ready to initiate or receive telecommuni(cid:173)
`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
`50 originating telephony device. If the originating telephony
`device is a non-IP telephony device, such as PSTN tele(cid:173)
`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
`55 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(cid:173)
`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
`
`YMAX CORPORATION v. FOCAL IP, LLC
`FOCAL IP, LLC EX2051 - 9
`U.S. Patent No. 6,798,767 IPR2016-01260
`
`

`

`US 6,798,767 Bl
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`10
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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 firm(cid:173)
`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 configuration, call set-up, and Web-based admin(cid:173)
`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. A dedicated
`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(cid:173)
`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 first 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 first 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