Exhibit 1004
`
`Z-TE Corporation and ZTE (USA) Inc.
`
`

`
`(12) United States Patent
`Lemiléiinen et al.
`
`(10) Patent N0.:
`
`(45) Date of Patent:
`
`US 6,681,259 B1
`Jan. 20, 2004
`
`US006681259B1
`
`(54) M l<L'l‘H()l) FOR C()UPl.-ING A WlRl<LLl<lSS
`TERMINAL TO A DATA TRANSMISSION
`NETWORK AND A WIRELESS TERMINAL
`
`(75)
`
`Inventors: Jussi Lemiléiinen, Tampere (Fl); Henry
`Haverinen, Tampere (Fl)
`
`(73) Assignee: Nokia Mobile Phones Ltd, Espoo (Fl)
`
`*
`
`Notice:
`
`J
`.
`Sub'ect to anv disclaimer, the term ofthis
`patent is extended or adjusted under 35
`U.S.C. 154(0) by 0 days.
`
`(21) Appl. No.: 09/307,894
`
`(22)
`
`Filed:
`
`May 10, 1999
`
`Foreign Application Priority Data
`(30)
`May 12, 1998
`
`(Fl) ............................................... .. 981052
`
`Int. C17 .............................................. .. G06F 15/16
`(51)
`(52) U.S. C].
`...................................... .. 709/250, 709/227
`(58) Field of Search ............................... .. 709/250, 225,
`709,227, 220, 238, 222, 239, 317, 710/8;
`370/216; 340/71; 455/403; 713/201
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`5,263,178
`5,353,328
`5,392,282
`5,490,235
`5,557,748
`5,630,061
`5,714,943
`5.802351
`5.852.721
`5.862.344
`5,890,005
`5.918.018
`5,983,090
`
`6,003,0973>3>D>>>>>>>>D>D>D>3>
`
`11/1993 Linkkonen ................. .. 455/76
`10/1994 Jokiinies
`379/58
`2/1995
`370/77
`2/1996 Von Holten et al.
`..... .. 395/2.79
`9/1996 Norris ...................... .. 709/220
`5/1997 Richter et al.
`.
`709/227
`2/1998 Rasor ......... ..
`340/7.1
`9/1998 Frainpton
`395/500
`= 12/1998 Dillon el al.
`709/227
`1/1999 Hart
`......................... .. 709/238
`3/1999 Lindholm
`395/750.03
`6/1999 Gooderum el 11].
`709/225
`ll/1999 Aoki
`................. ..
`455/403
`12/1999 Richman et al.
`..
`. 710,/8
`
`:
`
`6.’l31,163 A * '10/2000
`.. . .. 709/222
`6.134,587 A * 10/2000
`370/216
`6,151,297 A * 11/2000 Congdon et al.
`709/222
`..
`6,289,377 B1 *
`9/2001 Lalwaney el al.
`. . . ., 709/220
`6,330,597 B2 * 12/2001 Collin et :11.
`. . . . . . . .
`6.’-184,210 B1 * 11/2002 Adriano el al.
`........... ., 709/239
`
`OTHER PUBLICATIONS
`
`Tripunitara el al, A Middleware Approach to Asynchronous
`& Backvvard Compatible Detction & Prevention of ARP
`Cache Poisoning, IEEE 1999.*
`
`* cited by examiner
`
`Primary Examiner—Mark R. Powell
`Assistant Exam1'ner—Thong V11
`(74) Ar1‘0mey,Ager1t, or FL'rm—Per1nan & Green, LLP
`
`(57)
`
`ABSTRACT
`
`The invention relates to a terminal (A), which comprises at
`least one network interface card (NlCl, NIC2, NIC3) for
`setting up a data transmission connection to a communica-
`tion network (NWl, NW2, NW3, MNW)
`for packet
`switched data transmission, and means (PD) for forming
`packets of the information to be transmitted and for unpack-
`ing information from the received packets. The terminal (A)
`is allocated at least one first address identifying the terminal
`(A), and at least one data network-specific second address.
`The means (PD) for forming packets comprise means for
`connecting the first address to the packets, and the terminal
`(A) also comprises a network interface selection driver
`(NISD), which contains means for selecting the communi-
`cation network (NW1, NW2, NW3, MNW) used in data
`transmission at a given time, means for transmitting packets
`between the means (PD) for forming packets a11d the net-
`work interface card (NlCl, NlC2, NIC3) corresponding to
`the data transmission network (NW1, NW2, NW3, MNW)
`used at
`21 give11 time, and 111ea11s for modifying the first
`address to the second address according to the data trans-
`mission network used in the packets at a given time.
`
`12 Claims, 10 Drawing Sheets
`
`Exhibit 1004-00001
`
`

`
`U.S. Pate11t
`
`Jan. 20, 2004
`
`Sheet 1 of 10
`
`US 6,681,259 B1
`
`ZTE Corporation and ZTE (USA) Inc.
`
`Exhibit 1004-00002
`
`

`
`U.S. Pate11t
`
`Jan. 20, 2004
`
`Sheet 2 of 10
`
`US 6,681,259 B1
`
`ZTE Corporation and ZTE (USA) Inc.
`
`Exhibit 1004-00003
`
`

`
`U.S. Patent
`
`Jan. 20, 2004
`
`01PI.03achS
`
`US 6,681,259 B1
`
`
`
`moo:.m_2%;
`
`Bo:Em:
`
`on.o_.._
`
`o\_as5.v_.n_:
`
`
`
`
`
`zo__.<o_._&<zo_:a:&<mmmoomm
`
`Nnz_awho.88..
`
`ZTE Corporation and ZTE (USA) Inc.
`Exhibit 1004-00004
`
`

`
`U.S. Patent
`
`Jan. 20, 2004
`
`Sheet 4 of 10
`
`US 6,681,259 B1
`
`NETWORK APPUCATION
`
`WINSOCK
`
`SOCKETS EMULATOR-
`
`USER~MODE DU.
`
`SOCKETS EMULATOR-
`
`KERNEL—MODE DRNER
`
`- PROTOCOL DRIVER
`
`NIC DRIVER
`
`USER MODE
`
`KERNEL MODE
`
`TRANSPORT DRNER
`INTERFACE (TDI)
`
`PD
`
`NICD
`
`NETWORK ADAPTER
`
`NIC1. N|C2. NIC3
`
`F|G.3b
`
`NDIS PROTOCOL DRIVER
`
`NDIS INTERMEDIATE DRNER
`
`TDI
`
`PD
`
`NICO
`
`F|G..3c
`
`ZTE Corporation and ZTE (USA) Inc.
`Exhibit 1004-00005
`
`

`
`U.S. Patent
`
`Jan. 20, 2004
`
`Sheet 5 of 10
`
`US 6,681,259 B1
`
`
`
`
`
`UNK—LAYERADDRNEIWORKmunUNK-UAYERADDRnnwonxmore
`
`
`
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`
`
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`
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`swamsemenTARGETTARGET
`
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`I I
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`3E
`§
`
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`
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`
`IEEEam11
`
`UNKLAYER
`
`
`
`TRANSPORTLAYER
`
`
`
`NETWORKLAYER
`
`
`
`
`
`APPLICATIONLAYERBROWSE]?
`
`HARDPROTTYPE
`
`TYPE
`
`Z-TE Corporation and ZTE (USA) Inc.
`Exhibit 1004-00006
`
`

`
`U.S. Patent
`
`Jan. 20, 2004
`
`01f06teehS
`
`US 6,681,259 B1
`
`._
`
`ZTE Corporation and ZTE (USA) Inc.
`
`Exhibit 1004-00007
`
`

`
`U.S. Pate11t
`
`Jan. 20, 2004
`
`01f07tB6hS
`
`US 6,681,259 B1
`
`225
`
`zoEo=&<Ema
`
`8555.&_
`
`52Saw
`
`
`
`a55z<B«L2.8a8eoE
`
`§E&_z_=
`
`ZTE Corporation and ZTE (USA) Inc.
`
`Exhibit 1004-00008
`
`

`
`U.S. Patent
`
`Jan. 20, 2004
`
`t6BhS
`
`01f000
`
`US 6,681,259 B1
`
`.:_c:on_Im3Bm
`
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`
`
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`
`m..m_aEo%=mm_ou£oi
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`85
`
`ZTE Corporation and ZTE (USA) Inc.
`Exhibit 1004-00009
`
`

`
`U.S. Patent
`
`Jan. 20, 2004
`
`c109teehS
`
`04'.
`
`US 6,681,259 B1
`
`
`
` .2_o§_ss__a___mm__.z%%%gEE«E.om_zwas
`
`no.2.5
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`
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`
`ZTE Corporation and ZTE (USA) Inc.
`Exhibit 1004-00010
`
`

`
`U.S. Pate11t
`
`Jan. 20, 2004
`
`Sheet 10 of 10
`
`US 6,681,259 B1
`
`E §E
`
`
`
`REGISTRAITONREQUEST
`
`IPDATAGRAMS
`
`ZTE Corporation and ZTE (USA) Inc.
`
`Exhibit 1004-00011
`
`
`
`PEERCOMPUTER
`
`IPDATAGRAMS
`
`

`
`US 6,681,259 B1
`
`1
`METHOD FOR COUPLING A WIRELESS
`TERMINAL TO A DATA TRANSMISSION
`NETWORK ANI) A WlREI.l<LSS TERMINAI.
`
`BACKGROUND OF TI-IE INVL’.N'I‘ION
`
`invention relates to a wireless terminal
`The present
`according to the preamble of the appended claim 1, and to
`a method according to the appended claim 8, for coupling a
`wireless terminal to a data transmission network.
`
`Considerable growth in the use of computers has
`increased the need for establishing data transmission
`networks, to which these computers are coupled. Especially
`in office use, a local area network, such as the so-called
`Ethernet data network,
`is used as a data transmission
`network,
`to which office computers, printers and other
`corresponding devices are connected. Thus, it is possible to
`use other resources connected to the local area network from
`the computer, for example for printing, wherein it is not
`necessary to provide each computer with such peripheral
`devices. The computer connected to the local area network
`contains a network interface card, or the like, which com-
`prises means necessary for establishing a data transmission
`connection between the computer and the local area net-
`work. Inter-office local area networks are typically imple-
`mented by means of a landline, for example by using a
`so-called thin Ethernet cabling. With the thin Ethernet
`cabling it is possible to achieve a speed of 10 Mb/s, but for
`example with twin cabling, it is possible to use transmission
`speeds of even 100 Mb/s.
`It is also possible to implement the local area network as
`a wireless local area network WLAN. These wireless local
`area networks are typically based on the use of radio
`modems, wherein the office can be included in the range of
`the local area network with one or more such radio modems.
`The computer is equipped with a network interface card,
`which comprises, for instance, a radio transceiver for setting
`up a connection to a radio modem in the local area network.
`In such a wireless local area network, the placement of the
`computers is consirerably freer compared to a fixed landline
`local area network. Such landline local area networks
`intended for office use use in a relatively large bandwidth,
`wherein it is possible to achieve data transmission rates as
`high as 2 Mb/s. In particular, it is easy to connect portable
`computers to such a wireless local area network.
`In addition to the above presented local area network
`solutions, the global Internet data network is known, which
`has recently grown very rapidly in popularity. The afore-
`mentioned loeal area networks can constitute a part of such
`Internet data network, wherein a data transmission connec-
`tion to the Internet data network is set up from the local area
`network LAN, WLAN. Such a data transmission connection
`can be, for example, a modem connection from the server
`computer of the local area network to the server computer of
`Internet operator, or the server computer of the local area
`network can be coupled to form a part of the Internet data
`network.
`
`In connection with portable computers, so-called PCM-
`CIA cards have been developed, which contain built-in
`mobile station features, such as a GSM mobile station and
`peripheral circuits required for data transmission. Thus, it is
`possible to set up a data call from such a wireless data
`processor via the GSM mobile communication network to
`another data processor or even to a local area network of an
`ollice. Previously, a restriction in such data transmission
`utilizing the GSM mobile communication network has been
`
`2
`the relatively low data transmission rate of 9600 bits,/s, but
`solutions capable of faster data transmission are under
`development, such as HSCSD (High Speed Circuit Switched
`Data) and GPRS (General Packet Radio Service). The
`appended FIG. 1 presents in a reduced skeleton diagram the
`aforementioned different network types.
`As portable computers are becoming smaller in size and
`their features are increasing, it has become more and more
`popular to use them also in offices. A portable computer,
`provided with a network interface card intended for use in a
`wireless local area network, can be used as a wireless
`terminal in connection with the wireless local area network
`WLAN. The local area network of an office can consist of
`both a landline local area network LAN and a wireless local
`area network WLAN . For example, upon enlargement of the
`office, a fixed interconnection is not necessarily made for the
`local area network, but
`the extension of the local area
`network is implemented with such a wireless local area
`network solution in the office. In the office,
`the terminal
`could thus primarily use the landline local area network,
`wherein a network interface card for the landline local area
`network is connected to the portable computer. To make
`better mobility possible, a network interface card for the
`wireless local area network is changed in the portable
`computer. At this stage, however, the user of the terminal has
`to terminate the network connections in use at that moment
`and change the network interface card, after which the
`connection to the local area network can be set up again. In
`some situations, it might be necessary to use the terminal
`outside the 0 ice and be connected to the local area network
`of the ofiice. Thus, when using methods and local area
`networks currently known,
`it
`is possible to change the
`network interface card in the portable computer whereby the
`connection can be set up via a mobile communication
`network. Also in this situation it is not possible to change the
`connection by using methods and terminals of prior art
`without terminating the active connections.
`Furthermore, a problem in the different communication
`networks presented above is, for instance,
`that
`in each
`communication network, a different terminal identification
`is used. Dilferences in the terminal identilication used by
`dilferent data transmission networks do not necessarily
`cause inconveniences for the user of the terminal, because
`s/he is always aware of which network s/he is using.
`Nevertheless, when an attempt is made to set up a connec-
`tion to this terminal, the person who sets up the connection
`to the terminal has to know the location in the communica-
`tion network to which the terminal in question is connected
`at a given time. One such connection set-up situation is
`when an attempt is made to set up a call via the Internet data
`network. Another drawback is that the user of such different
`data transmission networks has to monitor the quality of the
`connection. For example, when the user moves inside the
`office and uses the wireless local area network WLAN, in
`some parts of the ollice the quality of the connection may
`become so poor
`that data transmission is disturbed or
`delayed significantly. Thus, the user should try to shift to
`such a data transmission network, in which a better connec-
`tion quality is achieved, for example to a landline local area
`network LAN, if such is in the vicinity, or to the GSM
`mobile communication network, if the user is in its coverage
`area. This change of the data transmission network causes
`the problems described above: termination of the existing
`connections, setting up new connections and, if necessary,
`also cutting off or setting up a telephone connection.
`SUMMARY OF THE INVENTION
`
`It is a purpose of the present invention to provide a
`method for coupling a portable terminal in a flexible manner
`
`ZTE Corporation and ZTE (USA) Inc.
`
`Exhibit 1004-00012
`
`

`
`US 6,681,259 B1
`
`3
`to a data transmission network, and for changing the data
`transmission connection used at a given time to another data
`transmission network when necessary, as well as to a por-
`table terminal according to the method. A wireless terminal
`according to the present invention is characterized in what
`will be presented in the characterizing part of the appended
`claim 1. A method according to the present invention is
`characterized in wh at will be presented in the characterizing
`part of the appended claim 8. The invention is based on the
`idea that
`the network layer address (IP address) of the
`terminal and the link layer addresses used by the different
`network interface solutions available in the terminal are
`combined in the terminal.
`
`With the present invention, significant advantages are
`achieved, compared to methods and terminals of prior art.
`The embodiment according to the invention makes it pos-
`sible to supplerrrent the operating system used in the termi-
`nal with the functionality of a mobile terminal, without a
`need to make changes in the operational modules of the
`operating system or in the network interface software. Thus,
`such a multi-mode terminal can be used in several local area
`
`types and in other communication
`networks of different
`networks, and even in such a way that the communication
`network used at a given time can be changed without
`terminating active connections. This transition can be
`arranged to be conducted in such a way that the user does not
`even notice the transition. Thus, it is possible to use one
`network layer address in the terminal, wherein it is not
`necessary for the applications used in the terminal to know
`which physical data transmission network is used at a given
`time. This invention also makes it possible to use of all the
`data transmission networks available at a time,
`the data
`transmission network, in which the best possible connection
`quality is achieved. In addition, when the quality of the
`connection possibly becomes poor,
`the data transmission
`network can be changed to another data transmission “
`network, in which a better connection quality is possibly
`achieved at that moment. Also, the user of the terminal
`according to the invention can always be communicated
`without the initiator of the communication having to know
`to which data transmission network the terminal is coupled
`at a given time.
`BRIEF DESCRIPTION OF TIIE DRAWING
`
`In the following, the invention will be described in more
`detail with reference to the appended figures, in which
`FIG. 1 shows in a reduced skeleton diagram some net-
`work types, in which the invention can be advantageously
`applied,
`FIG. 2 shows a terminal according to an advantageous
`embodiment of the invention in a reduced block diagram,
`FIG. 3a shows the structure of an operating system in a
`reduced manner,
`FIG. 3b shows the network architecture of an operating
`system in a reduced manner,
`FIG. 3C shows the network controller interface of the
`network architecture according to FIG. 3b in a reduced
`manner,
`
`FIG. 4 shows the coupling of and data transmission
`between two terminals in different functional layers,
`FIG. 5 shows an advantageous example of the message
`structure of the address resolution protocol ARP,
`FIG. 6 shows the network architecture of a system, in
`which it is advantageous to apply the invention,
`FIG. 7 shows the functionality of a terrrrin al according to
`an advantageous embodiment of the invention in a reduced
`manner,
`
`4
`FIG. 851 is an arrow diagram showing data transmission in
`a terminal according to an advantageous embodiment of the
`invention,
`FIG. 8b is an arrrow diagram showing data reception in a
`terminal according to an advantageous embodiment of the
`invention, and
`FIG. Sc is an arrow diagram showing the change of a data
`transmission network in a terminal according to an advan-
`tageous embodiment of the invention.
`
`DE'lAlLED DESCRIPTION Ol’ THE
`INVENTION
`
`In the following, the invention will be described by using
`as an example of the mobile terminal a portable computer,
`which is presented in a reduced block diagram in FIG. 2. The
`operating system in the computer is the Windows® NT
`operating system developed by Microsoft Corporation, but it
`is obvious that the invention can be applied also in connec-
`tion with other operating systems. Furthermore, in a terminal
`A there are several network interface adapters NIC1, NIC2,
`NIC3 available for coupling to data transmission networks
`of dilferent types, of which an Ethernet type landline local
`area network, a wireless local area network WLAN accord-
`ing to the IEEE standard 802.11, and a GSM mobile
`communication network are mentioned as examples, but
`also other data transmission solutions, such as the packet
`switched data transmission system GPRS (General Packet
`Radio Service) of the GSM system and LPRF (Low Power
`RF) based on a low power radio signalling, can be applied
`in connection with the present invention. Such terminal A is
`also called a multi-mode terminal.
`
`The appended FIG. 3a presents in a reduced manner the
`structure of the Windows NT operating system. The lower-
`most
`level contains the actual hardware part, which is
`controlled by means of operating system functions and
`drivers connected to the operating system. The hardware
`part includes, for instance, a microprocessor ,uP, memory
`means MEM, a connection logic 1/0, a display device D, and
`a keyboard K. For controlling the drivers,
`the operating
`system contains an l/'0 manager, which conducts,
`for
`instance,
`the start-up of the drivers and attends to the
`communication between the drivers and the rest of the
`operating system or other applications. Particular operating
`system functions, and a large part of the driver functions are
`conducted in a so-called kernel mode. Part of the operating
`system functions and the application programs started by the
`user are set
`to operate in a so-called user mode. The
`applications operating in this user mode have nrore restricted
`operating possibilities; for example, part of the memory
`space and processor instructions are available solely in the
`kernel mode, which is art known as such by anyone skilled
`in the art. Hereinbelow, for the purpose of understanding the
`present invention, this description focuses primarily on the
`network interface architecture, i.e. the function of the net-
`work interface card, network interface drivers, operating
`system network interface functions and application pro-
`grams. FIG. 31') presents as an example the network interface
`architecture of the Windows NT operating system in a
`reduced manner.
`
`The network interface architecture comprises a network
`interface card NIC, by means of which the actual physical
`data transmission connection is established. The network
`interface card is, for example, an Ethernet network interface
`card or a PCMCIA type WLAN network interface card. The
`practical
`implementation of this network interface card
`depends for instance, on the type of network interface in
`
`

`
`US 6,681,259 B1
`
`5
`question. For example, a network interface. card intended for
`a wireless local area network comprises a radio modem, or
`the like, whereby it is possible to set up a wireless data
`transmission connection to the radio modem of the local area
`
`network. Correspondingly, when connecting to the GSM
`mobile communication network, the network interface card
`comprises either a data interface to the mobile station (e.g.
`Nokia Cellular Data Suite), through which the data trans-
`mission connection is set up, or the network interface card
`can also comprise a mobile station transceiver for setting up
`a connection to the mobile communication network (e,g.
`Nokia Cellular Card Phone). Thus,
`the network interface
`card constitutes said physical layer and can also contain
`features of the link layer.
`for
`The network interface card driver NICD attends,
`instance,
`to controlling the network interface card NIC1,
`NIC2, NIC3 and transmitting data between the network
`interface card NlC1, NIC2, NIC3 and the protocol driver
`PD. The network interface card NIC1, NIC2, NIC3, and the
`network interface driver NICD constitute the layers of the
`lowermost level in the protocol stack,
`The network interface card driver NICD communicates
`with the protocol driver PD. The protocol driver PD
`implements, in this advantageous embodiment, the network
`layer and the transport layer of the protocol stack. The
`protocol driver PD uses services of the network interface
`card driver NICD in data transmission. The protocol driver
`PD, for instance, forms the information to be transmitted
`into packets which correspond to the link layer used at a
`given time, and are transmitted by the protocol driver PD to
`the network interface card driver NICD.
`
`The upper level interface of the protocol driver PD forms
`a so-called transport driver interface TDI. This is provided
`with emulator applications (e.g. sockets emulator), or the
`like, whereby for instance a telecommunication application,
`such as a Windows browser program (WEB browser), can
`communicate with the protocol driver PD.
`For applying different data networks, network driver
`interface specifications NDIS are implemented in the Win-
`dows NT operating system, for the purpose providing the
`functional features common to the drivers of the data
`communication networks of different
`types. Thus,
`the
`hardware-specific and protocol-specific parts are imple-
`mented in the lower level network drivers. FIG. 3c presents
`an architecture according to such a network driver interface
`specification, which is located between the driver interface
`of the transport layer and the network interface card, and
`which is marked with NDIS in this description. This NDIS
`network interface architecture is advantageously composed
`of three kinds of drivers: NDIS protocol drivers, NDIS
`intermediate drivers and NDIS network interface card (N IC)
`drivers. The terminal contains typically a separate network
`interface card driver NICD for each network interface card,
`which communicates with the network interface card driver
`and the upper level drivers, wherein it is not necessary for
`the upper level drivers to know which data transmission
`network the terminal A is connected to at a given time.
`Hereinbelow, a shorter term NIC driver will be used for
`these network interface card drivers D1, D2, D3 and they
`will be marked with the references D1, D2, D3.
`In the Internet data network, a TCP/IP protocol stack is
`generally used, which can be divided into five functional
`layers. These five layers are, listed from bottom to top: the
`physical
`layer (Layer 1),
`the link layer
`(Layer 2),
`the
`network layer (Layer 3), the transport layer (Layer 4), and
`the application layer (Layer 5). All the nodes of the Internet
`
`6
`data network contain at least the first three layers. Of these
`nodes, routers, which are primarily responsible for the
`couplings of the data network, do not need the transport and
`application layers. However, hosts, between which the
`actual data transmission connection is set up, contain all the
`said five layers. The appended FIG. 4 presents by means of
`the TCP/IP protocol stack the coupling of and communica-
`tion between two such hosts A, B via a router R. Even
`though all the upper level layers use the services of the
`underlying layer for data transmission, logically the corre-
`sponding layers of the hosts A, B communicate with each
`other by using the protocol typical for the layer. The arrows
`in the appended FIG. 4 illustrate this communication at the
`layer level.
`The TCPIIP protocols can be used in a variety of network
`solutions, such as the packet switched Ethernet and in the
`Token ring network, or in a switched network, such as ATM
`and ISDN. In a connection according to FIG. 4, the data
`transmission between the first host A and the router R is
`conducted in a wireless manner. Data transmission between
`the router R and the second host B is conducted by means
`of a landline Ethernet network, but it is obvious that these
`network solutions only act as examples here. The Institute of
`Electrical and Electronics Engineers IEEE has developed a
`standard 802.11 for wireless local area networks. In the
`connection of FIG. 4, data transmission according to this
`standard 802.11 is used between the host device A and the
`router R.
`
`In the following, the meaning of these different protocol
`stack layers will be described briefly. The actual data trans-
`mission is conducted in the. physical layer by using a data
`transmission means, such as a wireless radio network or
`landline cabling.
`The link layer attends to solutions required by different
`network technologies, wherein the upper level layers do not
`have to know how the data transmission network used at a
`given time is constructed. The link layer processes different
`addressing and frame modes and is responsible for the data
`transmission between two terminals in the same communi-
`cation network.
`
`The task of the network layer is to route packets between
`terminals in the communication network. The network layer
`provides the coupling between different data networks,
`wherein the upper level layers do not have to know about the
`structure of the data network, On this network lay'er level,
`for instance protocols IP (Internet Protocol), ICMP (Internet
`Control Message Protocol) and IGMP (Internet Group Man-
`agement Protocol) are used.
`The transport layer provides a generic end-to-end data
`transmission connection for the application layer. The appli-
`cation layer uses for instance a TCP protocol (Transmission
`Control Protocol) and a UDP protocol (User Datagram
`Protocol). In the example of FIG. 4,
`the terminals A, B
`communicate with each other in the transport layer by using
`packets according to the TCP protocol.
`The application layer protocols operate above the trans-
`port layer and provide application-specific services, such as
`file transfer services or local area network remote login
`services. In the example of FIG. 4, the hosts A, B use a
`so-called HTTP protocol (lIyperText Transfer Protocol)
`which is generally used in the Internet data network for
`loading and presenting the data contained in so-called home
`pages in the display device of a computer. For this purpose,
`in the example of FIG. 4,
`the first host A is running a
`so-called web browser program, which transmits a request to
`the Internet web server of the second host B. This Internet
`
`ZTE Corporation and ZTE (USA) Inc.
`
`Exhibit 1004-00014
`
`

`
`US 6,681,259 B1
`
`7
`web server replies to the request by sending the contents of
`the requested home page in HTTP messages. This home
`page is composed, for example, by means of hypertext
`mark-up language HTMI.. Other application layer protocols
`include Telnet, the file transfer protocol FTP and the simple
`mail transfer protocol SMTP.
`In the Internet data network, each terminal or host has its
`own identifying IP address. The IP address is in the Internet
`protocol version IPV4 a 32 bit, i.e. 4 byte number which is
`split into an organization-specific network address and a
`network-specific device address. In a newer Internet proto-
`col version IPv6, the length of the address fields is increased
`to 128 bits, which, in practice, means that it is possible to
`allocate an individual address for all the devices which are
`connected to the Internet data network. An Internet host
`connected to the Internet data network via a local area
`
`network LAN, WLAN has either a permanently specified
`Internet address or the address is a dynamic address estab-
`lished by the local area network server (for example by using
`dynamic host configuration protocol DIICP). If the Internet
`host is connected to a telecommunication network via a
`modem, the host has to request for an Internet address from
`the Internet service provider, to which the Internet host is
`registered, This is conducted, for example, according to a
`point-to-point protocol PPP, In both cases, the data is routed
`in the Internet to the Internet host from a remote terminal,
`possibly via several communication networks and route rs by
`rising the specified Internet address.
`The Internet protocol IP specifies the data transmission in
`packets (“Datagrams”). When a host or a router receives a
`packet on the IP level, either from the data network or from
`an upper level of the protocol stack,
`the first step is to
`examine whether the packet is intended precisely for the
`router or terminal
`in question. If the packet is intended
`precisely for this router or terminal, the packet is transferred _
`from the network layer to the upper layer in this node. If the
`packet
`is intended to another node, a so-called routing
`algorithm is executed in the network layer for concluding
`how the packet should be processed. First, it is examined
`whether the packet is intended for another node in the same
`network. If this is the case, the node can transmit the packet
`to the destination address by using the mechanisms of the
`link layer. Thus, the IP address of the network layer level is
`connected to the corresponding link layer address by using
`the so-called address resolution protocol ARI’, which will be
`described below in this description. In this node, the packet
`is also framed into a packet corresponding to the link layer
`and transmitted further.
`
`_
`
`If the packet is intended for another network, the routing
`algorithm runs through a routing table in order to find o11t to
`which address the packet should be transmitted. The routing
`table typically contains a so-called default address, to which
`all such packets are transmitted whose routing address
`cannot be found in the routing table.
`The situation of FIG. 4 can be used as an example of the
`above described routing, in which the first host A and the
`second host B communicate with each other via the router R.
`In the situation where the first host A has a packet to transmit
`to the second host B, the routing algorithm detects that the
`destination address of the packet is not located in the same
`network as the first host A. Thus, the routing algorithm starts
`running through the routing table and finds the data of the
`correct router R. Thus, the first host A transmits the packet
`to the router by using, for example, data transmission
`according to the IEEE 802.11 standard. The router R
`receives the frame, unpacks its content and examines from
`it
`the header according to the network layer packet. The
`
`8
`router is located in the same network as the second host B,
`wherein the router R can transmit the packet directly to the
`second host B by using Ethernet data transmission.
`The transmission of IP packets between different coupled
`data networks on the network layer level is conducted on the
`basis of IP addresses. In addition to the IP addresses, the
`devices connected to the Internet data network also have a
`so-called link layer address, which is also called a device
`address. Because terminals use link layer services in packet
`transmission with terminals connected to the same data
`network, the terminals need the address resolution protocol
`ARP for connecting the IP addresses to the corresponding
`link layer addresses. The reverse address resolution protocol
`RARP connects the link layer addresses to the corresponding
`IP addresses. The function of the address resolution protocol
`ARP depends on the structure of the data transmission
`connection used at a given time. For example, the s