United States Patent 11
`4,788,637
`Tamaru
`Nov. 29, 1988
`[45] Date of Patent:
`
`(11) Patent Number:
`
`[54] COMMUNICATION CONTROL APPARATUS
`[75]
`Inventor:
`(73] Assignee:
`
`Kiichiro Tamaru, Tokyo, Japan
`Kabushiki Kaisha Toshiba, Kawasaki,
`Japan
`
`[21] Appl. No.: 912,516
`[22] Filed:
`Sep. 29, 1986
`
`Foreign Application Priority Data
`[30]
`Sep. 30, 1985 (JP]
`Japan .acecccsssscecsessssseeseeen 60-216840
`
`4,484,263 11/1984 Olson et al. oo... 364/200
`
`4,558,413 12/1985 Schmidt et al.
`. 364/300
`4,742,516
`5/1988 Yamaguchi.
`...........ccccceeee 370/94
`OTHER PUBLICATIONS
`
`Mano, M. M., Computer System Architecture, N.J. Pren-
`tice-Hall, 1982, pp. 18-20, 328-338 and 462-473.
`Primary Examiner—Gareth D. Shaw
`Assistant Examiner—Joseph T. Fitzgerald
`Attorney, Agent, or Firm—Foley & Lardner, Schwartz,
`Jeffery, Schwaab, Mack, Blumenthal & Evans
`
`Inti Olt sccscsicccccai GO06F 13/00; HO4J 3/24
`[Sl]
`
`[52] U.S. C1. eee cceeeeseteeeeenseeee 364/200; 370/94
`
`(58] Field of Search ............::00 370/90, 91, 92, 93,
`370/94, 95; 364/200 MSFile, 900 MSFile
`
`[56]
`
`ABSTRACT
`(57]
`A communication control apparatus wherein the ver-
`sion number of a communication control program in a
`packet accepted by a receive circuit is compared at a
`References Cited
`comparator with that of the local station. When the
`version for the local station is determined to be older
`U.S. PATENT DOCUMENTS
`than the version for the remote station, the apparatus
`4,060,849 11/1977 Bienvenuet al.
`.....ccsesceens 364/200
`- 364/300
`receives the latest communication control program
`4,309,756
`1/1982 Beckler ............
`from the remote station and stores it
`in a rewritable
`Sena a
`We
`on
`4,320,520 3/1982 Graham .......
`ve 370/92
`
`
`4,410,889 10/1983 Bryantet al. ..esccccsssssseessseeeee 370/9q4sMemory, thereby allowing communication using (the
`
`
`4,425,618 364/300_latest version.1/1984 Bishopet al.....
`
`
`2/1984 Bryantet al. coccsccccsscssssssseee 370/94
`4,430,651
`4,477,898 10/1984 Cholat-Namy ou...370/92
`
`8 Claims, 5 Drawing Sheets
`
`VERSION
`
`TO COMPUTER
`NETWORK
`
`2
`
`3
`
`OMPA Z COMPARATOR }[CONTROLLER
`
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`Apple v. PMC
`IPR2016-01520
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`
`
`US. Patent—Nov. 29, 1988 Sheet 1 of 5 4,788,637
`
`
`
`TO COMPUTER
`NETWORK
`
`2
`
`3
`
`UNIT
`
`STORAGE
`
`
`
`DATA FIELD
`
`
`
`2|
`23
`26
`
`
`DESTINATION
`VERSION
`DATA
`
`NUMBER
`STATION
`LENGTH
`ADDRESS
`
`22
`24
`SOURCE
`DATA TYPE
`STATION
`ADDRESS
`
`FIlG.2
`
`27
`CHECK
`FIELD
`
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`IPR2016-01520
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`

`

`US. Patent
`
`Nov.29, 1988
`
`Sheet2 of 5
`
`4,788,637
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`Apple v. PMC
`IPR2016-01520
`Page 3
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`Apple v. PMC
`IPR2016-01520
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`

`

`US. Patent
`
`Nov. 29,1988
`
`Sheet 3 of 5
`
`4,788,637
`
` F1G.4 VERSIONNUMBER;~-202
`
`
`
`LOCALSTATION
`
`HOLDCIRCUIT
`
`"O"DETECTOR VERSION
`
`NUMBERHOLDCIRCUIT
`
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`2|4
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`IPR2016-01520
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`Nov. 29, 1988
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`PMC Exhibit 2120
`Apple v. PMC
`IPR2016-01520
`Page 5
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`PMC Exhibit 2120
`Apple v. PMC
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`

`Nov.29, 1988
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`PMC Exhibit 2120
`Apple v. PMC
`IPR2016-01520
`Page 6
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`PMC Exhibit 2120
`Apple v. PMC
`IPR2016-01520
`Page 6
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`

`

`1
`
`4,788,637
`
`COMMUNICATION CONTROL APPARATUS
`
`BACKGROUNDOF THE INVENTION
`
`Thepresent invention relates to communication con-
`trol apparatus, especially, used in computer networks.
`Computer networks in which computers are con-
`nected by communication lines to make mutual ex-
`changeof information possible are increasing steadily.
`In this computer network, computers are connected
`via communication control devices to communication
`lines in order to determine a procedure to perform com-
`munication and to accurately control timing for trans-
`mission and receiving.
`The communication control device is controlled by a
`communication control program. There are various
`versions of a communication control program depend-
`ing upon the performance of the function improvement
`or debugging.
`On the other hand, communication control programs
`are individually updated for the respective communica-
`tion control devices constituting the computer network.
`Thus when transmission from onestation to another
`is to be performed,there exists a situation where com-
`munication may be impossible because ofdifferent ver-
`sions of a program. Especially, when a new station is
`added to the computer network, a version of a commu-
`nication control program for the communication con-
`trol device of the newly added station is not consistent
`with those for other stations, resulting in the possibility
`that connection will be difficult.
`In order to improve sucha situation, a method has
`been developed in which a function such that communi-
`cation between different versions of a communication
`program is enabled is provided by the communication
`control program itself. There is, however, the problem
`with this method that the process for executing the
`communication control program becomes complicated.
`Another method is that both the communication con-
`trol programs for the communication control devices
`which are intended to communicate therebetween are
`updated simultaneously. According to this method,
`however, simultaneous updating of both the programs
`is required, so that the entire computer network must be
`stopped at that time, giving rise to the problem that
`communication efficiency is lowered.
`SUMMARY OF THE INVENTION
`
`It is an object of the present invention to provide a
`communication control apparatus wherein even when
`versions of a communication control program for
`source and destination stations are different, connection
`free from problems can be made.
`It is another object of the present invention to pro-
`vide a communication control apparatus which permits
`communication between communication control pro-
`grams of differenct versions without using a compli-
`cated communication control function.
`It is a further object of the present invention to pro-
`vide a communication control apparatus which permits
`good communication even whena newstation is added.
`In orderto attain the above objects, a communication
`control apparatus according to the present invention
`includes a transmit-receive circuit connected to a com-
`puter network so as to communicate betweenthe local
`station and other remote stations, a rewritable storage
`unit in which a communication program is stored, a
`comparison unit for determining whether or not a ver-
`
`5
`
`10
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`
`30
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`2
`sion number of a communication control program in a
`packet accepted by the transmit-receive circuit is newer
`than that of the communication control program stored
`in the storage unit, and a controller for allowing the
`local station and a remote station to communicate there-
`between using a communication control program of the
`latest version compatible therebetween on the basis of
`the output of the comparison unit. This allows smooth
`communication between stations where different ver-
`sions of the program are used.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`In the accompanying drawings:
`FIG. 1 is a block diagram showing the configuration
`of an embodimentof a communication control appara-
`tus according to the present invention;
`FIG. 2 showsa formatof a packet used in the present
`invention;
`FIG. 3 is a block diagram showing the details of a
`transmit-receive circuit and a version comparator in
`FIG.1,
`FIG. 4 is a diagrammatical view showing a more
`detailed configuration of the version comparator;
`FIGS. 5 to 8 illustrate the operation of the communi-
`cation control apparatus according to the present inven-
`tion; and
`FIG. 9 is a flowchart showing the entire operation of
`the communication control apparatus according to the
`present invention.
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`
`FIG.1 is a block diagram showing the configuration
`of a communication control apparatus according to the
`present
`invention. As seen from FIG. 1, a transmi-
`treceive circuit 1 is connected via a transmit-receive
`signal
`line 6 to a computer network. The transmi-
`treceive circuit 1 is also connected via an internal data
`bus 10 to a storage unit 4 comprised of a rewritable
`memory in which the communication control program
`is stored, and to a data buffer § which is connected via
`an interface bus 13 to a host computer (not shown). The
`transmit-receive circuit 1 and the data buffer 5 are con-
`trolled via a controlsignal line 12 by a controller 3. The
`communication control program is supplied via a con-
`trol program read bus 9 from the storage unit 4 to the
`control circuit 3. A version comparator 2 is provided
`between transmit-receive circuit 1 and controller 3. The
`version number of a communication control program
`on the transmit side in a packet received is delivered via
`a transmission-side version number data line 7 to the
`version comparator 2. At this version comparator2, the
`accepted program version numberis compared with the
`program version numberfor the local station supplied
`via a control program version number data line 11 from
`storage unit 4. It is to be noted that the local station is
`defined as station localized separately from other re-
`mote stations in the area where this communication
`control apparatus is provided. The result is delivered
`via a version comparison result signal line 8 to the con-
`troller 3 which in turn performs a predetermined con-
`trol in accordance with the version comparison result,
`as will be described later in more detail.
`FIG. 2 shows an example of a packet which can
`operate the control apparatus according to the present
`invention, the packet 20 consists of a header field in-
`cluding information indicating a destination station ad-
`
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`4,788,637
`
`3
`dress 21, a source station address 22, a version number
`23, a data type 24 and a data length 25; a data field 26
`nest thereto; and a check field 27 including a failure
`detection code etc.to be finally transmitted. The infor-
`mation indicating the version number 23 in the packet
`20 will be read by the transmit-receive circuit 1 and
`compared at the version comparator2.
`FIG.3 is a block diagram showing thedetails of the
`transmit-receive circuit 1 and the version comparator2.
`The packet 20 input via the transmit-receive signal line
`6 to the transmit-receive circuit 1 is demodulated by a
`demodulator 101, and the received or accepted destina-
`tion station address 21 in the header field is held by a
`destination station address hold circuit 102. Theoutput
`from the hold circuit 103 is compared by an address
`detector 104 with the output from a local station ad-
`dress hold circuit 103 in which the local station address
`is stored in advance. The result of the comparison is
`supplied to the controller 3. The version number 23 in
`the received packet 20 is held by a version numberhold
`circuit 105, the output of which is compared with the
`local station version number held by a local station
`version numberholdcircuit 202 at a version comparing
`unit 201 in the version comparator 2. The result of the
`comparisonis delivered to the controller 3 via the ver-
`sion comparison result signal line 8. Each of hold cir-
`cuits 102, 103, 105 and 202 is constituted with a latch,
`for example. The address detector 104 is only required
`to detect coincidence or noncoincidence, so that it can
`be easily implemented by an exclusive OR gate.
`FIG. 4 shows an example of the configuration ofthee
`version number comparing unit 201 where the version
`number is shown as being composed ofn bits, for exam-
`ple, 8 bits. The comparing unit 201 is basically com-
`prised of an n-bit full adder 211 which adds the version
`numberof the remote station program held by version
`number hold circuit 105 and the local station program
`version numberheld by the local station version num-
`ber hold circuit 202 and then inverted by an inverter
`212, and outputs the result in the form ofan n-bit signal.
`The carry signal from the least significant or rightmost
`position is input to the adder while carry of the most
`significant or leftmost position is output on a line 215. A
`zero detector 213 detects whether or not the outputbits
`of the full adder 211 areall “0” and outputs the result on
`a line 214.
`the full adder
`In the version comparing unit 201,
`outputbits becomeall “0” by the carry when the local
`station and remotestation versions are completely coin-
`cident with each other and the output of the zero detec-
`tor 213 becomes “1”. Thus when the signal on a line 214
`is “1”, the version numbers of the local station and the
`remotestation are equal whereas when the signai on the
`line 214 is “0”,
`the version numbers are different.
`Namely, it is determined whether or not the local sta-
`tion program version number is newer than the remote
`station version number.
`In the case wherethe local station versionis different
`from the remote station version, when the carry output
`is “0”, the local station version is determined to be older
`than the remote station version. In contrast, when the
`carry output is “1”, the local station version is deter-
`mined to be newer than the remote station version.
`FIGS. 5 to 8 illustrate aspects of communication
`using the communication control apparatus according
`to the present invention where it is assumed in these
`Figures that time passes downward from the top and
`
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`4
`that data is transferred from the sourcestation (1) to the
`destination station (2).
`FIG.5 illustrates a case where there is no difference
`in version number between the stations (1) and (2).
`Normal transmission TR is performed from the station
`(1) to the station (2). When transmission and receiving
`have been completed,the station (2) sends an acknowl-
`edgementsignal ACK back tothe station (1). The con-
`tents of this acknowledgement signal ACK may be
`stored in advancein the storage unit 4.
`FIG.6 shows that the program versionofthe station
`(1) is newer than that of thestation (2).
`The transmission packet on the station (1) side is
`formed so as to include the version number, as shownin
`FIG. 2, On the station (2) side, the version number in
`the packet accepted by the transmit-receive circuit 1
`and stored once in the data buffer 5 is delivered from
`the transmit-receive circuit 1 to the version comparator
`2, At this comparator 2, the accepted version numberis
`compared with the version number of the communica-
`tion control program stored in the storageunit4, so that
`the version of the station (2) is determined to be older.
`The controller 3 then sends to the station (1) a message
`requesting to transfer the newer version of communica-
`tion control program. Another message sent simulta-
`neously this time may be either to the effect that the
`transmission has once been accepted orto the effect that
`the transmission cannot be accepted due to version
`difference. In response to a request for transfer of the
`newer version by thestation (2), the station (1) reads the
`newer version of communication control program out
`of the storage unit 4 and transfers it to the station (2).
`This causes the contents of storage unit 4 on the station
`(2) side to be rewritten with the newer version of com-
`munication control program. At the same time, an ac-
`knowledgementsignal ACKis outputto the station (1).
`FIGS. 7 and 8 show that on the contrary the station
`(2) program version is newer than the station (1) ver-
`sion. In FIG. 2, when transmission is performed from
`the station (1) to the station (2), the station (2) outputs
`an acknowledgement signal ACK and concurrently
`informs station (1) that the station (1) version is older.
`Upon reception of this, the station (1) sends a request
`for transfer of the newer version and the station (2)
`transfers the newer version to the station (1). In con-
`trast, in FIG. 8, when the version for the station (1)is
`determined to be older, the station (2) forcedly transfers
`to the station (1) the newer version of communication
`control program.
`FIG. 9 is a flowchart showing the operation of con-
`troller 3 corresponding to that of the communication
`control apparatus of FIGS. 5 to §. First,
`in the case
`where the local station program version is determined
`to be older than the remote station program version on
`the basis of the result of comparison of the version
`numbers, when the communication control program is
`received (step 311), the newer version is selected (step
`312) and a newer-version acknowledgement (ACK)
`signal is sent (step 313). When no communication con-
`trol program is received, a request for transfer of the
`newer version is sent (step 314). On the other hand,in
`the case where the local station side has the newer
`version, when transmission of the newer version is re-
`quested by the remote station (step 331),
`the newer
`version is transmitted to the remote station (step 332).
`Particularly, when no transmission is requested,
`the
`remotestationis informed that the versionis older (step
`334). When the versions for the local station and the
`
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`IPR2016-01520
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`4,788,637
`
`5
`remote station are the same, the presence of a request
`for transmission of a newer version is once checked
`(step 321). When the presence of the request is deter-
`mined, a negative acknowledgement signal (NAK)is
`sent (step 322). In contrast, when there is no request for
`transmission of the newer version, a packet acknowl-
`edgementsignal (ACK)is sent to the remote station
`(step 323).
`While in the above embodimentthe version compara-
`tor is provided separately, it is not necessarily required
`that it is so. What is required is only to include the
`function of the comparator. For example, the controller
`can perform such function.
`It should be noted that the configuration of the re-
`spective blocks of the apparatus should notbe limited to
`those of the embodiment shown. Any elements may be
`used if they have functions similar to those of the blocks
`disclosed.
`The packet may take another format different from
`that shown in the embodiment if it includes version
`information somewhere therein.
`As described above, the present invention includes a
`comparatorin which the version number of the commu-
`nication control program for the local station stored in
`a storage unit is compared with that for the remote
`station accepted by the transmit-receive circuit, and a
`controller which updates the program on the basis of
`the output from the comparator. Thus updating is possi-
`ble as needed without stopping the computer network.
`In addition, no special consideration is required for
`improving a version of a communication control pro-
`gram, thereby reducing the labor spent for the develop-
`ment of programs.
`Whatis claimed is:
`1. A communication control apparatus provided in
`each computer system for communication between
`computer systems linked by a computer network com-
`prising:
`a transmit-receive circuit connected to said computer
`network so as to communicate between a local
`station and other remote stations;
`a reprogrammable storage unit in which a commu-
`nication program is stored;
`a comparison unit connected to said transmi-
`treceive circuit for comparing a version number
`of a communication control program in a packet
`accepted by said transmit-receive circuit with
`that of the communication control program
`stored in said storage unit and outputting com-
`parison results as to which program is of the
`latest version; and
`a controller connected to said comparisonunit, said
`transmit-receive circuit and said storage unit, for
`performing communication between said local
`station and a remote station using a communica-
`
`6
`tion control program ofthe latest version com-
`patible therebetween on the basis of an output of
`said comparison unit.
`2. A communication control apparatus as set forth in
`claim 1, wherein said transmit-receive circuit includes a
`version number hold circuit for holding the version
`number of the communication control program in the
`packet received so as to transmit the version number to
`the comparison unit.
`3. A communication control apparatus as set forth in
`claim 2, wherein said version number hold circuit is
`comprised ofa latch.
`4. A communication control apparatus as set forth in
`claim 1, wherein said comparison unit is comprised of
`an n-bit full adder for adding the version numberof a
`communication control program for the remote station
`and an inverter for obtaining the inverted number of a
`communication control program for the local station so
`as to output a signal representing coincidence/noncoin-
`cidence between the version numberof the communica-
`tion control program for the remote station and that of
`the communication control program for the local sta-
`tion and outputs carry signal representing which ver-
`sion is newer in the case both the version numbers are
`not coincident with each other.
`5.A communication control apparatus as set forth in
`claim 1, wherein said controller is of a type which re-
`quests the remote station to transfer to the local station
`the newer version of communication control program
`when the program version for the local station is older
`than the program version for the remote station, and
`informs the remotestation that the program version for
`the remotestation is older.
`6. A communication control apparatus as set forth in
`claim 1, wherein said controller is of a type which re-
`quests the remotestation to transfer to the local station
`the newer version of communication control program
`when the program version for the local station is older
`than the program version for the remote station, and
`forcedly transfers to the remote station the newer ver-
`sion of communication control program, when the pro-
`gram version for the remote station is older than that for
`the local station.
`7. A communication control apparatus as set forth in
`claim 6, wherein said controller is of a type which sends
`an acknowledgementsignal whenit receives a packet.
`8. A communication control apparatus as set forth in
`claim 7, wherein said storage unit is of a type which
`stores an information message that the communication
`control program ofthe local station is of an old version,
`a request message for transferring communication con-
`trol program of a newer version and the acknowledge-
`ment message for receipt of transferred communication
`control program.
`*
`.
`2
`=
`.
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`Apple v. PMC
`IPR2016-01520
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`PMC Exhibit 2120
`Apple v. PMC
`IPR2016-01520
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