A Method for Data Communication
The invention relates to a method for achieving communication connection between a first computer and a second computer in a network.
A great many computers to-day are connected to the Internet. Many of these computers, particularly those employed in large companies and institutions, are permanently connected to the net. These computers may have a permanent node address, a so-called IP address, which uniquely identifies them on the net.
On the other hand, there are a great many computers without such a permanent connection, where instead connection to the net is established on a temporary basis. Such a connection is usually established by connecting the computer to another computer belonging to a so-called Internet Service Provider (ISP) via a telephone line and a modem, an ISDN line or the like. ISP assigns a temporary IP address to the computer for the duration of the connection. There is a need to gain access from a first computer connected to the net to data and applications in a second computer without permanent connection to the net. For example, it will be of interest to a person at a place of work using a first computer, which is connected to the net, to gain access to data and applications on a computer which is located at another geographical location, for example at the home of the person concerned, based on a temporary connection to the net, for example via a dial-up connection.
Several solutions are known in the prior art which enable a first computer to activate and control a second, remotely located computer, in order thereafter to establish a communication between the first and the second computer. A solution of this kind is disclosed in US-5 892 432. The publication describes a system where a user of a first computer employs a pager message to activate a second computer. In response to this message the second computer can establish communication with the first computer via a modem and a dial-up connection. A similar, prior art solution is disclosed in US-5 337 044.
A disadvantage of the said, prior art solutions is that they are limited to communication where use is made of connection by means of circuit-switched communication (for example a dial-up analog line) between the first and the
second computer. The known solutions have no capability of establishing a connection between the first and the second computer based on Internet technology by means of the TCP/IP protocol. A possible solution would be to couple up a line directly from an Internet Service Provider (ISP) to the second computer concerned. However, this would mean that ISP would incur the communication costs. This represents an organisational and technical barrier.
Thus the known solutions do not provide access to applications and data in the second computer from the first computer, and in particular they do not permit the first computer to be an arbitrary computer, located anywhere in the world, provided that the first computer is linked to a network, particularly the Internet.
An object of the present invention is to provide a method of the type mentioned in the introduction, which is not encumbered by the above- mentioned drawbacks. This object is achieved according to the invention by a method as indicated in the introductory part of the following claim 1 , by means of the features set forth in the characterising part of the claim.
The object is also achieved according to the invention by a method as indicated in the introductory part of the following claim 8, by means of the features set forth in the characterising part of the claim.
Other objects and advantages are achieved by means of the features set forth in the dependent claims.
The invention will be described in more detail by means of an embodiment with reference to the drawings, in which: fig. 1 is a block diagram of a system where a method according to the invention is employed, fig. 2 is a simplified block diagram of a system where the steps in a preferred embodiment of the method are illustrated, fig. 3 is a simplified block diagram of a system where the steps in an alternative embodiment of the method are illustrated.
In the system illustrated in figure 1 a method is employed according to the invention for achieving a communication connection between a first computer
1 1 and a second computer 21 in a network 1. For implementation of the method a third computer 31 is employed which is connected to the network.
The system comprises a network 1 which may comprise a number of nodes in the form of computers or local subnetworks. The network 1 is preferably represented by the Internet, where each node in the network has to be assigned its unique Internet protocol address (IP address) in order to be operative in the network.
Alternatively, the network 1 may be a local network based on TCP/IP protocol, or another type of network where each individual node has to be assigned its unique address in the network in order to be operative in the network.
A first computer 1 1 is arranged to achieve connection with the network 1 by means of a first communication device 12.
The connection between the first computer 1 1 and the network 1 by means of the communication device 12 may be of a permanent or temporary type. The computer 1 1 may be connected to the network 1 either as an independent node in the network or as a node in a local subnetwork (not shown).
The communication device 12 is arranged to provide communication between the first computer 11 and the network 1 , including providing the computer 1 1 with a unique address in the network. This node may be assigned by an Internet Service Provider (ISP) or by the said local network.
The first communication device 12 may comprise a fast, permanent connection to the network 1 , directly or via a local network to which the first computer is connected. In this case the communication device may provide the first computer 1 1 with a permanent IP address, thereby ensuring that the first computer is an operative node in the network.
Alternatively, the first communication device 12 may comprise a modem or an ISDN unit, which via a telephone line or an ISDN line respectively can link the first computer 1 1 to an Internet Service Provider (ISP), which can provide the computer 11 with a temporary IP address, thereby ensuring that it becomes an operative node in the network.
The first computer 1 1 and the first communication device 12 may alternatively together be composed of a mobile communication unit which in a known per
se manner has wireless access to the Internet, for example via a WAP protocol (Wireless Applications Protocol).
The first computer 1 1 is arranged to run a program which gives access to a specific application which is run on a third computer 31 in the network. The program is preferably an Internet browser which gives access to the World Wide Web. If the first computer 1 1 is comprised of a mobile communication unit, the program may be a WAP browser program. The browser program has access to an identification or address for the third computer 31 by means of a host computer identifier which may be linked to the third computer's IP address.
A second computer 21 is arranged to achieve a temporary connection with the network 1 by means of a second communication device 22.
The second communication device may comprise a modem or an ISDN unit, which via a telephone line or an ISDN line respectively can be linked to an Internet Service Provider (ISP), which can provide the second computer with a dynamically allocated, temporary IP address, thereby ensuring that the second computer becomes an operative node in the network.
The second computer 21 is further provided with a control device 41 , which by means of a fifth communication device 43 is arranged to receive a control signal 46 from a communication channel 45, and to initiate the establishment of the temporary connection between the second computer and the network in response to the control signal 46.
The communication channel 45 can at least provide one-way communication, with the fifth communication device 45 as receiver. Alternatively, the communication channel can be employed for two-way communication, with half or full duplex. In this case the fifth communication device 43 is arranged for two-way communication, whereby it can also transmit signals via the communication channel 45.
The communication channel 45 is preferably radio-based, and more specifically based on local radio communication, such as Pocsag (paging), RDS or GSM. In this case the control signal 46 is a message adapted to the specifications of the chosen communication system concerned. For example, the control signal 46 may be an SMS message if the communication channel 45 is based on GSM.
Alternatively, the communication channel 45 may comprise an analog or digital telephone line. In this case the control signal may be an analogously encoded signal, e.g. by means of Frequency Shift Keying (FSK) transferred via the telephone line, or a ringing signal which can be detected on the telephone line. If the communication channel comprises a digital line such as an ISDN line, side channels to the ISDN line may be employed for the control signal.
The information in the control signal must at least comprise information indicating that the second computer 21 has to execute an initiation process. In addition, the information may comprise inter alia identity codes for a user, information on the IP address of the first computer 11, and perhaps also of the third computer 31, and information on log-on times.
In a preferred embodiment the control device 41 is arranged to control the power supply to the second computer 21. In particular the control device 41 is arranged to start up the second computer 21 by connecting the power supply thereto in response to the received control signal from the communication channel.
In the latter case the control device 41 particularly may also be arranged to first disconnect the power supply for a period of time, in order to ensure that the second computer 21 is switched off first before the power supply is connected. This applies if the third computer 31 has no prior information on the condition of the control device 41 and thereby the second computer 21, and particularly if the communication via the communication channel 45 is a oneway communication. After start-up the second computer 21 is arranged to run a program which initiates a temporary connection to the network 1 , especially to the Internet. This is achieved by the operative system of the second computer being configured to start a server program which is configured to establish a contact with an Internet Service Provider (ISP) on start-up, in order thereby to be assigned a temporary IP address, and furthermore to make contact with the third computer 31. The server program may alternatively be a browser program which is configured in a similar manner.
Essential to the invention is the third computer 31, which is also connected to the network 1 through a third communication device 32. The third computer 31 runs a program which provides a special service, designated OOW
("OnOffWeb"), for linking a browser which is run on the first computer with a server program which is run on the second computer, where it provides the browser with the dynamically allocated IP address of the second computer.
The third communication device 32 is composed of equipment and programs for bringing the third computer 31 into connection with the network 1 , and for making the service OOW available from arbitrary browsers on arbitrary computers in the network 1, including from the first computer 1 1.
The third computer 31 may be one of two or more computers which run the same service, and which can be accessed from other computers in the network 1 by means of a common host computer identifier, linked to a number of different IP addresses.
The third computer 3 1 is further connected to a fourth communication device 33, which is arranged to at least transmit control signals 46 via the communication channel 45, where the signals and the channel are preferably based on radio communication such as Pocsag, RDS or GSM, or based on an analog or digital telephone line, as mentioned above. The fourth communication device 33 may alternatively be two-way, whereby it can also receive signals via the in this case two-way communication channel 45.
In a preferred embodiment of the method according to the invention the third computer 31 performs the steps illustrated in figure 2. In figure 2, for the sake of simplicity, the communication devices 12, 22, 32, 33, 43 are not illustrated.
In a first step, indicated by 101 , the third computer 31 receives from the network a request from the first computer 1 1 for the establishment of the communication connection. In practice this is carried out by a user of the first computer 1 1 , which by means of the first browser has gained access to the service OOW which is run on the third computer, sending such a request for the establishment of the communication connection.
In response to this request, indicated by 102, the third computer 31 transmits a control signal 46 to the control device 41 via the communication channel 45.
In order to implement this transfer, the third computer employs the fourth, radio or telephone line-based communication device 33 mentioned above.
In the step indicated by 104 the third computer 31 then receives data from the second computer 21 via the network 1. This is achieved by the request for the establishment of the communication connection being received by the second computer via the control device 41, and by the second computer 21, in response to receiving this signal, having been started up, and subsequently started the execution of a server program which on start-up initiates a temporary connection to the network 1, especially the Internet, as explained above. On connection, the second computer 21 is assigned a dynamically allocated IP address, which temporarily, during the initiated Internet session, uniquely identifies the second computer 21 in the network.
The data received by the third computer 31 from the second computer 21 comprises the dynamically allocated IP address which the second computer 21 has been assigned for the Internet session concerned.
The third computer 31 furthermore passes the said data through the network to the first computer 11.
When the first computer 1 1 receives the said data, especially the dynamically allocated IP address for the second computer 21, these data are used to establish the connection between the first 1 1 and the second 21 computer through the network 1. If so desired, the IP address for the first computer 1 1 may also be transferred to the second computer 21 through the network 1. In this case the second computer 21 does not need to make contact with the third computer 31 , but it may contact the first computer 1 1 directly by means of the transferred IP address. After the necessary data associated with the first and/or the second computer's addresses in the network have been exchanged, the computer 31 no longer needs to participate in the communication between the first computer 1 1 and the second computer 21.
An alternative embodiment of the method is illustrated in fig. 3. In figure 3 as in figure 2, for the sake of simplicity the communication devices 12, 22, 32, 33, 43 are not illustrated.
In a first step, indicated by 201, the third computer 31 receives from the network a request from the first computer 1 1 for the establishment of the communication connection. The third computer 31 hereby receives address
data associated with the first computer's address in the network, particularly its IP address.
In the same way as in the preferred embodiment, this takes place by a user of the first computer 1 1, which by means of the first browser has gained access to the service OOW which is run on the third computer, sending such a request for the establishment of the communication connection, together with the said address data.
In response to this request, indicated by 102, the third computer 31 transmits a control signal 46 to the control device 41 via the communication channel 45, corresponding to that described above. In this case the control signal comprises the said address data associated with the address of the first computer 1 1.
When the request and the said address data have been received by the second computer 21 via the control device 41, the second computer 21 starts an initiation process, which as in the preferred embodiment may comprise initiating a temporary link with the network 1, especially the Internet, or starting up the second computer 21 in advance, and subsequently starting the execution of a server program as explained above.
The said address data for the first computer's 1 1 address in the network are then used to establish a connection between the first 1 1 and the second 21 computer through the network 1.
The invention is described above by means of examples. Those skilled in the art, however, will appreciate that many modifications and variations of the present invention are possible within the scope of the invention, as it is defined in the following claims.