FR2778297A1 - Packet mode two network transmission method - Google Patents

Abstract

The adaptation bridge allows the internet to be accessed from another transmission network.

Description

Data transmission method

between two packet networks.

  Applications implementing data transmissions from terminals of the cellular radio telephone type such as those of the GSM network are developing rapidly. Among these, those which consist in accessing a computer network of the INTERNET type, or in private INTRANET networks, with IP type protocols like those used for accesses to the INTERNET, are particularly carriers of to come up. These applications make it possible to offer users many services such as: messaging, interactive consultation of private or public information services, file transfers or

  images, teleaction or remote management, and others.

  A mode of access to the INTERNET from such terminals consists in establishing, with an ISP access point to the INTERNET (ISP: access service provider: "Internet Service Provider"), a connection of the " circuit mode data transfer "which reserves, in an access network, such as the switched telephone network, PSTN, a communication channel or resource for the duration of the connection. The conventional Internet access protocols are then implemented, for example: SLIP or PPP, IP, TCP or UDP or other. They offer in particular the addressing mechanisms necessary for the routing of information packets between the terminal and its correspondent on the INTERNET. This circuit mode access mode has the advantage of offering a transfer time of minimum and guaranteed duration on the access network, since the communication channel is entirely reserved for the terminal. It is well suited to services requiring the maximum bandwidth available on the access network, such as the transfer of large files or images, and / or requiring the minimum round-trip response time on the network. access, such as interactive applications with multiple successive interrogations. The major drawback of this circuit mode lies in the fact that applications having low requirements on response times and those where interrogations are infrequent use the same means of supplying bandwidth,

  while these will remain unused a large percentage of the time.

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  Another mode of access to the INTERNET from such terminals consists in using the Short Message Services, or possibly the USSD (Unstructured Supplementary Service Data), offering a time lower transfer rate than SMS. This mode has the advantage of using the access network in packet mode, or datagram, which is more consistent with the transport mechanisms of the INTERNET network. The communication resource in the access network is used in a more optimized way, because it is temporarily released for other terminals when there is no information to be transmitted. It is therefore preferable for applications with low time requirements.

  of response and for those where the interrogations are infrequent.

  As, in packet mode, the same channel is used in timeshare by various communications, each packet includes, in addition to the useful data to be transmitted, the address of its sender and the address of the recipient and possibly other data of service as per

example a serial number.

  The service data being of fixed volume, we associate with it a volume of useful data large enough so that the total packet is essentially composed of useful data, otherwise the interest of the packet mode

would be lost.

  However, SMS Short Message Service packets only allow the transmission of small packets and therefore do not allow the rapid transmission of a large volume of data, coming from

example of an INTERNET server.

  Therefore, access in packet mode to the INTERNET seemed a priori excluded. More precisely, if each INTERNET packet of useful data and signaling was transported, in the limited field reserved for the useful data of an SMS packet, INTERNET signaling would not leave

  too little space in this field for INTERNET payloads.

  The alternative of transporting the INTERNET package in the field

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  signaling of the SMS packet is excluded because it is too large. The present invention aims to propose a good compromise between the constraints set out above. To this end, the invention relates to a method of transmitting data between a first data transmission equipment connected to a first packet transmission network, of the cellular telephone type, and a second transmission equipment connected to a second transmission network. by packets of the INTERNET type, each packet from either of the networks comprising a useful data field and a signaling field, a method characterized by the fact that the two networks are connected by a gateway adaptation of the data and routing control in the two networks and transporting, through the first network, the two packet fields of the second network respectively in

  the two peer packet fields of the first network.

  The proposed solution therefore consists of a functional fusion of the two networks for a unified operation, which has the advantage, compared to the global encapsulation described above, of using the signaling field of the first network for the signals of the two networks. ,

  thus leaving the data field fully available.

  The solution therefore consists, in the case of the GSM network, in allowing each SMS message sent by a terminal to include, in the GSM signaling field, the signals indicating the IP address to which, on the INTERNET, the packet containing the information

contained in this SMS message.

  The invention will be better understood using the following description of a

  preferred embodiment of the method of the invention, with reference to the appended drawing, in which - FIG. 1 illustrates a connection of networks according to the prior art, - FIG. 2 illustrates a connection of networks according to the invention, and

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  - Figure 3 shows GSM packet transport packets

INTERNET.

  In FIG. 1, illustrating the prior art, the equipment 1, here a terminal, is connected to the packet data transmission network 2, here the GSM network, which itself is connected to a service provider. access 9 (ISP) through the PSTN 8 switched telephone network, connected to INTERNET 6

  to which an equipment 7 is connected, here an information data server.

  Below the network diagram are represented four logical layers 11 to 14 for the transmission of data in the GSM: layer 11: circuit mode (level 1 of OSI (Open Systems Interconnection), layer 12: SLIP or PPP (level 2), layer 13: IP routing (INTERNET address) (level 3), layer 14: TCP or UDP or others (level 4) of transport protocol. Layers 13 and 14 become the

  layers 23 and 24 as they pass through the INTERNET 6.

  FIG. 2, illustrating the invention, differs from FIG. 1 by the fact that the PSTN 8, for access in circuit mode to the INTERNET 6 (operating in packet mode), has disappeared and that the access provider ( ISP) to INTERNET is replaced by the gateway 3, 4, 5 comprising circuits 4 for adapting the transmitted data, such as the format, and routing circuits 3 and 5 for respectively the transmissions in the GSM network 2 and the INTERNET 6. Circuit 4 is in fact a Service Center for

Short Messages, SMS-C.

  The IP address of the server 7, called by the terminal 1, is here in layer 33 in a packet message, which, in this example, is of the SMS short message type, suitable for the GSM network but which, in general , East

any type of package.

  The layer 33, homologous to the layer 13, corresponds to a signaling layer (OSI level 3) and there is no longer, in FIG. 2, the equivalent of the lower layers 11 and 12: all the signaling is transmitted in a

  signaling channel 17 of the packet and not in the useful band 16 (fig. 3).

  Layer 34 corresponds to layer 14.

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  Layers 43 and 44 in INTERNET 6 correspond respectively

at layers 33 and 34.

  In addition to the address allowing routing in the "target" network 6, point-to-point connection elements can also be transmitted in the same way.

PPP point (12).

  It is understood that, the two networks 2 and 6 having the same packet transmission property, the INTERNET 6 of the example can likewise

send to the GSM network 2.

  The upper layer information (TCP, UDP, or other) is

  contained in the "user data" part 16 transported by SMS.

  The new information elements (IEs) contain all the data necessary for the formatting by SMS-C 4 and router 5 of IP INTERNET packets. They include, in particular, the destination address of the

  IP packet 20 and the original address of the packet.

  The INTERNET signaling can be kept in whole or in part as it is, with an adaptation of possible form, by extending the SMS or USSD signaling protocol by new code words IE (Element of Information) representing the INTERNET signals. It is therefore a superset of the conventional GSM protocol, making it possible for example to convey INTERNET address data via circuits 4 and routing circuits 3 and 5. We therefore add, to the signaling of the packets of the GSM network 2, code words representing

  INTERNET network signals 6.

  The classic SMS protocol is therefore extended accordingly according to INTERNET signaling, to take into account in particular

IP addressing.

  The gateway 3, 4, 5, and in particular the circuits 3 and 4, is likewise provided for processing the SMS protocol thus extended and in particular processing

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  SLIP (Serial Line INTERNET Protocol) and / or PPP (Point-to-Point Protocol) signals. The gateway 3, 4, 5 also ensures the formatting of the packets in both directions, to extract and reconstitute, in a single packet 20, the fields 18 and 19 coming from the GMS network 2, and transmit it on the INTERNET 6 by router 5. The reverse operation, of separation of the fields 18, 19, takes place for the packets 20 coming from the INTERNET 6. The terminal 1 performs the operations reverse from those of the gateway 3, 4, 5 and, thus, the GSM 2 network is transparent to

INTERNET packets 20.

  These destination and origin addresses and all or part of the signaling can, conversely, possibly be represented for their transport by IEs already defined by the GSM protocol but which are useless, not applicable, in access access applications. 'INTERNET (by

  example the telephone numbers of the sender and receiver of the SMS).

  In any case, IEs useless to INTERNET applications are not used here. This avoids any overload of the GSM 17 signaling field. FIG. 3 illustrates the way of transporting each INTERNET packet to

through the GSM network 2.

  A packet 15 in GSM format includes field 16 of useful data, up to 140 bytes, and field 17, more limited, of IE signaling data or IE Information Elements. The packet 20 in INTERNET format likewise comprises a field 18 of useful data and a field 19 of signaling data. Here, the size of the field 18 is limited to that of the homologous field 16. Similarly, the data of

  signaling in field 19 can be accommodated in field 17.

  For the transport of packet 20 INTERNET through the GSM network 2, the two fields 18 and 19 of packet 20 are housed in the

  two homologous fields 16 and 17 of packet 15 in GSM format.

  Thus, the GSM 16 field remains reserved for useful data and their offer

  therefore an undegraded bandwidth.

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Claims (5)

  1.- Data transmission method between a first data transmission equipment (1) connected to a first packet transmission network (2), of the cellular telephone type, and a second transmission equipment (7) connected to a second packet data transmission network (6), of the INTERNET type, each packet of either of the networks (2, 6) comprising a useful data field (16, 18) and a data field signaling (17, 19), method characterized by the fact that the two networks (2, 6) are connected by a gateway (3, 4, 5) for adapting the data and routing control in the two networks (2 , 6) and transporting, through the first network (2), the two packet fields (18, 19) of the second network (6) respectively in the two fields of   peer packet (16, 17) of the first network (2).   2. The method of claim 1, in which code words of the first network packets (2) are added.   representing signals from the second network (6).   3.- Method according to one of claims 1 and 2, wherein it is reused,   to transport the signals (19) of the packets of the second network (6) into those of the first network (2), code words of the latter without   utility for connections between two such networks (2, 6).   4.- Method according to one of claims 1 to 3, wherein one transmits   the data between a first GSM network (2) and a second INTERNET network (6), by housing INTERNET addresses in the field of signaling of SMS packets.   5.- Method according to one of claims 1 to 4, wherein, at the level   from the gateway (4), packets from the first network (2) are extracted, the two packet fields from the second network (18, 19) before sending them, in the second network (6), in the form of '' a package (20) of second network (6).