Method of and apparatus for connecting a wireless lan network to a wired lan network

The present invention relates to a method and apparatus for transferring data between nodes in a network, in particular wireless nodes or wireless LANs and wired LANs.

Known local area computer networks (LANs) consist of interconnected nodes using physical telecommunications intermediaries, for example coaxial cables, wired twisted pairs or optical fibers. There are also known wireless LANs whose nodes are not connected by some material intermediary. These wireless LANs connect via infrared (IR), radio, or other signals. The advantage of wireless LANs is that no cables are needed. This feature is useful especially for mobile nodes, such as hand-held (laptop) or notebook (note-book) computers, personal assistance equipment (PDA) and the like. When equipped with a suitable wireless adapter, which includes a transceiver and control card, such as a wireless IR adapter, mobile nodes can move while being connected to the network, as long as they do not go out of range.

A known way of implementing a wireless LAN is similar to a cellular network system. In this method, the wireless nodes do not communicate directly with each other, but instead send all signals to the central base station, which then sends them to the destination node.

However, in some situations it is beneficial if each of the wireless nodes has the ability to connect to other nodes, as in most wired LANs. In a wireless LAN this is enabled by the wireless adapter and control software transmitting data packets that are heard by all nodes in range. This allows packets to be transmitted that are received but ignored by all nodes except the one or more to which they are addressed. This ensures parallel operation of packet delivery systems with such a wired LAN protocol as Ethernet. Thus, with such a wireless LAN network can be operated upper-level system operating software, based on such a packet delivery system as

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NETWARE from Novell Corporation. This wireless LAN is called a peer wireless LAN.

An important physical feature of equivalent wireless LANs is that it is difficult to use it to set up a reliable network comparable to a wired LAN. In a wired LAN, each network node is physically attached, and therefore can have access to all network traffic. In the case of wireless LANs, this is often not the case. Each node communicates with the other nodes by means of an electromagnetic signal whose range is limited. Each node has a certain coverage area, which is limited by the signal type, its strength, obstacles in the coverage area, etc. In the case of wireless LANs, it cannot be guaranteed that every network node that is presumably part of the wireless network itself can listen to all messages in the network traffic. For example, if nodes A, B and C are connected to the same wireless network, then node A may be able to hear data sent by node B and not hear data from node C. In this case, node C is the "hidden node" for the node A. If node C can hear node B but cannot hear node A, then node A is a hidden node for node C.

To ensure proper operation, it is desirable that the wireless LAN also be able to connect to a wired LAN. For wireless networks using the base station policy, this base may provide attachment. However, there is a need for a system that provides inter-network services between peer-to-peer wireless LANs and a wired LAN.

There are several problems with wireless sicciaLAN that complicate the implementation of a simple bridge device for connecting a wireless LAN to a wired LAN. The primary function of such a device is the retransmission of eavesdropped wireless LAN data that is intended for a wired node in a wired LAN, and vice versa. Depending on the wireless intermediary chosen, each device would normally have a limited range. To ensure adequate coverage, multiple devices must be used, each with a certain overlap. This would normally duplicate the messages received by the nodes in areas of overlapping coverage, and in the case of wired LANs also messages outgoing from such nodes.

It should be clarified that the term "interconnection services" refers to services that enable systems to communicate that would not otherwise be possible. Typical inter-network services include forwarding messages from one wireless node to another, retransmitting messages from the wired LAN to the wireless node, and retransmitting messages from the wireless node to the wired LAN. An inter-network node that provides such inter-network services is called an AP. An AP is a physical device that fully includes a wired network adapter and a wireless network adapter to provide inter-network services.

The physical area in which the wireless node must be located to be within range of the AP is called the base service area (BSA). If the wireless node is within the BSA of a particular AP, the wireless node will be able to receive transmissions transmitted by that AP.

Each wireless node also has a limited area in which it can connect. This area is called the dynamic service area (DSA) of the wireless node. Other nodes within the DSA area of ​​the wireless node will usually be able to receive transmissions from the wireless node.

If the wireless nodes use the same adapter as the AP, then if all other parameters are equal, the wireless nodes will have the same coverage as the AP. However, there may be differences between the AP BSA range and the DSA area of ​​the wireless node. First, wireless nodes are usually mobile nodes. Thus, their range may vary depending on the effects on the signals

178 035 obstacles to their propagation. Also because access points as physically attached to the wired LAN are also attached to the power supply. Thus, the transmitter used at the AP may be more powerful than the battery-operated transmitters of the wireless nodes. If this is the case, the BSA area coverage for the access point will usually be greater than the DSA area coverage for the wireless node.

A distinction has been made between the BSA area of ​​the AP and the DSA area of ​​the wireless node, even if the two areas are the same. One wireless node is referred to as "listening" to the other wireless node if it is within the DSA area of ​​the other node, so that it can receive signals sent by the other node. Similarly, a wireless node may "listen" to an AP if it is within the BSA of that node. A "multilateral" message is a versatile, broadcast message broadcast by a wired or wireless node that is addressed to other nodes with the same distinctive group address. All other wired or wireless nodes ignore this message.

Known from European Patent Application No. 0 483 544 is a method of telecommunication, in which communication between mobile objects must be through a controller. Moving objects are notified only by the controller. It is a "master-slave" type system in which the controller mediates all communication between moving objects. The driver calls to report the presence of other systems.

PCT Patent Application No. WO 92/19059 describes another "master-slave" type system in which communication between moving objects must be conducted through a controller. He calls other existing stations to report, and the calling station hears the response.

The essence of the method of transferring data between nodes in a network according to the invention, in which data from one node is wirelessly transmitted to other nodes in the network and data from such nodes is wirelessly received, and with each message transmitted wirelessly from the node identification information is transmitted which identifies this node, and the data suitable for sending the assignment request to the interconnection node is that the data received wirelessly is controlled, identification information is separated from the received data, which identifies other information on the basis of which it is determined whether each other node whose data was received is identified in such information as an interconnection node and the identification information indicating whether this other node has been identified as an interconnection is remembered, after which access to the stored identification information is obtained each time, when a node needs to send data to a specific node other than the inter-network node to which it is assigned, and the data is redirected to the assigned inter-network node for further transmission, if the identification data for that particular node is not in the stored identification information.

It is preferred that the identification information for other nodes that have been identified as interconnection nodes is stored in the first table and the identification information for nodes that are not identified as interconnection nodes is stored in the second table.

It is preferred that it is determined whether the stored identification information is information for a node that is not an inter-network node, for one inter-network node or for more than one inter-network node.

It is preferred that if the identification information is information for one and only one inter-network node, then a matching request is suitable for that one inter-network node.

It is preferred that if the stored identification information is information for more than one interconnection node and the first node is not yet assigned to the interconnection node, then one of the interconnection nodes for which the identification information has been stored is selected and suitable for that selected one node interconnection assignment request.

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It is preferred that if one receives confirmation that the one interconnection node has accepted the assignment request, a record is stored indicating that this one interconnection node is assigned to the node.

It is preferred that if confirmation is received that the selected interconnection node has accepted the assignment request, a record is stored indicating that the selected interconnection node is assigned to the node.

It is preferred that the transmissions from the first node to the assigned interconnection node are monitored and the stored record is deleted if the transmission from the node to the interconnection node has not been confirmed by the interconnection node.

It is preferred that the identification information includes the network address of the node to which such information relates.

It is preferred that assignment requests from other nodes are accepted and a list of all other nodes that have been assigned to the first node is stored by sending the assignment request that has been received by the first node.

It is preferred that a message is transmitted to other interconnection nodes via a wired network each time the first node receives an assignment request from another node, with other interconnection nodes being notified by means of that message that the first node has been assigned to such another node .

It is preferred that the data in the wired network is monitored and data that is addressed to any node in the list is selected, after which the data is transmitted wirelessly at the address of the node in the list.

It is beneficial that the data is checked in relation to the message addressed to this node for their further forwarding by that node to a specific other node, it is determined whether this particular other node is in the list, and the message intended for re-sending is sent a specific other node, if that particular other wireless node is on the list, and a message is intended to be resent to the wired network at the address of a particular other node if that particular other node is not on the list.

It is beneficial that the data is checked when all messages are received, including those that are not directed to the first node, a list is kept of all other nodes from which such messages have been received within a specified period of time, and it is then determined whether each new received the message has arrived from a listed node, and a reply is given when the message arrives from a non-listed node, and the node is entered in the list.

It is preferred that the identification information is given to the first node each time the first node receives a message from a node that is not listed.

It is preferred that the data is checked with respect to the message directed to the node for its further forwarding by that node to a specific other node, and the message to be re-sent to a specific other node is directed.

The essence of the device for transferring data between nodes in a network according to the invention comprising a communication network with a plurality of nodes, each comprising a wireless network adapter for transmitting data over a wireless communication network from one node to other nodes in a network and for receiving data over a wireless network communications from these nodes, and a transmitter to transmit, along with each data message sent by the node via a wireless network adapter, identification information for this node and for transmitting data intended to send an assignment request to an interconnection node, it is that it includes a functionally connected controller to control data received by the wireless network adapter, for extracting from the identification information information identifying other network nodes whose data are received, and extract identification information determining whether any other node whose data was received, is identified in such information as a cross-network node, re-storage of identification information indicating whether this other node has been identified as a cross-network node, memory access to the circuit each time the node needs to send data to a specific other node other than the inter-network node , to which it is assigned, and the redirection circuit of this data to the assigned muscle mine node, for further forwarding if the identification data for that particular node is not in memory.

It is preferred that the inter-network node contains a memory for storing information identifying it as a nervous network node.

It is preferred that the nlemlice node contains a first table of identification information for other nodes that have been identified as interconnection nodes, and a second table of identification information for nodes that have not been identified as intercity nodes.

It is preferred that the non-interstitial node includes a circuit for determining whether the memory contains stored identification information for a non-pertinent node, one inter-network node or more than one inter-network node

It is preferred that it includes a transmitter for transmitting an association request to one interconnection node if the determination circuit finds that the memory contains stored information ideation for one and only one interconnection node.

It is beneficial that after the circuit determines that the memory contains the stored identification information of more than one mesenteric node that is not yet assigned to the inter-network node, it selects a user from the interstitial nodes for which the memory contains the stored identification information, and triggers the transmission, through the transmitter, requests to assign to this selected one miller node.

It is preferred that after the circuit receives the determination of the confirmation by the wireless network adapter that this one interconnection node has accepted the assignment request, it enters the memory indicating that this one interconnection node is assigned to the node of which the determination circuit forms part.

It is preferred that after the circuit receives the determination of the confirmation by the wireless network adapter that the selected interconnection node has accepted the assignment request, it enters the position indicating that the selected interconnection node is assigned to the node of which the determination circuit forms part.

It is preferred that the determination circuit controls the transmission from the node of which it is a part to the interconnection node which is shown in memory as assigned to the node of which it is part and deletes the assignment record in memory if the transmission from the node of which it forms part to interconnection node is not confirmed by interconnection node.

It is preferred that the identification information includes the network address of the node to which such information relates.

It is preferred that the interconnection node has a circuit for receiving assignment requests from other nodes, and a second memory for storing a list of all other nodes that have been assigned to that node by giving the assignment request that has been received by the node.

It is preferred that the interstitial node includes a transmitter for transmitting a message to other interstitial nodes via a wired network each time the node receives an assignment request from another node, wherein the message notifies the other interstitial node that this node has been assigned to such another node.

It is preferred that the inter-network node includes a second data controller in the wired network, and a selector for selecting data that is addressed to any node in the list, and wirelessly transmitting this data by the wireless adapter at the node address in the list.

It is preferred that the inter-network node includes a third controller for controlling the wireless network adapter with respect to messages routed to that node for their subsequent forwarding by that node to a specific other node, a circuit determining whether this particular other node is listed, and a routing circuit for moving the adapter

178 035 the wireless network to resend the message to a specific other node if that particular other node is in the list, and to switch the wired network adapter to resend the message in the wired network to the address of a particular other node if that particular other node is not in the list.

It is preferred that the inter-network node includes a fourth controller for controlling the wireless network adapter with respect to the receipt of any messages, including those not directed to that node, a third memory for remembering a list of all other nodes from which the message has been received in a given interval time, a comparator to determine if each of the new messages received came from a node in the list, and a node entry circuit when the message arrives from an unlisted node.

It is preferred that the startup circuit introduces, via the wireless adapter, identification information that identifies the node each time a node receives a message from a node that is not listed.

It is preferred that the inter-network node includes a third controller for controlling the wireless adapter with respect to the message directed to that node for its further forwarding by that node to a specific other node, and a circuit for resetting the wireless adapter to re-broadcast the message to a specific other node.

The invention in the embodiments is illustrated in the drawing, in which Fig. 1 schematically shows the structure of wireless nodes around a wired LAN, with two APs as interconnection nodes and with a dashed line represented by the DSA area of ​​each wireless node, Fig. 2 schematically the same structure as in Fig. 1, but showing the BSA area of ​​each AP, Fig. 3 - schematically, for the same configuration as in Fig. 2, using the inventive solution to forward a message from node B to node A, from node A to node D and from node A to node X, Fig. 4 - schematically, for the same configuration as in Fig. 2, wandering of node A from BSA area of ​​AP1 to BSA area of ​​AP2, Fig. 5 - block diagram of a non-network node and Fig. 6 - block diagram of an inter-network node.

Both Figure 1 and Figure 2 schematically show the structure of the wireless nodes A, B, C, D and E, the wired LAN 50, the wired node X and the points AP, API and AP2. Each AP is a physical device containing a wired network adapter. Every AP understands the protocols of both wired LAN and wireless LAN.

Using standard terminology according to ISO / CCITT OSI, the AP behaves like a layer 2 layer of a data link unit that bridges a wireless LAN with a wired LAN. It transmits the data traffic from the wireless LAN to the wired LAN in such a way that the data traffic appears in the wired LAN nodes as outgoing from the wired LAN nodes. It also transmits data traffic from the wired LAN to the wireless LAN in such a way that this data traffic appears in the wireless LAN nodes as outgoing from the wireless nodes in the wireless LAN. Thus, each AP acts as a transparent bridge to control broker access (MAC) that connects infrared IR nodes to a wired LAN network.

In the examples shown in the figure, the same wireless adapter is used for both APs and wireless nodes. Therefore, the range of AP BSAs, apart from the obstacles, will be the same as the range of DSA for these wireless nodes. The AP, being physically connected to the power supply, should keep the transmitter more powerful with extended BSA coverage.

The structures shown in Fig. 1 and Fig. 2 are identical, except that Fig. 1 shows the DSA area coverage of wireless nodes, while Fig. 2 shows the BSA area coverage of APs. In Fig. 1, wireless node A has a range defined by an area

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AP, he can instruct this AP to submit a request to liquidate the subordination to the previous AP.

After receiving an unassignment data packet from the new AP, the previous AP deletes the wireless node address from its BSS.

In addition, each AP may also maintain a separate BSA table, similar to the DSA table maintained by each wireless node, for the BSA, a list of addresses of all wireless nodes inside its BSA, regardless of whether they are assigned to it.

The wireless node only accepts data packets transmitted by the AP to which it is assigned, and discards all data packets transmitted by other APs. Of course, he accepts data packets that are intended for him and that were sent by other wireless nodes.

As stated, each of these wireless nodes makes a choice of which APs will be assigned to the wireless nodes. Thus, each AP accepts all data packets transmitted by any wireless node. If the AP receives a data packet addressed to it by another wireless node that is not assigned to it, the AP deems that packet as inherently a mapping request. Adds the address of this wireless node to its BSS table and forwards the packet to the wired LAN.

If the wireless node does not correctly transmit the data packet to the assigned AP, i.e. the AP does not acknowledge receipt of the data packet, the wireless node considers its connection to the AP as broken. Clears his assignment to this AP then he browses his table to see if another AP is available. If there is one such AP, then an attempt will be made to assign to that AP. If there is more than one AP, the AP will select the last heard AP. Similarly, if the AP does not correctly send the data packet to the wireless node assigned to it, it considers its connection with the wireless node broken, and deletes that node in the table.

At work, when the wireless node, i.e. the sender, is ready to send a data packet to another wireless node, it first checks to see if the network node address for the destination node is in its DSA table. If so, it assumes that the destination node is another wireless node within the DSA area of ​​the sending node. Therefore, the sending node sends the data packet to another wireless node directly. If the wireless node is not in the DSA table, the transmitting node sends this data packet to the assigned AP and asks the AP to help deliver the data packet to the destination node.

After receiving the data packet, the AP compares the destination of the data packet with its own BSS, i.e. it checks whether the destination node is also assigned to this AP, and the AP transmits the data packet to the destination node directly via a wired LAN. If the destination node is a wired node, it receives the data packet directly. If the destination node is in a different wireless LAN that is connected to the same wired LAN through a different AP, i.e. the destination node is a wireless node assigned to a different AP, then that other AP will forward the data packet to that destination node .

Figure 3 shows three examples of using the solution according to the invention. Suppose node A of the network just entered the BSA of AP1. We assume that node A has not been previously assigned to any AP. When he hears AP1 recognition signal or hears certain data in motion from AP1 to node B of the wireless network, node A transmits to AP1 a data packet with an assignment request. After the data packet has been successfully transmitted with the assignment request, i.e., the confirmation of the AP1 point is maintained, the node A is deemed to be assigned to the AP1 point. After receiving the correct data packet with the assignment request, AP1 introduces

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DSA 10, wireless node B has a range determined by DSA 20, wireless node C has a range determined by DSA 40, and wireless node E has a range determined by DSA 45.

In a wireless LAN, it cannot be guaranteed that every network node that is part of the same wireless network can receive all network traffic. In Fig. 1, wireless node E may hear network data transmitted by wireless node B, but not through wireless node C, because wireless node E is within DSA 20 of node B, but is outside DSA 30 of node C. case, node C is a node hidden from node E. Similarly, node C is a node hidden from node E because node C is outside the DSA area 45 of node E.

In some situations, it is possible, in the case of an IR wireless node, to receive data transmitted by another wireless node without being able to transmit to that node. For example, the first node could hear network data transmitted by the second node, but the second node would not be able to receive data transmitted by the first node. This situation is called asymmetry.

In order to compensate for possible transmission losses, packet delivery systems usually require the receiving nodes to send special acknowledgment to the sending node, acknowledgment of receipt of each data packet. For example, if wireless node A transmits a packet to wireless node B, then node B sends a packet to node A, acknowledgment of receipt of node N message in the case of packet delivery systems in wired LANs, such acknowledgments are not usually required due to the small level of transmission loss in this kind of intermediary.

In Figure 2, the AP1 BSA area is indicated by a circle 60, while the AP2 area is shown as having a BSA 70 area. Wireless nodes A, B, and E are inside the APA BSA 60 area. Wireless node B is also within BSA 70 of AP2, similar to wireless node D. Wireless node C is not within the reach of any of the access points.

Note that since node B is in range of both APs, the wired LAN will receive unwanted double messages if both AP1 and AP2 retransmit the message from node B to the wired LAN, and similarly, node B will receive unwanted double messages messages, if both AP1 and AP2 retransmit the message from the wired LAN to node B.

In order to avoid such a doubling, a switching mechanism is proposed to ensure that no more than one AP is affected by any particular wireless node by ensuring that each wireless node is "assigned" to no more than one AP.

Each wireless node decides which AP (assuming there are more than one in range) to be assigned to it. In addition, each wireless node determines whether it can broadcast a message directly to its destination node, and asks for the AP to which the message should be delivered if it cannot do it directly. Each AP decides whether to retransmit the data packet from the wired LAN to the wireless node to which the packet is addressed. Each ASP controls the wired LAN data traffic for each data packet that is intended, i.e. addressed, for one of the APs assigned to the wireless nodes. If the AP hears such a data packet in the wired LAN, it accepts the data packet and forwards it to the mobile node.

Each wireless node must consider the other nodes surrounding it so that it can decide if it can transmit to them. Therefore, each wireless node controls wireless traffic, and maintains an address table of all recently heard wireless nodes. This table is called the DSA table. If the node heard another node, then the address of that other node is in the DSA table assuming that it can be transmitted to

178 035 this node. This table represents all of the other nodes with a tracking node inside the DSA area.

In another embodiment, each wireless node relies in the DSA table setup on eavesdropping messages from nearby nodes, including all acknowledgments. Alternatively, each wireless node can broadcast a target signal, which can be eavesdropped automatically by all other nodes within its DSA area.

Each wireless node also controls network traffic by searching for data packets sent by a certain AP. To assist wireless nodes, especially nodes that are actually moving, near their APs, each AP transmits a reconnaissance signal 'at regular intervals, e.g. every 20 seconds, identifying the AP's address in the wireless network. Each wireless node has a separate table, called the AP table, which specifies the addresses of all APs heard. It is advantageous if other information is also stored in such a table, for example which AP was heard recently, most often, the least often, etc. In contrast, this information can be stored as part of the DSA table. It is advantageous if the wireless node can distinguish data packets from APs from packets from other wireless nodes due to the fact that one of the bits in the wireless data packet control field indicates whether the data packet is generated at the AP. It is also possible for each AP to be assigned a unique wireless address with a common prefix for its wireless LAN connection. For example, the network address may be "IRAP001", where IRAP is the common prefix for all AP addresses in a wireless network. This common prefix is ​​not assigned to the desired wireless node other than the AP.

Each AP is assigned a wired network group address for its connections to a wired LAN network. This group address is used to broadcast "multilateral" transmissions. When sending a multilateral message, in the form of a versatile, broadcast message, to an AP group address in a wired LAN, all APs, but only APs, receive this message. All other wired network nodes ignore this message.

When a wireless node eavesdrops on an AP, it introduces the AP to its AP table. The node also determines which of the APs in its table is assigned to it. For example, this may include: assignment, if the board is empty (i.e., the wireless node has just been powered on, or has just been brought into close proximity to the wired LAN), or maintenance of the assignment to the current AP until the AP is lost, or assignment to the AP most audible, etc.

If the procedure indicates that a wireless node should be assigned to an AP, the wireless node will send a data packet to the AP requesting the assignment. If the packet with the assignment request is successfully transmitted to AP, that is, confirmed by this AP. The mapping request contains the wireless node address in the wireless network. It is beneficial if the request also indicates which AP was, if any, previously assigned to it.

Each AP stores a table, called its Basic Service Team Table (BBS), covering all wireless nodes to which it is associated. After successfully receiving any assignment request from the wireless node, the AP enters the network address of that node into its BBS table. The AP can be configured so that if the assignment request indicates that a wireless network node has previously been assigned to another AP, it sends to the previous AP, via wired LAN, an assignment cancellation data packet notifying that AP that the assignment should be unassigned to the wireless node. However, after assigning the wireless node to a new point

178 035 node A to the BSS table. It also sends a de-assignment data packet to the wired LAN, notifying the previously assigned AP that AP1 is currently assigned to node A and that the previous AP should be excluded from the assignment. This can be done by omni-directional broadcasting or by using a packet directed to the AP to which node A is actually assigned.

Suppose node A wants to send a data packet to node X of a wired network. Node A first browses its DSA table to see if Node X is a wireless node within range. Because node X is not in the DSA area corresponding to node A, node A transmits the data packet to point AP1, as shown by arrow 100 in Fig. 3. Next, AP1 browses its BSS table to determine if node X is associated with a wireless node within its BSA. Because node X is not listed in such a list, AP1 in turn retransmits the data packet to the wired LAN, as shown by arrow 105.

Assuming additionally that after receiving the packet, the node X transmits the response data packet to return to node A. The AP1 point controls the wired LAN data traffic and eavesdrops on the data packet intended for the node A which is located in its BSS table. AP1 takes over the data packet and transmits it to node A via a wireless proxy.

Assuming now that both nodes A and B are assigned to point AP1, that is, they are both in the BSS table of point AP1, and that node B wants to send a data packet to node A. Node B checks its DSA area to see if it finds within its range. As can be seen in Fig. 1, node B is not within DSA 10 of node A, and node A is not within DSA 20 of node B. In other words, the nodes are hidden from each other even though they are within the range of AP1. Direct wireless communication between these two nodes is not possible. Therefore, node B transmits the data packet to AP1 asking for help in providing the data packet, as shown by arrow 120 in Fig. 3. AP1 browses its BSS table and determines that node A is assigned to it, then AP1 transmits the data packet via wireless proxy to node A, as shown by arrow 125. Note that although node B is within the BSA of the point AP2, node B is assigned to point AP1, and therefore does not ask for point AP2.

Suppose now that node A wants to send a data packet to node D, which is assigned to AP2. Because node D is not inside the DSA area of ​​node A, node A transmits the packet to AP1, as shown by arrow 130. Because node D is not assigned to AP1, AP1 retransmits the data packet to the wired LAN, as shown by arrow 135. AP2 eavesdrops on this data packet, states that node D is assigned to it, and retransmits the data packet directly to node D, as shown by arrow 140.

Note that node B is inside the BSA area of ​​both AP1 and AP2. If node B has been assigned to AP2 and therefore has not been assigned to AP1, and wireless node A transmits the data packet directly to node B, AP1 does not send the data packet directly to B, but retransmits it via a wired LAN. In this situation, AP2 picks up the data packet and retransmits it to node B (because node B is in the APS BSS table), as is the case with node D.

Figure 4 shows the entry and exit of a roaming wireless node from various BSA areas of APs. When a wireless node moves between BSAs of APs, its assignment to one AP is removed, and it is assigned to another. The data packets sent by the wireless node to the wired LAN are transmitted through different APs, depending on where the wireless node is located and to which AP the wireless node has been assigned. Similarly, data packets intended for a wireless node are transmitted through different APs, depending on where the wireless node is located and to which AP the wireless node has been assigned.

During the node's wandering, it may go out of range of all APs from its AP table. The wireless node is then disconnected from the wired LAN until it enters the range of another AP and assigns itself to that AP. Of course, a wandering node cannot associate with any AP until it finds the presence of such AP, i.e. until it hears or recognition signal or regular transmission. In addition, to reduce the time between the entry of a mobile network node in the BSA area of ​​the AP and the detection of the presence of the AP, each AP may broadcast its recognition signal sooner when it first detects a wireless node. To this end, the AP maintains the BSA table, in addition to the BSS table described above. Alternatively, it combines both boards into an extended BSA board with an additional column stating whether each listed wireless node is assigned to it. If the AP overhears a wireless node that is not listed in its BSA table, that AP generates its reconnaissance signal as planned. The AP detects the presence of a wireless node by eavesdropping on a data packet, usually a comprehensively distributed packet, transmitted by a wireless node. This comprehensive distribution packet is usually generated in response to an upper-layer operating system attempting to determine which additional nodes are in the network. The result of this comprehensively distributed packet broadcast by a wireless node is an early-set recognition signal transmitted by the AP, which in turn initiates the assignment process.

Assuming from Fig. 4 that the wireless node is initially located at 200, and is associated with AP1. It then communicates via AP1 with the X wired node. Because node A enters an area not covered by any AP, as indicated by reference 210, it cannot receive confirmations from AP1 for any packets it sends via AP1 to the node X. Therefore, he ceases to consider himself assigned to point AP1 because he can no longer maintain communication with point AP1. As node A enters the APA BSA, as indicated by reference numeral 220, it detects the presence of AP2 either by observing the AP2 recognition signal or the movement of the AP2. In this case, since AP2 did not hear node A at the location marked 200 or 210, AP2 may possibly determine that node A is the last node it heard and send the recognition signal beforehand. In either of these cases, node A initiates the mapping process to AP2. Re-connects node A to the network, allowing node A to connect again with node X. Assuming that the entire area is sufficiently covered by APs, node A can move around the entire area while remaining connected to the network.

The method of transferring data between nodes in the network described above with reference to Figs. 1, 2, 3 and 4 is implemented in a device for transferring data through nodes specific to the subject matter of which the block diagram of a non-network node is shown in Figure 5 Figure 6 is a block diagram of an interconnection node. The non-network node is constructed of functionally connected wireless adapter 300, transmitter 301, controller 302, memory 303, access circuit 304, redirection circuit 305 and determination circuit 306. In turn, the interconnection node is constructed of functionally connected wireless adapter 300, transmitter 301, third controller 311, fourth controller 313, memory 303, second memory 308, third memory 314, access circuit 304, redirection circuit 305, determining circuit 306, circuit 307 receiving, selector 310, offset circuit 312, comparator 315 and input circuit 316.

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Each node includes a wireless network adapter 300 for transmitting data over a wireless communications network from one node to other nodes in the network and for receiving data over a wireless communications network from those nodes, and a transmitter 301 for transmitting, along with each data message transmitted by the node via 300 wireless network adapter identification information for this node and for transmitting data to send a mapping request to the interconnection node. In addition, it includes a functionally connected controller 302 for controlling data received by the wireless network adapter 300, for extracting identification information from the data identifying other network nodes whose data is received, and extracting identification information determining whether each other node whose data has been received is identified in such information as interconnection node AP1, AP2, memory 303 for storing re-identifying information, whether this other node has been identified as interconnection node, memory access circuit 303 each time the node needs to send data to a specific other node other than the interconnection node to which it is assigned, and a circuit 305 for redirecting this data to the associated interconnection node , for further forwarding if the identification data for that particular node is not in memory 303. In addition, at interconnection node AP1, AP2, memory 303 is intended to store information identifying it as interconnection node. Non-interconnection node A, B, C, D, E, X contains the first table of identification information for other nodes that have been identified as interconnection nodes, and the second an array of identification information for nodes that have not been identified as interconnection nodes. In addition, non-network node A, B, C, D, E, X includes a circuit 306 for determining whether memory 303 contains stored identification information for a non-network node, one inter-network node or more than one inter-network node AP1, AP2, and transmitter 301 for transmit a mapping request to one interconnection node if the determination circuit 306 states that memory 303 contains stored identification information for one and only one interconnection node. After the circuit 306 determines that the memory 306 contains the stored identification information of more than one inter-network node that is not yet assigned to the inter-network node, it selects one of the inter-network nodes for which the memory 303 contains the stored identification information, and causes transmission. by transmitter 301, requests to assign to this selected one interconnection node. In turn, after the circuit 306 receives confirmation by the wireless network adapter 300 that this one interconnection node has accepted the assignment request, it enters a memory 303 indicating that this one interconnection node is assigned to the node of which the determination circuit 306 . Then, when the circuit 306 receives confirmation by the wireless network adapter 300 that the selected interconnection node AP1, AP2 has accepted the assignment request, it enters a memory 303 indicating that the selected interconnection node is assigned to the node of which the circuit 306 determination. The determination circuit 306 controls the transmission from the node of which it is a part to the interconnection node AP1, AP2, which is shown in memory 303 as assigned to the node of which it is a part, and clears the assignment record in memory 303 if the transmission from the node of which it is part , the interconnection node is not confirmed by the interconnection node.

Interconnection node AP1, AP2 includes a circuit 307 for receiving mapping requests from other nodes, and a second memory 308 for storing a list of all other nodes that have been assigned to that node by sending a mapping request that has been received by the node, and a transmitter 301 for transmitting messages to others interconnection nodes via a wired network each time the node receives a mapping request from another node, wherein the message notifies other interconnection nodes that this node has been assigned to such another node.

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The midnight node AP1, AP2 further includes a second data controller 309 in the wired network, a selector 310 for selecting data that is addressed to any node in the list, and the wireless network adapter 300 transmitting this data wirelessly at the node address of the list, a third controller 311 to controlling the wireless network adapter 300 with respect to messages directed to this node for their further forwarding by that node to a specific other node, a circuit 306 for determining if this particular other node is in the list, and a circuit 312 for directing the wireless network adapter 300 to re-broadcast the message to a specific other node if that particular other node is in the list, and the wired network adapter to be reset broadcasting a message on a wired network to the address of a specific other node if that particular other node is not on the list.

Interconnection node AP1, AP2 also includes a fourth controller 313 for controlling the wireless network adapter 300 in respect of receiving any messages, including those not directed to that node, a third memory 314 for remembering a list of all other nodes from which this message was received over a specified period of time, comparator 315 to determine if each of the new messages received has come from a node in the list, listing node 316 when a message arrives from a non-listed node that enters through the wireless network adapter 300 identification information that identifies the node each time a node receives a message from a non-listed node . a third controller 311 for controlling the wireless network adapter 300 with respect to the message to that node for its further forwarding by that node to a specific other node, and a circuit 312 for resetting the wireless network adapter 300 to retransmit the message to a specific other node.

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FIG. 2

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<img file="PL178035B1_D0002.tif" />

FIG. 3

210

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FIG. 4

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WIRELESS NETWORK ADAPTER. 300

301

TRANSMITTER

<img file="PL178035B1_D0004.tif" />

INTERNATIONAL NODE

FIG. 5

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<img file="PL178035B1_D0005.tif" />

THE INTERNATIONAL NODE

FIG. 6

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FIG. 1

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