JP2003516034A - Broadcasting as a trigger for route discovery. - Google Patents

Abstract

  (57) [Summary] A method and / or apparatus for adding a broadcast message for which a source waits for a reply message to a broadcast message for route discovery. The combined message is broadcast over the ad hoc network. When the combined message is received at the destination node, the destination node generates a response message that includes a reply message to the broadcast message that the source node waits for a reply. The response message is returned to the source node on the route that the combined message has traced to the destination node.

Description

Detailed Description of the Invention

BACKGROUND The present invention relates to ad hoc networks. More specifically, the present invention relates to routing in ad hoc networks.

Conventional network protocols are based on the characteristics and / or functions of fixed networks. In fixed networks, the network configuration generally does not change. Although it is possible to add and remove nodes within a fixed network, the route that data packets travel between two nodes is essentially unchanged. The disadvantage is that fixed networks cannot easily be reconfigured to handle the increase in data traffic, also called system load. Therefore, when the system load on a certain node increases, the surrounding nodes also suffer from an increase in delay in data transmission and reception.

In contrast to fixed networks, ad hoc networks are dynamic.
Ad hoc networks are formed when multiple nodes decide to join to form the network. Since the nodes in the ad hoc type network act as a host and a router, the ad hoc type network does not require the infrastructure required by the fixed type network. Therefore, ad hoc network protocols are based on the assumption that nodes are not always in the same physical location.

Bluetooth is a typical ad hoc network technology. Bluetooth is an open standard for wireless communication of voice and data. Based on short-range universal radio links, without the use of a fixed network infrastructure, connected devices such as printers, PDAs, desktop computers, fax machines, keyboards, joysticks, telephones or virtually any digital device Provide a mechanism for forming small ad hoc groups of devices that include. Bluetooth operates in the unlicensed 2.4 GHz Industrial Science and Medical (ISM) band.

FIG. 1 shows a Bluetooth piconet. The piconet is initially formed by two connected devices, referred to herein as Bluetooth devices. A piconet can contain up to eight Bluetooth devices. In each piconet, eg piconet 100, there is one master Bluetooth device and one or more slave Bluetooth devices. In FIG. 1, the Bluetooth device 101 is a master device, and the Bluetooth device 102 is a slave device.

According to Bluetooth technology, a slave device can only communicate directly with a master device. FIG. 2 shows a piconet in which a master device 201 and a plurality of slave devices 202-208 are arranged according to a star network topology. If the slave device 202 wants to communicate with the slave device 206, it must send the information that the slave device 202 wants to communicate to the master device 201. Then, the master device 201 transfers the information to the slave device 206.

A scatter network is formed by a plurality of independent and asynchronous piconets. FIG. 3 shows a typical scatter network. In FIG. 3, the piconet 1 includes a master node 303 and slave nodes 301, 302 and 304. The piconet 2 also includes a master node 305 and slave nodes 304, 306 and 307. The piconet 3 is the master node 309.
And slave nodes 308, 310 and 311. To implement a scatternet, it is necessary to use nodes that are members of multiple piconets. For example,
If node 301 wants to communicate with node 310, nodes 304 and 30
Eight will act as a forwarding node by forwarding the connection between the two piconets, specifically the connection between nodes 301 and 310. For example, node 3
01 transmits information to the master node 303 of Piconet 1. Master node 30
3 sends the information to the forwarding node 304. The transfer node 304 then transfers the information to the master node 305, which in turn sends the information to the transfer node 308. The forwarding node 308 sends the information to the master node 309,
The master node 309 sends the information to the destination node 310.

FIG. 4a shows the protocol layers of two conventional Bluetooth devices. As shown, devices 401 and 402 are high level protocols or applications 41.
Including 1. The devices 401 and 402 also include a network layer 421, a data link layer including a logical link control and adaptation protocol (L2CAP) 441 and a link manager protocol (LMP), and a physical layer including components for baseband.

In general, protocols that manage route formation and / or updates in ad hoc networks can be classified as either proactive or reactive. Proactive routing protocols attempt to update and maintain routes between nodes, including routes that are not currently in use. In general, proactive routing protocols react to changes in the network topology even if current traffic is not affected by the change. To update and maintain routes between nodes in an ad hoc network, each node periodically sends control information to other nodes in the network. But,
This requires a lot of signaling, consumes valuable bandwidth and leads to network congestion. Network congestion results in increased transmission delay of packets through the network.

In contrast to proactive routing protocols, reactive routing protocols establish routes only when needed to send a packet. Furthermore, reactive routing protocols maintain only information about the routes currently used to send data packets. Thus, reactive protocols provide less network signaling and thus less network congestion and delay when compared to proactive routing protocols.

Routing in an ad hoc network is based on source routing (source ro
can be implemented using either routing or distance vector routing. In both source routing and distance vector routing, a route request message is issued from the source node when the source node needs a new route to the destination node. In source routing, in response to a route request message, the source node receives all routes from the source node to the destination node in response messages. Therefore, only the source needs to know the route between the source node and the destination node. When a packet is sent from a source node to a destination node, all packets are given an overall route.

In the distance vector routing, each intermediate node stores the route information in the routing table when the response message is transmitted from the destination node to the source node. Therefore, the source node need only put the destination node address in each packet so that the packet reaches the destination node.

FIG. 5 shows a conventional source routing method. In step 505, the source node produces a message. At step 510, the node determines if the message is a broadcast or unicast message. If the message is a broadcast message, the source node broadcasts the packet to its neighbors following the "broadcast" path from decision step 510.

If the message is a unicast message, then according to the “unicast” path from decision step 510, it is determined according to step 520 whether the source node knows the route to the destination node. If the route to the destination node is known,
Following the "YES" path from decision step 520, in step 525, the source node sends a unicast message containing the entire route in the message to the node specified in the source node's routing table.

If the route to the destination is unknown, follow the “NO” path of decision step 520,
In step 530, the source node broadcasts a route request message. In step 535, the neighbor node receives the route request message. At step 540, the neighbor node determines if its route request message has already been processed. The adjacent cell makes this determination by checking the route included in the route request message in order to determine whether or not the address of the node itself is included in the route included in the route request message. If distance vector routing is used, the neighbor node will make this determination based on the source node address and the broadcast ID. If the neighbor node has already processed the route request message, the node discards the message according to the "YES" path from decision step 540 (step 545).

If the node has not processed the message yet, the decision step 540 reads “
According to the "NO" path, the node appends its address to the route request message in step 550. If distance vector routing is used, the node stores the source node address and the broadcast ID. In step 555, the node requests the route. Rebroadcast the message to neighboring cells, the node determines if it is the destination node in step 560. If it determines that the node is not the destination node, then it follows the "NO" path of decision step 560. Ends the processing for this message, but if the node is the destination node, the "YES" path of step 560 is followed and the destination node sources the response in step 565 via the route specified in the received message. Return to node, at step 570. Source node a unicast message, in accordance with. Reactive routing for transmitting over the newly established route to the destination node, the source node makes a request only when the broken route was actually used.

In conventional networks, there are generally two types of broadcast messages.
The first type of broadcast message is sent by the source node to disseminate the information to other nodes in the network. When this type of broadcast message is sent, the source does not wait for a reply message. The second type of broadcast message is a message waiting for the source node to receive a reply message from one or more network nodes.

Since ad hoc networks are dynamic, nodes can change their location within the network. When a node changes its location, it will have a different address than it had at its previous location. To send data from the source node to the destination node, the source node must first get its network address, resolve the destination name, get the destination node's hardware address, and determine the route to the destination node. Ah However, because conventional ad hoc routing protocols are based on characteristics and / or capabilities associated with fixed networks, conventional ad hoc routing protocols assume that the hardware addresses of source and destination nodes are known. .

A typical network protocol is the Internet Protocol (IP). In IP, there are several different broadcast messages generated by the source node, where the source node waits for reply messages from one or more nodes in the network. In IP, three typical types of broadcast messages where a source waits for a reply are Dynamic Host Configuration Protocol (DHCP), Name Resolution and Address Resolution Protocols. DHCP involves the dynamic allocation of IP addresses to nodes. Name resolution is used to obtain an IP address if the name of the node is known. ARP is used when the logical address of the node, for example, the IP address is known, but the hardware address of the node, for example, the Ethernet (registered trademark) address is unknown.

Therefore, in an ad hoc network, the source node must separately broadcast for DHCP, name resolution or ARP, and route discovery before it can start sending data to the destination node. . These separate broadcasts result in a delay in the transmission of information from the source node to the destination node.
Furthermore, sending these separate broadcasts adds load to the network.

Therefore, when using a source routing reactive protocol in an ad hoc network, it is desirable to minimize the number of broadcast messages needed to establish a route from a source node to a destination node. Similarly, when applying distance vector routing reactive protocols in ad hoc networks, it is desirable to minimize the number of broadcast messages needed to establish a route from a source node to a destination node.

SUMMARY OF THE INVENTION These and other problems, drawbacks and limitations of the prior art are due to the fact that the source stores a broadcast message waiting for a reply message in the broadcast message for route discovery. It is solved by the present invention. Combined messages are broadcast throughout the ad hoc network. When a combined broadcast message is received at the destination node, the destination node replies to the broadcast message where the source node awaits a reply.
Generate a response message containing the message. The reply message is returned to the source node along the route that the combined broadcast message followed to the destination node.

Accordingly, one object of the present invention is to minimize the amount of broadcast required for routing in ad hoc networks.

Another object of the present invention is to store a broadcast message in which a source node waits for a reply in a broadcast message that determines a route to a node that generates this reply message, thereby establishing a route in an ad hoc network. The goal is to minimize the network load.

It is also an object of the present invention to speed up the signaling required for routing between source and destination nodes and reduce the delay at the source node.

In accordance with one aspect of the invention, the above and other objects are directed from a source node to a destination node, where a route request broadcast message is used to discover and establish a route between the source and destination nodes. And / or apparatus for determining the route of The source node generates a broadcast message in which the source node waits for a reply message. The broadcast message is stored in the route request broadcast message.
The source node then broadcasts the route request broadcast message to neighboring nodes.

At each adjacent node, it is determined whether the individual node is the node generating the reply message. If the node itself generates a reply message, the reply message to the route request broadcast message is generated. The reply message is sent to the source node on the route contained in the route request broadcast message received by the node that generated the reply message. When distance vector routing is used, the reply message is sent to the source node on a temporary route stored by each neighbor node in the path between the source node and the node that generated the reply message. In the distance vector routing protocol, when the response message is transmitted from the node that generated the response message to the source node,
Each neighbor node in the route between the source node and the destination node activates the route.

According to another aspect of the present invention, the above and other objects are directed to a method for determining a route from a source node to another node, in which all nodes in the network include a network adaptation layer and an upper layer. And / or a device. At the upper layer of the source node, a broadcast message is generated in which the source node waits for a reply. This broadcast message in which the source node waits for a reply is stored in the network adaptation layer route request broadcast message. The network adaptation layer route request broadcast message is broadcast from the source node to neighboring nodes.

The objects and advantages of the present invention will be understood by reading the following detailed description in conjunction with the drawings.

DETAILED DESCRIPTION The present invention seeks to minimize the amount of broadcast messages sent during route discovery. Overall, the present invention accomplishes this goal by using a source routing approach, where the source node combines broadcast messages awaiting reply messages with route discovery broadcast messages. Alternatively, the present invention achieves this goal by using a distance vector routing approach, where the source node combines a broadcast message waiting for a reply message with a route discovery broadcast message. The broadcast message, in which the source node waits for a reply message, can then be used to support route discovery.

In the following, the present invention will be explained as a route discovery method used for Bluetooth scatternet. However, one of ordinary skill in the art will recognize that the present invention is applicable to wired or wireless networks, fixed networks and other types of ad hoc networks.

All broadcast messages should include the broadcast ID in the network adaptation layer header. In addition, the broadcast message should include a source address that uniquely identifies the source. For example, each Bluetooth device is called an invariant and globally unique 4 Bluetooth device address (BD_ADDR) when manufactured.
It is assigned an 8-bit IEEE 802 address. Therefore, the broadcast ID will uniquely identify a particular broadcast in combination with the source address.

6a and 6b show an exemplary method of using the route discovery broadcast message.
At step 602, the source node generates a broadcast message. In step 604, the source node determines whether the broadcast message is in the form that the source node waits for a reply. If the source node does not wait for the reply message,
Following the "No" path of decision step 604, the source node broadcasts the message to all neighboring nodes in step 606.

If the source node waits for a reply to the broadcast message, then in accordance with the “Yes” path of decision step 604, the source node piggybacks the broadcast message to the route request message in step 608. Further, if the source node cannot determine whether to wait for the reply message in response to the broadcast message, the source node follows the "Yes" path of decision step 604 to add the broadcast message to the route request message. In step 615, the source node broadcasts a route request message to its neighbors. For example, referring to FIG. 3, if node 303 was the source node, the broadcast message would be node 3
01, 302 and 304. Alternatively, the source node broadcasts the route request message only to the forwarding nodes.

In step 617, the route request message is received by the neighboring node.
At step 620, the neighbor node determines whether the node has already processed its route request message. The original routing packet contains the entire route for that packet, so the node has already processed the route request message by examining the message to determine if the route in the route request message includes its address. It can be determined whether or not. Alternatively, if distance vector routing is used, each node must have a source address and a broadcast ID.
Has a broadcast buffer that stores a set of The broadcast buffer also stores the time the message was received to determine if the node processed the broadcast message within a predetermined time. Those skilled in the art will set this predetermined time long enough that the node does not rebroadcast already broadcast messages, but short enough that the buffer does not require large memory. You will recognize that If the node's own address is included in the route request message,
Or, if distance vector routing is used, the step of determining if the set of source address and broadcast ID of the received message matches one of the set of source address and broadcast ID stored in the broadcast buffer. Following the "Yes" path of 620, the node discards the message in step 625.

If the node determines that it has not previously processed the route request message, then according to the “No” path of decision step 620, at step 640 the node determines if the appended data specifies itself as the destination node. To judge. When distance vector routing is used, when the node determines that it has not processed the route request message before, the node broadcasts the pair of source address and broadcast ID along with the time the route request message was received at the node. Store in buffer. It will also store a temporary route back to the source before examining the appended data. If the added data does not specify itself as the destination node, then in accordance with the "No" path of decision step 640, the node adds its address to the route contained in the route request message at step 658. If distance vector routing is used and the additional data does not specify itself as the destination node, the node replaces its address in the route request message. Step 66
At 0, the node rebroadcasts the route request message to its neighbors.
This process is performed at each node receiving the broadcast message, as indicated by the return path from step 660 to step 617.

When the added data indicates that the node is the destination node, the node adds the reply message to the route reply message in step 642 according to the “Yes” path in step 640. In step 645, the node sends the route response to the next node indicated by the route stored in the message. If distance vector routing is used, the node sends a route reply to the next node in the temporary route. In step 665, the next node examines the address of the message to determine if it is the source node. If the node is not the source node, the note follows the "No" path of step 665 and the note sends the route reply message to the next node indicated by the route in the route reply message. If distance vector routing is used, the node initiates a temporary route and sends a route reply message to the next node in the temporary route. If the node is the source node, then "Yes" in step 665.
According to the path, the node starts data transmission on the new route defined in its route reply message. If distance vector routing is used and the node is the source node, the node activates the route and starts data transmission on the new route. After the source node requests a route to the destination node,
Since there is a delay before the source node receives the route response, the source node can buffer the data packets it wants to send on that route. Alternatively, the source node may simply drop the packet. Since the destination node does not rebroadcast to surrounding nodes, surrounding nodes are not disturbed by route request broadcasting. This removes some of the load on the network.

It would be desirable to support IP in the Bluetooth Scatternet. However, Bluetooth cannot provide a true shared network, as it requires slave nodes to communicate via communication to the master node to send data to other nodes. Therefore, Bluetooth cannot support IP at this time.

FIG. 4b shows an example of a Bluetooth device capable of implementing IP. The Bluetooth device of FIG. 4b includes the network adaptation layers 461 and 462, except that the Bluetooth device of FIG.
Similar to the Bluetooth device of a. By using the network adaptation layer, the entire scatternet can be regarded as an IP subnet. Since the IP protocol layer assumes that a shared network exists, the network adaptation layer emulates a shared or broadcast network. The network adaptation layer provides the IP layer with a routing mechanism for routing information within the scatternet while emulating the scatternet as actually being a single shared network medium. Regardless of the routing mechanism implemented, the network adaptation layer uses the forwarding nodes described above to forward information from one piconet to another.

7a and 7b show an exemplary method for triggering route discovery in an IP network operating according to the source routing protocol and using DHCP, name resolution or ARP broadcast messages. As mentioned above, the source node is DH
When broadcasting a message for CP, name resolution or ARP, the source node waits for a reply message. The combination of DHCP, name resolution or ARP and route discovery reduces messages traversing the network. Therefore, the messages described in FIG. 7 are merely exemplary, and the method is equally applicable to other types of broadcast messages in which the source node waits for reply messages.

In step 705, the source node generates an ARP, name resolution or DHCP broadcast message and supplies it to the network adaptation layer. In step 710, the network adaptation layer attaches an ARP, name resolution or DHCP broadcast message to the network adaptation layer route request broadcast message. An additional indicator may be inserted in the network adaptation layer route request broadcast message to indicate that the network adaptation layer route request broadcast message contains either an ARP, name resolution or DHCP broadcast message. Alternatively, in a fixed length protocol, the length indicator, indicating that the route request message is longer than the normal fixed length, will implicitly indicate that the request contains additional data.

At step 715, the source node broadcasts a network adaptation layer route request broadcast message to its neighbors. In step 717, the node receives the route request message. At step 720, the neighbor node determines whether it has processed the route discovery request message. The neighbor node determines whether it has already processed the message by determining whether its address is in the route contained in the broadcast message. If the route discovery request message has already been processed, then the node discards the message in step 725, following the "Yes" path of step 720. If the node has not yet processed the route request message, then following the "No" path of step 720, the node appends its address to the route contained in the route request message at step 727. If distance vector routing is used and the node has not yet processed its route request message, the node saves the source node address in the broadcast ID pair and a temporary route back to the source node. In step 732, the additional data is transmitted to the upper protocol layer. In step 735, the node rebroadcasts the message to all neighboring nodes.

The node that rebroadcasts the message determines in step 740 whether or not it is the node that generates a reply message to the added broadcast message.
If the node is not a node that generates a reply message to the added broadcast message, the "No" path of decision step 740 is followed and the node does not perform any further processing on this message according to step 745. If the node that rebroadcasts the message is the node that generates the reply message to the added broadcast message, then in accordance with the “Yes” path of decision step 740, the node, in step 750, sends the ARP, name resolution or DHCP broadcast Generate a reply message to the message and add this reply to the network adaptation layer reply message. Replies to ARP, name resolution or DHCP broadcast messages are made by the node in a manner similar to the way the source node adds ARP, name resolution or DHCP broadcast messages. In step 760, the destination node sends back a network adaptation layer route reply message on the route contained in the route request message. If distance vector routing is used, the destination node activates the route within the node and sends a network adaptation layer route reply message back on the temporary route.

In step 765, the node in the route included in the route response message receives the route response message and determines whether or not it is the source node. If distance vector routing is used, the nodes in the temporary route receive the message. If the node is a source node, then following the "Yes" path from decision step 765, the node sends additional data to the protocol stack in step 767 and saves the route to the destination. The source node then starts sending data on the new route in step 769.

If the node is not the source node, then following the “No” path of decision step 765, in step 765 the node sends a route response message to the node next to the route indicated in this message. If distance vector routing is used and the node is not the source node, the node activates the route in the node and sends a route reply message to the next node in the temporary route.
Then, the next node follows step 765 to determine whether or not it is the source node. This process is repeated until the source node receives the route reply message.
Processing continues at each node along the route indicated in the route response message. If distance vector routing is used, this process continues at each node along the temporary route.

If the source node does not receive a reply to the route request message, eg the reply was discarded in the process of returning to the source or the route request message did not reach its destination, a protocol layer above the network adaptation layer layer, For example, ARP issues the broadcast again and the above method is repeated.

Since FIGS. 7a and 7b describe an exemplary embodiment in which the source node generates a broadcast message that it knows to wait for a reply, the broadcast message has the form that the source node waits for a reply. The step, such as step 604 of FIG. 6, in which the source node determines whether or not is not included in this figure. However, as described above with respect to FIG. 6, if the source node is not certain that it is waiting for a reply to its broadcast message, the source node will append the broadcast message to the route request message.

The routing methods shown in FIGS. 6 and 7 are similar, but one difference is noted.
There is one. In step 640 of FIG. 6, if it is determined that the node that received the route request message is the destination node, that node does not broadcast the route request broadcast message. In contrast, in FIG. 7, the network adaptation layer route request message is rebroadcast in step 735 before it is determined if the node is the node generating the reply message. Therefore, in the method of FIG.
The network adaptation layer will rebroadcast the network adaptation layer route request message even if that node is the node that generated the reply message. Rebroadcast,
This is due to the fact that the network adaptation layer does not know if some of its upper protocol layers generate ARPs, name resolutions or replies to DHCP messages. Therefore, in the method of FIG. 7, the network adaptation layer does not depend on the upper protocol layer. If the network adaptation layer relies on higher protocol layers, there will be a delay in the network adaptation layer before re-broadcasting the route request from the node. However, this also allows the node to prevent further flooding of the network with messages. To avoid further flooding of the network, the upper protocol layer may inform the network adaptation layer whether or not the upper layer broadcasts a trigger for route discovery. Alternatively, the network adaptation layer can be designed to recognize higher layer broadcasts and distinguish between broadcasts that trigger route discovery, eg ARPs and broadcasts that do not trigger route discovery.

8a, 8b, 9a and 9b show whether the node receiving the network adaptation layer route request broadcast message with data attached to the network adaptation layer in the node is the node generating the reply message. A method of making it possible to determine whether or not is shown. The steps of FIGS. 8 and 9 are similar to those of FIG. 7 with steps 735, 740 and 745 replaced by four new steps. In FIG. 8, steps 735, 740 and 745 correspond to steps 836, 838, 8
Replaced by 39 and 840. In step 836, the node sets a timer and the node's network adaptation layer looks at the data from the higher protocol layers. In step 838, the network adaptation layer is DHCP
, A name resolution or a reply to the ARP broadcast message is recognized. If the network adaptation layer recognizes the reply message, decision step 8
Following the "Yes" path from 38, the network adaptation layer appends the reply message to the route reply message at step 750. The remaining steps of the method operate similarly to the method described above with respect to FIG.

If the network adaptation layer does not recognize the reply message, decision step 8
Following the "No" path from 38, step 839 determines if the timer has expired. If the timer has not expired, "No" from decision step 839.
Following the path, the method returns to step 836 where the network adaptation layer continues to look at data from higher protocol layers. If the timer has expired, then following the "Yes" path from decision step 839, the node rebroadcasts the data at step 840. The method continues at step 717 where the next neighbor node receives the broadcast message.

Similar to the method of FIG. 8, FIG. 9 illustrates steps 735, 740 and 745 as step 9
36, 940, 942 and 945. In step 936, the node sets the timer while the upper protocol layer receives the additional data. At step 940, it is determined whether the upper protocol layer indicates that a response message to the additional data has been generated. If the upper layer indicates that a response message to the additional data has been generated, then the response message is added to the network adaptation layer response message in step 750 according to the "Yes" path from step 940. Again, the remaining steps of the method shown in FIG. 9 operate similarly to the method described in FIG.

If the upper protocol layer does not indicate that a response message to the additional data has been generated, then the “No” path of decision step 940 is followed to determine at step 942 whether the timer has expired. If the timer has not expired, the upper protocol layer continues processing additional data at step 936 according to the "No" path from decision step 942. If the timer has expired, then following the "Yes" path from decision step 942, the node rebroadcasts the message at step 945. At step 717, processing continues as if another neighbor node received the broadcast message.

6 to 9 show a typical method in which a broadcast message is processed by one adjacent node at the same time, those skilled in the art will understand that the broadcast message is
The neighbor will recognize that it will be processed when it receives the broadcast message. Accordingly, the broadcast message may be processed by some or all of the adjacent nodes at the same time or during similar time periods.

Another alternative embodiment is to trigger route discovery only for ARP broadcast messages. To implement this method, routing must be done at the network adaptation layer. Therefore, the network adaptation layer will be ARP dependent. This means that the network adaptation layer will understand the ARP request / reply message. For example, if the network adaptation layer uses Ethernet encapsulation, the network adaptation layer may send a message with an ARP request or A message.
The type field in the Ethernet frame will be examined to determine if it is an RP reply message.

The difference between this embodiment and the previous embodiments occurs in the node that generates the ARP reply message. According to this embodiment, the network application layer detects the ARP response from the upper layer as an ARP message with a unicast destination address. Similarly, at the node that generates the ARP response, the network application layer detects the ARP request as an ARP message with the broadcast address as the destination address. In the case of Ethernet encapsulation, the ARP request is detected as an Ethernet frame with the format set to ARP and the destination address set to the Ethernet broadcast address.
The ARP response is detected as an Ethernet frame with the format set to ARP and the destination address set to the unicast Ethernet address.

Since the methods described above relate to source routing protocols, nodes generally
It does not determine if the route to the cached destination is stored in the node. In ARP, name resolution and DHCP, ARP, name resolution and DH
The node that generates the reply message to the CP is the only node that can provide the information required for this reply message. Therefore, intermediate nodes with cached routes will not be able to provide this necessary information. If the broadcast is from an upper protocol layer, the node will not know which node is available. However, it is also possible to implement the network so that intermediate nodes have cached response messages for ARP, name resolution or DHCP messages. If this is done, the source node will receive two response messages for the route request message. The first message is ARP
, Will come from an intermediate node with name resolution or a cached reply message to DHCP. The second response will also include the established route and will come from the destination.

Combining route discovery with other broadcast messages reduces the load on the network. Furthermore, because of the combination of route discovery and other broadcast messages, the first route to the destination node is formed sooner. As a result, the buffering time at the source node is also reduced. The method and hardware implementation for route discovery described above identifies a route between a source node and a destination node while the source node sends other broadcast messages waiting for a reply message, which is simple, efficient, and Provide an accurate method. As a result, the present invention saves valuable network resources compared to conventional methods.

The invention has been described with reference to some representative embodiments. However, it will be apparent to one skilled in the art that the present invention may be embodied in specific forms other than the exemplary embodiments described above. This can be done without departing from the spirit of the invention. These representative embodiments are merely illustrative and should not be construed as limiting in any way. The scope of the invention is given by the appended claims rather than the above description, and it is intended that the derivatives and equivalents falling within the scope of the claims be included in the claims.

[Brief description of drawings]

[Figure 1]   It is a figure which shows a typical piconet.

[Fig. 2]   It is a figure which shows a typical star network.

[Figure 3]   It is a figure which shows the typical scatternet formed with several piconet.

Figure 4a   FIG. 3 is a diagram showing a protocol layer of a conventional Bluetooth device.

FIG. 4b is a diagram illustrating protocol layers of a Bluetooth device according to an exemplary embodiment of the present invention.

[Figure 5]   It is a figure which shows the conventional source routing route discovery method.

FIG. 6a

FIG. 6b is a diagram showing a representative method for performing route discovery using a source routing method in an ad hoc network.

FIG. 7a

FIG. 7b is a diagram showing an exemplary method for combining route discovery using a source routing approach and broadcast waiting for a reply message by a source node in an ad hoc network.

FIG. 8a

FIG. 8b is a diagram showing another exemplary method for combining route discovery using a source routing approach with broadcast waiting for a reply message by a source node in an ad hoc network.

FIG. 9a

FIG. 9b is a diagram illustrating yet another exemplary method for combining route discovery using a source routing approach and broadcasting a source node waiting for a reply message in an ad hoc network.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE, TR), OA (BF , BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, G M, KE, LS, MW, MZ, SD, SL, SZ, TZ , UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, B Z, CA, CH, CN, CR, CU, CZ, DE, DK , DM, DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, J P, KE, KG, KP, KR, KZ, LC, LK, LR , LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, R O, RU, SD, SE, SG, SI, SK, SL, TJ , TM, TR, TT, TZ, UA, UG, UZ, VN, YU, ZA, ZW (72) Inventor Serensen, Johann             Sweden Eslev S-241             91, Estra Stré 25 Holma F term (reference) 5K030 HC14 HD09 JL01 JL09 LB05                       LD02                 5K067 AA22 AA25 BB21 DD15 DD17                       DD51 EE12 EE16 FF13 KK13

Claims (56)

[Claims] 1. A method of determining a route from a source node to another node in a network, wherein a route request broadcast message is used to discover and establish a route between a source node and another node. In the source node, the step of generating a broadcast message in which the source node waits for a reply message, the step of adding the broadcast message to the route request broadcast message, and the source node to the adjacent node, Broadcasting the route request broadcast message, and determining in each of the neighboring cells whether or not it is the node that generates the reply message. 2. The method of claim 1, wherein the source node includes its address in the route request broadcast message. 3. The step of adding the address of the adjacent node itself to the route request broadcast message by each of the adjacent nodes, and to all the nodes adjacent to the adjacent node that received the route request broadcast message. Re-broadcasting said route request broadcast message. 4. When the neighboring cell is a node that generates the response message, generating a response message to the route request broadcast message, adding the response message to the response message, and 4. The method of claim 3, further comprising the step of sending a reply message to the source node on a route included in the route request broadcast message received by the node that generated the reply message. 5. A step of storing a temporary route for each of the adjacent nodes to return to the source node, and requesting the route to all nodes adjacent to the adjacent node receiving the route request broadcast message. Re-broadcasting the broadcast message. 6. When the neighboring cell is a node that generates the response message, generating a response message to the route request broadcast message, adding the response message to the response message, and Further comprising sending a response message to the source node on the temporary route stored at each neighbor node in the path between the source node and the node that generated the reply message. The method of claim 5 characterized. 7. When the response message is transmitted from the node that generates the reply message to the source node, at each adjacent node in the path between the source node and the node that generated the reply message. 7. The method of claim 6, further comprising the step of activating a route. 8. The method of claim 1, wherein the source node, the neighbor node and the node that generates the reply message are part of an ad hoc network. 9. The method of claim 1, wherein the source node, the neighbor node, and the node that generates the reply message form a scatter network. 10. The method of claim 1, wherein the source node, the neighbor node, and the node that generates the reply message operate according to the Bluetooth protocol. 11. In each of the adjacent nodes, a step of receiving the route request broadcast message, a step of setting a timer, the route request broadcast message including a broadcast message in which the source node waits for a reply message. Examining the route request broadcast message to determine whether it contains; and if the route request broadcast message is the broadcast message in which the source node waits for the reply message, the neighbor node itself The method according to claim 1, further comprising the step of determining whether the node generates a reply message. 12. The method further comprising the step of re-broadcasting the route request broadcast message if the adjacent node itself has not been determined to be the node generating the reply message after the expiration of the timer. The method according to claim 11, wherein 13. The method further comprises the step of generating a response message to the route request broadcast message if it is determined that the adjacent node itself is the node generating the reply message before the expiration of the timer. The method according to claim 11, wherein: 14. The method of claim 13, wherein the response message comprises the reply message. 15. The method further comprising the steps of setting a timer and determining whether the upper protocol layer has sent a notification to the lower protocol layer that the reply message was generated. The method described in 1. 16. The method further comprising the step of rebroadcasting the route request broadcast message if the upper protocol layer has not sent a notification that the reply message was generated after the expiration of the timer. 16. The method of claim 15 characterized. 17. If the upper protocol layer is sending a notification that the reply message has been generated before the expiration of the timer, the method further comprises the step of generating a response message to the route request broadcast message. 16. The method according to claim 15, characterized in that 18. The method of claim 1, wherein the broadcast message in which the source node waits for a reply message is formed according to Address Resolution Protocol (ARP). 19. The method of claim 1, wherein the broadcast message in which the source node waits for a reply message is formed according to a name resolution protocol. 20. The method of claim 1, wherein the broadcast message in which the source node waits for a reply message is formed according to Dynamic Host Configuration Protocol (DHCP). 21. A method of determining a route from a source node to another node in a network in which all nodes include a network adaptation layer and an upper protocol layer, wherein the source node is the upper protocol layer of the source node. A step of generating a broadcast message waiting for a reply message, a step of adding, to the network adaptation layer route request broadcast message, a broadcast message in which the source node waits for a reply message, and from the source node to an adjacent node, Broadcasting the network adaptation layer route request broadcast message. 22. The method of claim 21, wherein the route request broadcast message includes an address of the source node. 23. A step of adding the address of the adjacent node itself to the route request broadcast message by each of the adjacent nodes, and to all nodes adjacent to the adjacent node receiving the route request broadcast message. 23. The method of claim 22, further comprising rebroadcasting the route request broadcast message. 24. The method further comprising setting a timer, and determining whether an upper protocol layer has sent a notification to the network adaptation layer that the reply message was generated. The method of claim 21. 25. The method further comprising the step of rebroadcasting the route request broadcast message if the upper protocol layer has not sent a notification that the reply message was generated after the timer expires. The method of claim 24, wherein the method is characterized. 26. When the upper protocol layer sends a notification that the reply message has been generated before the expiration of the timer, the network adaptation layer sends a response message to the route request broadcast message. 25. The method of claim 24, further comprising the step of generating. 27. The method of claim 22, wherein the network operates according to a source routing protocol. 28. The method of claim 21, wherein the network operates according to a distance vector routing protocol. 29. The method of claim 21, wherein the upper layer operates according to Internet Protocol (IP). 30. For determining a route from the source node to the other node in a network where a route request broadcast message is used to discover and establish a route between the source node and the other node. A device, in the source node, means for generating a broadcast message in which the source node waits for a reply message, means for adding the broadcast message to a route request broadcast message, and from the source node to an adjacent node. On the other hand, an apparatus comprising means for broadcasting the route request broadcast message, and means for judging whether or not each of the adjacent cells is a node which generates the reply message. 31. The apparatus of claim 30, wherein the route request broadcast message includes an address of the source node. 32. Means for adding, by each of the adjacent nodes, the address of the adjacent node itself to the route request broadcast message, and all of the adjacent nodes that have received the route request broadcast message. 32. The apparatus of claim 31, further comprising means for rebroadcasting the route request broadcast message to a node. 33. When the adjacent cell is a node that generates the response message, a unit that generates a response message to the route request broadcast message; a unit that adds the response message to the response message; 33. The apparatus of claim 32, further comprising means for sending a reply message to the source node on a route included in the route request broadcast message received by the node that generated the reply message. 34. Means for storing a temporary route for each of the adjacent nodes to return to the source node, and the route request to all nodes adjacent to the adjacent node receiving the route request broadcast message. 31. The apparatus of claim 30, further comprising means for rebroadcasting a broadcast message. 35. When the adjacent cell is a node that generates the response message, a unit that generates a response message to the route request broadcast message; a unit that adds the response message to the response message; Further comprising means for sending a reply message to the source node on the temporary route stored at each neighbor node in the path between the source node and the node that generated the reply message. The device of claim 34, wherein the device is characterized. 36. When the response message is sent from the node that generates the reply message to the source node, at each adjacent node in the path between the source node and the node that generated the reply message. 36. The apparatus of claim 35, further comprising means for activating a route. 37. The apparatus of claim 30, wherein the source node, the neighbor node and the node that generates the reply message are part of an ad hoc network. 38. The apparatus of claim 30, wherein the source node, the neighbor node and the node that generates the reply message form a scatter network. 39. The apparatus of claim 30, wherein the source node, the neighbor node, and the node that generates the reply message operate according to the Bluetooth protocol. 40. In each of said adjacent nodes, means for receiving said route request broadcast message, means for setting a timer, said route request broadcast message is a broadcast message for which said source node waits for a reply message. Means for examining the route request broadcast message to determine whether it contains, and if the route request broadcast message is the broadcast message in which the source node waits for the reply message, the neighbor node itself 31. The apparatus according to claim 30, further comprising means for determining whether the node generates a reply message. 41. The method further comprising means for re-broadcasting the route request broadcast message when the adjacent node itself has not been determined to be the node generating the reply message after the expiration of the timer. The device according to claim 40. 42. The method further comprises means for generating a response message to the route request broadcast message when it is determined that the adjacent node itself is the node generating the reply message before the expiration of the timer. 41. The device according to claim 40, characterized in that 43. The apparatus of claim 42, wherein the response message comprises the reply message. 44. Means for setting a timer, and means for determining whether or not the upper protocol layer has transmitted to the lower protocol layer a notification that a reply message has been generated. 30. The device according to item 30. 45. Further comprising means for re-broadcasting said route request broadcast message if said upper protocol layer has not sent a notification that said reply message was generated after said timer expires. The device of claim 44, wherein the device is characterized. 46. Further comprising means for generating a response message to the route request broadcast message if the upper protocol layer has sent a notification that the reply message has been generated before the expiration of the timer. 45. The device of claim 44, characterized in that 47. The apparatus of claim 30, wherein the broadcast message in which the source node waits for a reply message is formed according to Address Resolution Protocol (ARP). 48. The apparatus of claim 30, wherein the broadcast message in which the source node waits for a reply message is formed according to a name resolution protocol. 49. The apparatus of claim 30, wherein the broadcast message in which the source node waits for a reply message is formed according to Dynamic Host Configuration Protocol (DHCP). 50. An apparatus for determining a route from a source node to another node in a network in which all nodes include a network adaptation layer and an upper protocol layer, wherein the source node is the upper protocol layer of the source node. Means for generating a broadcast message waiting for a reply message, a means for adding a broadcast message in which the source node waits for a reply message to the network adaptation layer route request broadcast message, and from the source node to an adjacent node, Means for broadcasting the network adaptation layer route request broadcast message. 51. The apparatus of claim 50, wherein the route request broadcast message includes an address of the source node. 52. Means for adding, by each of the adjacent nodes, the address of the adjacent node itself to the route request broadcast message, and all of the adjacent nodes adjacent to the adjacent node receiving the route request broadcast message. 52. The apparatus of claim 51, further comprising means for rebroadcasting the route request broadcast message to a node. 53. Further comprising means for waiting for a predetermined time, and means for judging whether or not an upper protocol layer has sent a notification to the network adaptation layer that the reply message has been generated. The device of claim 50. 54. Further comprising means for rebroadcasting said route request broadcast message if said upper protocol layer has not sent a notification that said reply message was generated after said predetermined time. 54. The apparatus according to claim 53. 55. A response message to the route request broadcast message is generated in the network adaptation layer when the upper protocol layer sends a notification that the reply message is generated during the predetermined time. 54. The apparatus of claim 53, further comprising means for: 56. The apparatus of claim 50, wherein the upper layer operates according to Internet Protocol (IP).