CN101536435A

CN101536435A - Method for establishing bidirectional data transmission paths in a wireless meshed communication network

Info

Publication number: CN101536435A
Application number: CNA2007800420754A
Authority: CN
Inventors: M·巴尔; A·巴图
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2006-11-13
Filing date: 2007-11-12
Publication date: 2009-09-16

Abstract

The invention relates to a method for establishing a bidirectional data transmission path in a wireless meshed packet-switched communication network, wherein a logical topology in the form of at least one routing tree can be proactively established, wherein a root network node (R) of the routing tree sends first unidirectional data transmission paths regarding routing request messages (RANs) specifying the root network node (R) to the network nodes (M1-M7) of the communication network in periodic time intervals. A first flag is provided in the network nodes (M1-M7) of the routing tree that can be put into two different states. Upon receipt of a routing request message (RAN), a network node (M5) only sends a second unidirectional data transfer path regarding the routing response message (RWN) specifying the network node to the root-network node (R) if the first flag is switched into a first selectable state (ON). Thus, a bidirectional data transfer path between the root network node (R) and the network node (M5) is established.

Description

Be used for realizing the method for bidirectional data transmission paths in wireless mesh communications network

Technical field

The present invention is in the technical field of message technology, and relates to a kind of method that realizes bidirectional data transmission paths in wireless network trellis communication network.The invention still further relates to a kind of suitable wireless network trellis communication network that is used to carry out this method.

Background technology

For wireless WLAN communication network (WLAN=WLAN (wireless local area network)), since the early 1990s just by Institute of Electrical and Electric Engineers (IEEE) a lot of different standards are disclosed in the framework of standard series IEEE802.11, in these standards, stipulated the characteristic of determining of communication network, as transfer rate, frequency range, modulator approach, channel quantity, encryption or the like based on the technical research of quick progress with retraining.

In present standard, the least unit of WLAN communication system is a wireless area, in wireless area access point can with a plurality of terminal equipment swap datas.The connection each other of a plurality of wireless areas connects by the cable between the access point to be carried out.

A kind of latest developments in standard series IEEE802.11, it is accurate and disclosed progress has been carried out standardization to the radio communication between the network node at 2009 year's harvest criterion of making a living just to be called IEEE802.11s and expectation meeting.In IEEE802.11s, network node, promptly so-called grid point (being abbreviated as MP (Mesh Point)) forms wireless latticed Ad-hoc wireless network (mesh network) thus with acting on the router that carries out wireless data transmission.

In communication network, generally can implement to answer earlier Routing Protocol formula, reaction equation or that mix.

Answer earlier in the communication network of formula Routing Protocol in employing, between source network node and target network node, be ready to data transfer path to be used to transmit data, this makes and can carry out the fast data exchange, thereby but especially exists resource to be retained the shortcoming that possibly can't be used for exchanges data.In the reaction equation Routing Protocol, the data transfer path between source network node and the target network node is just set up when needed, though this is more favourable with regard to resource, has brought time of delay for setting up data transfer path.

In order to utilize the advantage of answering formula Routing Protocol and reaction equation Routing Protocol earlier, for cordless communication network based on standard IEEE 802.11s, the have title HWMP mixing Routing Protocol of (Hybrid WirelessMesh Protocol, hybrid wireless grid agreement) is set in order to select the data transfer path between source network node and the target network node.In HWMP, on the physical topological structure of network, set up the logical topology of one or more routing tree forms.In order to set up and to upgrade routing tree, a root MP sends to other MP with routing inquiry message according to broadcasting method with the periodic time interval, these routing inquiry message are called " answering the formula path request earlier ", are abbreviated as and answer formula PREQ (PREQ=Path Request, path request) earlier.MP receives PREQ, corresponding path data is entered in their routing table, and sets up in this way from MP to the one-way data transmission path that sends root MP.For the quantity of the route messages that will be used to set up local routing tree keeps fewly as much as possible, can formerly answer to remove among the formula PREQ and be used for route response message PREP (PREP=Path Reply, path responses) what is called is answered formula PREP sign earlier, that is to say, MP receives and answers formula PREQ earlier, the forward path that be used to transmit data of foundation from MP to root MP, but route response message (PREP) is not sent to root MP, thus the reverse path that being used to from root MP to MP transmit data do not set up.

Because the root MP and the data flow between the MP of routing tree are normally two-way, therefore in HWMP, exist in the beginning of data communication, just also before first packet sends to root MP from a MP, just send the possibility of route response message (PREP) to root MP, thereby set up unidirectional reverse path in this way from root MP to the MP that sends this PREP from this MP.

By the PREQ that periodically sends from root MP, upgrade one-way data transmission path (forward path) periodically, thereby the condition that constantly changes in the unidirectional forward path of routing tree and the mesh network can be complementary from MP to root MP.Especially can be incorporated in the routing tree to the new MP that adds of this mesh network, perhaps for example change no longer workable data transfer path owing to the fault of data link.

But, because the reverse path from root MP to MP can not upgrade, and remained before first packet that sends data communication by send such that PREP set up from MP, therefore the forward situation different in the time of may appearing at the constant and link metric (Link-Metriken) of connectivity and change between root MP and the MP with reverse path, thereby (through what upgrade) more favourable route is taked in packet on forward path, and takes (process is not upgraded) not too favourable route on reverse path.If the data link in the data transfer path between root MP and MP breaks down, then the PREQ that sends by the cycle sets up the replacement forward path between root MP and this MP, on the contrary, and can't be again by carrying out transfer of data without the reverse path that upgrades.In this case, visit is based on the standard mechanism of AODV (Ad Hoc On DemandDistance Vector, Ad Hoc is distance vector as required) in HWMP, and this has brought and has begun the long time of delay before this MP transmission of data packets from root MP.

Summary of the invention

Therefore, the technical problem to be solved in the present invention provides a kind of method of setting up bidirectional data transmission paths in wireless mesh communication network, utilizes this method can avoid shortcoming above-mentioned.

This technical problem solves by a kind of method of setting up bidirectional data transmission paths in wireless mesh communication network with feature of claim 1 according to the present invention.Favourable execution mode of the present invention provides by the feature of dependent claims.

According to the present invention, showed a kind of method of in wireless netted packet switching (Ad-hoc) communication network, setting up bidirectional data transmission paths, on the physical topological structure of this communication network, answered formula ground to set up logical topology structure earlier with at least one tree structure (routing tree).For this reason, the network node of the root network node that is used as this routing tree of this communication network produces routing inquiry message with the periodic time interval, be abbreviated as RAN (Routing AnfrageNachricht), and send to the network node of communication network, lead to the first one-way data transmission path of root network node with setting.For this reason, can be when receiving this RAN by a network node in the routing table (sending table) of the network node that receives this RAN of this network, for target network node (root network node) deposits in or upgrades clauses and subclauses, next jumping (Hop) that these clauses and subclauses comprise path metric (Pfadmetrik) and lead to target network node (that is to say, at the next network node that leads on the path of target network node, this next network node is the network node that has obtained RAN).In addition, for example can also in routing table, deposit the number of jumping in.The method that is used for setting up routing tree especially can be based on mixing the process that Routing Protocol HWMP implements.Especially routing inquiry message (RAN) can be to answer formula path request (PREQ) earlier according to what mix Routing Protocol HWMP.

In the network node of routing tree, foundation can place first sign of two different conditions to control the transmission of route response message.If first sign of a network node of routing tree is placed in selectable first state, then this network node produces route response message when receiving routing inquiry message (RAN) from the root network node, be abbreviated as RWN (Routing AntwortNachricht), and this route response message is sent to the root network node by the network node that is included in the first one-way data transmission path.If first sign of a network node of routing tree is placed in second state, then this network node is not producing RWN when the root network node receives RAN.By this RWN, the second one-way data transmission path from the root network node to the network node that produces this RWN is set.For this reason, can be when receiving RWN by a network node, in routing table (sending table), deposit in or upgrade clauses and subclauses at the network node that produces RWN, these clauses and subclauses comprise path metric and lead to next jumping (Hop) of the network node that produces this RWN (just at the next network node on the path of the network node that produces this RWN, this next network node is the network node that has obtained this RWN).In addition, can in routing table, deposit the number of jumping in.Especially, route response message (RWN) can be according to the path responses (PREP) of mixing Routing Protocol HWMP.The root network node receives route response message (RWN), and set up the second one-way data transmission path from the root network node to the network node that produces this RWN, thus at the root network node with produce between the network node of this RWN and set up two-way data transfer path.

In communication network inside, packet sends another network node same one deck (osi model) to from a network node.This especially the 2nd layer or the 3rd layer.

By method of the present invention, just between the root network node of routing tree and network node, set up bidirectional data transmission paths when only packet is transmitted actually in an advantageous manner on data transfer path, thereby the quantity of route messages is fewer.In addition, except forward path from this network node to the root network node, also upgrade reverse path from the root network node to this network node, it is used that thereby the bidirectional data transmission paths through upgrading between root network node and the network node offers transmission of data packets, and can to may since the change of the change of path metric or the data transfer path that causes owing to the fault of data link react fast.

Under first state of first sign, first sign for example is " set ", just is placed in state " ON (opening) " or " 1 ", and this first sign is " removing " under second state, just is placed in state " OFF (pass) " or " 0 ".Equally, first sign can be placed state " OFF (pass) " under its first state, and under its second state, place state " ON (opening) ".

In the preferred implementation of the inventive method, if a network node of routing tree as communication network on the data transfer path that leads to the root network node first network node (source network node) and obtain to send to the packet of root network node (target network node), then first sign with this network node places first state.This network node obtains this packet from a layer (osi model) in this case, and this floor height is in the layer of the data packet transmission in inside communicates network.The mode that can especially simply implement is set up the bidirectional data transmission paths from the root network node to this network node as required thus.

In another preferred implementation of the inventive method, first sign of a network node is right after having sent route response message (RWN) to the root network node places second state afterwards, its advantage is the operation of this measure at Routing Protocol.Do not need timer in addition.

In another preferred implementation of the inventive method, first sign of a network node is just placed second state after selectable very first time interval elapses, this very first time at interval will be along with sending packet to the root network node as target network node and starting, this network node is the source network node of this packet, (this packet is that this network node obtains as first network node on the data transfer path that leads to the root network node at communication network), wherein said very first time, to send this this network node be source network node and root network node when being the packet of target network node each at interval, all is reset to the initial value of this optional time interbody spacer.This execution mode of the inventive method can be implemented especially simply.

In another preferred implementation of the inventive method, (this network node of this packet obtains as first network node of communication network on the data transfer path that leads to the root network node if network node receives packet as source network node, be used to send to the root network node), and not obtaining packet as source network node in the second certain time interval that is right after before receiving this packet (that is to say, do not have to obtain to send to the packet of root network node as first network node of communication network on the data transfer path that leads to the root network node), then this network node produces route response message (RWN) and sends to the root network node.Can advantageously when beginning, each data communication between root network node and this network node, set up bidirectional data transmission paths thus.

Especially in the last-mentioned execution mode of the inventive method, if second sign that is provided with in network node, can place two kinds of different conditions is placed in selectable second state, then this network node can produce route response message (RWN) and send to the root network node.This makes can realize method of the present invention especially simply.

In first state of second sign, second sign just places state " ON (opening) " or " 1 ", and is " cleared " at its second state for example by " set ", just is placed in state " OFF (pass) " or " 0 ".Equally, second sign can be placed state " OFF (pass) " under its first state, and under its second state, place state " ON (opening) ".

In another execution mode of the inventive method, for packet is the situation of first packet of data communication, this situation for example can be by placing its second state to discern second sign, if network node sends route response message (RWN) to the root network node before in first packet (D1) of data communication, then first sign with this network node places first state.Must the additional condition of inquiry but this causes.

In another execution mode of the inventive method, directly receiving routing inquiry message (RAN) afterwards to root network node transmission route response message (RWN).In the replacement execution mode of this execution mode, after receiving routing inquiry message (RAN), postpone just to send route response message (RWN) to root network node (R) through the regular hour.The substitute mode of mentioning later is preferred according to the present invention, because this substitute mode has the advantage of the quantity that can reduce route messages, because reduced the probability that receives other routing inquiry message (RAN) of better path metric after sending RWN.

In another preferred implementation of the inventive method, the life parameter of the route response message (RWN) of the life-span coding of the second one-way data transmission path of leading to network node is set to be included in the routing inquiry message (RAN) of reception, to the life parameter of the life-span coding of the first one-way data transmission path that leads to root network node (R).Can advantageously realize thus: the forward path of the bidirectional data transmission paths between root network node and network node is identical with the life-span of reverse path.

In addition, the invention still further relates to a kind of method of setting up bidirectional data transmission paths in aforesaid wireless mesh packet-switched communication networks network, this method especially can combine with said method.In the method, if first sign is placed in its selectable first state, then getting access to the first one-way data transmission path that leads to the root network node when changing first, send the route response message (RWN) of specifying the second one-way data transmission path that leads to this network node to the root network node, between root network node and this network node, set up two-way data transfer path thus.

The present invention also extends to aforesaid wireless mesh packet switching (Ad-hoc) communication network, and this communication network is constructed to realize aforesaid method.

In addition, the present invention also extends to the network node of (Ad-hoc) communication network of aforesaid wireless mesh packet switching, implements above-mentioned machine readable program code on this network node.

In addition, the present invention also extends to storage medium, has the machine readable as mentioned above program code that is stored on this storage medium.

Description of drawings

Explain the present invention in detail by embodiment now, wherein will be with reference to accompanying drawing.

Fig. 1 illustrates the embodiment of the wireless mesh communications network of the present invention of having set up routing tree with schematic diagram;

Fig. 2 with in the communication network that illustrates out Fig. 1 as source node to the transmission of the transmission of data groupings D1 and non-source network node to data grouping D2;

Fig. 3 illustrates the embodiment of the inventive method with schematic diagram, and this embodiment implements on the network node of the communication network of Fig. 1;

Fig. 4 illustrates another embodiment of the inventive method with schematic diagram, and this another embodiment implements on the network node of the communication network of Fig. 1.

Embodiment

The embodiment of the Ad-hoc communication network (mesh network) of wireless mesh packet switching of the present invention shown in Figure 1.This mesh network comprise a plurality of network nodes (grid point) R, M1, M2 ..., M7 (for example is 8 at this), they by 14 PPDL point-to-point data link L1 wireless, physics, L2 ..., L14 interconnects nettedly.Thereby for example root network node R is by the first data link L1 and the 3rd network node M3, by the 3rd data link L3 and the second network node M2, by the 6th data link L6 and the first network node M1 data technique ground wireless connections.In addition, for example the second network node M2 is connected with the 3rd network node M3 data technique ground by the 8th data link L8.All can be understood in a similar way to other explanation of data link and network node.

In the mesh network of Fig. 1, foundation from as the root network node R of root node to all-network node M 1, M2 ..., M7 answer the formula routing tree earlier, the data link that wherein belongs to this routing tree, the just first data link L1, the 3rd data link L3, the 6th data link L6, the second data link L2, the 4th data link L4, the 5th data link L5 and the 7th data link L7, in Fig. 1, represent, and the remainder data link that does not belong to routing tree is represented with the fine rule that disconnects with solid thick line.

The foundation of routing tree is based on the standard mechanism under the situation that adopts distance vector and link-state protocol, as what provide in the Routing Protocol HWMP of IEEE802.11s.Thereby root network node R with broadcasting method periodically to the all-network node M 1 of communication network, M2 ..., M7 sends routing inquiry message (RAN), these routing inquiry message specified the data transfer path that leads to the root network node and be used to upgrade network node M1, M2 ..., the routing table of M7.Thus respectively from network node M1, M2 ..., M7 sets up unidirectional data transfer path to be used for transmitting useful data grouping to root network node R.Thereby, for example pass through the second data link L2 and the first data link L1 from the 7th network node M7, under situation about connecting in the middle of the 3rd network node M3, set up the one-way data transmission path to root network node R with answering formula earlier.In addition, for example pass through the 5th data link L5 and the 3rd data link L3, under situation about connecting in the middle of the second network node M2, set up the one-way data transmission path with answering formula earlier to root network node R from the 5th network node M5.All other from network node M1, M2 ..., M7 understands in the corresponding way to the one-way data transmission path that the formula of answering earlier of root network node R is set up.

Network node M1, M2 ..., set up RWN response sign among the M7 respectively as first sign, this first sign can be set (" 1 ") or remove (" 0 ").

Network node M1, M2 ..., also set up RWN among the M7 and sent sign as second sign, this second sign can be set (" 1 ") or remove (" 0 ").

If network node M1, M2 ..., RWN response sign is set among the M7, and the RAN that this network node acquisition periodically sends from root network node R, then this network node response message (RWN) sends to root network node R, so that set up reverse path to be used for transmission (useful) packet from root network node R to this network node.If network node M1, M2 ..., RWN response sign is set among the M7, and this network node is for example learned by the failure message that the characterization data link breaks down, data transfer path from this network node to the root network node changes, then this network node also sends response message RWN to root network node R in this case, to set up reverse path from root network node R to this network node to be used for transmission (useful) packet.RWN is the message of (PREP) type of providing in the Routing Protocol HWMP of standard IEEE 802.11s, but only sends before data communication begins in this standard, just sends before sending first packet.

In order in network node M1, M2 .., M7, RWN to be responded flag set or removing, importantly whether network node M1, M2 .., M7 receive packet from higher layer, this higher layer is on the based on wireless mesh network layer that is being provided with between the network node for transmission of data packets in communication network, and perhaps whether network node only receives packet from another network node.

Explain in detail below with reference to Fig. 2.The packet that is source network nodes with those network nodes for them in Fig. 2 is expressed as packet " D1 ", is not that the packet of source network node is expressed as packet " D2 " with those network nodes.Packet D1 is from higher layer (osi model), as application layer, internet protocol layer or IEEE802.11D-Bridging, they one are reinstated S2 and represent in Fig. 2, and packet D1 is as being transferred to wireless clathrum representing by the arrow of downward sensing among Fig. 2, this clathrum is used for the transfer of data of mesh network inside and represents with S1 at Fig. 2, and this packet D1 transmits between network node then.Different therewith is that packet D2 is sent to another network node from a network node in wireless clathrum S1.Thus, same network node is a source network node for packet D1, is not source network node just for packet D2.Target network node is delivered to packet D2 among one of higher layer S2, and this is not shown specifically in Fig. 2.Have only from the network node of higher layer S2 acquisition packet D1 to be only source network node, and these network nodes are to RWN response flag set and removing.The network node from more high-rise S2 acquisition packet D1 is not a source network node, thereby not to RWN response flag set and removing.

In to the initialized process of wireless mesh communication network, all RWN response signs of network node M1, M2 .., M7 all (are pre-seted ground) and are removed (0).Equally, in to the initialized process of wireless mesh communication network, all RWN of network node M1, M2 .., M7 have sent sign and (have been pre-seted ground) and remove (0).

Root network node R periodically injects RAN to mesh network, thereby each network node can be entered into the data transfer path that leads to root network node R accordingly in the routing table of this network node after receiving RAN.If network node receives RAN, then in the routing table (pushing table) of the network node of this RAN of reception of network, deposit in or upgrade clauses and subclauses at target network node (root network node), next jumping that these clauses and subclauses comprise path metric and lead to target network node is just at the next network node that leads on the path of target network node.In addition, the number of jumping can be deposited in the routing table.The method that is used for setting up routing tree is being based on mixing the process that Routing Protocol HWMP implements, and wherein routing inquiry message (RAN) is to answer formula path request (PREQ) earlier according to what mix Routing Protocol HWMP.Whether this method step is that source network node is irrespectively carried out by all-network node and these network nodes.

Exemplarily supposition below, the 5th network node M5 obtains packet D1 from more high-rise S2, thus serves as source network node.

If the 5th network node M5 receives the query messages RAN that periodically sends from root network node R, then the 5th network node M5 will be entered in the routing table of the 5th network node M5 with this RAN data designated transmission path, perhaps rewrite present clauses and subclauses, upgrade the one-way data transmission path that the 5th network node M5 leads to root network node R thus periodically.

When sending packet D1 to root network node R, just also before first packet that sends data communication, the 5th network node M5 produces route response message RWN and also sends to root network node R in inquiry.Root network node R receives this RWN, and the data transfer path that will lead to the 5th network node M5 accordingly is entered in the routing table of root network node R, thereby set up one-way data transmission path (reverse path), between root network node R and the 5th network node M5, set up two-way data transfer path thus from root network node to the five network node M5.

All packets that sent by the 5th network node M5 behind last data grouping D1 in the time interval of determining all are called as " other " packet.If the 5th network node M5 does not send packet D1 in the described time interval, then each packet that then sends after this time interval finishes all is called as " first " packet.But by this preset time at interval, distinguish different " data communication ".

It is other packet of " first " packet or same data communication that the 5th network node M5 can come specified data grouping D1 by the state that its RWN has sent sign.If before first packet D1, send RWN, perhaps under the situation that RWN response sign is set, respond the RAN that is obtained and send RWN, then RWN has been sent flag set, just place " ON/1 "., remove RWN and sent sign at RWN response sign will impel RWN to send when being set RAN by each acquisition, just place " OFF/0 ".

In addition, can also guarantee that thus can not remove RWN mistakenly when obtaining the 2nd RAN of current root announcement (Root-Announcement) has sent sign, can not send RWN based on the 2nd RAN, because the path metric of the 2nd RAN is poorer than the path metric of a RAN to the root network node.RWN has sent sign and has not allowed now to be reset, otherwise will send another RWN before next packet D1.

Advantageously, only when removing RWN response sign, just remove RWN and sent sign.If should between RWN and affiliated RWN, send packet D1 thus, just can not send additional RWN.

Sent sign if in the 5th network node M5, remove RWN, then regarded packet D1 as first packet, on the contrary,, then regarded packet D1 as other packet if in the 5th network node M5, RWN has been sent flag set.

In the first flag set deformation program of the inventive method, if send response message RWN based on first packet D1 to root network node R, then the RWN with the 5th network node M5 responds flag set.

In the second more favourable flag set deformation program of the ratio first flag set deformation program of the inventive method, from the 5th network node M5 when root network node R sends packet D1 just to the RWN response flag set of the 5th network node M5.The second flag set deformation program is more favourable than the first flag set deformation program, because do not need to inquire about other condition, has alleviated the difficulty of implementing thus.

If the 5th network node M5 receives the routing inquiry message RAN that periodically sends from root network node R, then the 5th network node M5 will upgrade the data transfer path that the 5th network node M5 leads to root network node R thus with in the routing table of this RAN data designated transmission path typing the 5th network node M5 or rewrite present clauses and subclauses.If RWN response sign is set, then the 5th network node M5 also sends response message RWN to root network node R.Root network node R receives this RWN, will be with in the routing table of the data transfer path typing root network node R that leads to the 5th network node M5 of this RWN appointment or rewrite present clauses and subclauses, thereby set up or upgrade one-way data transmission path (reverse path), and between root network node and the 5th network node M5, set up bidirectional data transmission paths in this way from root network node to the five network node M5.

Root network node R periodically sends query messages RAN with broadcasting method to network node M1, M2 .., M7.This means that each network node M1, M2 .., M7 also can repeatedly obtain identical routing inquiry message, wherein each routing inquiry message specifies another to have the data transfer path that leads to root network node R of other path metric in case of necessity.By sign or sequence number, each network node M1, M2 .., M7 can distinguish the different routing inquiry message (RAN) that periodically sends from root network node R.

If the 5th network node M5 receives routing inquiry message RAN and RWN response sign from root network node R and is set, then the 5th network node M5 can send deformation program and immediately route response message RWN sent to root network node R according to a RWN of the inventive method.If the 5th network node M5 receives other routing inquiry message RAN with same sequence number or sign from root network node R, then the 5th network node M5 sends to root network node R with route response message RWN immediately at the RAN that each has the better path metric that leads to root network node R.This means always to send route response message RWN to root network node R, till the routing inquiry message that has better path metric up to not reentrying from the 5th network node M5.

If the 5th network node M5 receives the routing inquiry message RAN that periodically sends from root network node R, and RWN response sign is set, then the 5th network node M5 sends deformation program according to preferred the 2nd RWN of the inventive method, just sends route response message RWN to root network node R through the selectable stand-by period after receiving RAN.To all routing inquiry message RAN (having identical sequence number or the ID) analysis path that is received by the 5th network node M5 during waiting time tolerance, wherein the 5th network node M5 sends route response message RWN at the RAN with optimal path tolerance to root network node R.Reduced the 5th network node M5 also receives other RAN with better path metric (having identical sequence number or ID) after having sent route response message RWN probability thus, advantageously reduced the quantity of the route response message RWN that is sent thus and reduced data business volume.

Equally, receive the former of RAN thereby change and RWN response sign when being set for being different from data transfer path, can produce route response message RWN and send to root network node R by the 5th network node M5 equally from the 5th network node M5 to root network node R.This for example obtains failure message that the fault of the data link in the data transfer path is encoded or learns that by hardware checker adjacent data link is exactly this situation when breaking down at the 5th network node M5.

In order to remove RWN response sign, there are the various deformation programs that reset.

According to the first sign deformation program that resets, be right after sending RWN by the 5th network node M5 as after to the reaction that receives RAN, RWN response sign is reset to 0.If the 5th network node M5 does not send packet D1 being used for periodically being sent by root network node R in the time interval of RAN, then no longer respond the RAN that is received with RWN.Each packet D1 for sending during this time interval responds flag set with RWN again.

Indicate the deformation program that resets according to second, send RWN as after to the reaction that receives RAN through the selectable time interval, and before first packet D1 or before data transfer path changes, RWN response sign is reset to 0 by the 5th network node M5.At this, send packet D1 and will be used to measure the timer that time of this optional time interbody spacer changes again and reset to initial value to root network node R by each the 5th network node M5.At this, overtime initial value is greater than the time interval that is used for periodically being sent by root network node R RAN, and RAN has arrived the 5th network node M5 at RWN response sign when being set thus.

First sign resets deformation program towards the operation of Routing Protocol, and second sign deformation program that resets then designs according to data business volume.The reset advantage of deformation program of first sign do not need to be the timer that adds.Second indicates that the advantage of the deformation program that resets is and can implements very simply.

If the 5th network node M5 does not send packet D1 being used for periodically being sent by root network node R in the time interval of RAN, then no longer respond the RAN that is received with RWN.Each packet D1 for sending during this time interval responds flag set with RWN again.

The parameter of the RWN that is sent to root network node R by the 5th network node M5 is to be provided with according to the rule of HWMP or based on the RM-AODV/AODV of HWMP.Life-span among the RWN is set to be included in RAN or answers life-span among the formula PREQ earlier.

Referring now to Fig. 3, wherein explain embodiment in the communication network of Fig. 1 according to the inventive method with schematic diagram, realize that wherein first sign deformation program that resets responds sign with (removing) RWN that is used to reset.

In the figure of Fig. 3, the state of line segment " FL " expression RWN response sign, this state can be to remove (0) or set (1).Line segment M5 represents the 5th network node M5 as source network node.The arrow of sensing line segment M5 is represented the packet by the 5th network node M5 reception.Represent the packet that sends by the 5th network node M5 from the arrow of line segment M5.In Fig. 3, line segment FL and M5 distribute respectively from the top down, demonstrate time-varying process thus.Represent by alphabetical A-L in the various situations that are used for during the method for setting up bidirectional data transmission paths between the 5th network node M5 and the root network node R.

The RWN that the 5th network node M5 is not shown in Fig. 3 has sent sign.Sign of the RWN of the 5th network node M5 response in advance and RWN have sent sign and have been set to remove.

In situation " A ", the 5th network node M5 receives routing inquiry message RAN from root network node R, data transfer path that will appointment in this routing inquiry message is entered in the routing table of the 5th network node M5, or upgrade respective entries in the routing table of the 5th network node M5, so that set up one-way data transmission path thus, upgrade RAN and will send to next network node through the RAN that revises with very little time delay from the 5th network node M5 to root network node R.The RWN response sign of the 5th network node M5 still keeps removing.The RWN of the 5th network node M5 has sent sign and has still kept removing.

In situation " B ", the 5th network node M5 receives packet D2 from another network node as the second network node M2, and this packet D2 is passed to other network node.The RWN response sign of the 5th network node M5 still keeps removing.The RWN of the 5th network node M5 has sent sign and has still kept removing.

In situation " C ", the 5th network node M5 receives packet D2 from another network node as the second network node M2 again, and this packet D2 is passed to other network node.The RWN response sign of the 5th network node M5 still keeps removing.The RWN of the 5th network node M5 has sent sign and has still kept removing.

In situation " D ", the 5th network node M5 receives another (producing again) the query messages RAN have with the different sequence numbers of RAN of front from root network node R, upgrade the respective entries in the routing table of the 5th network node M5, so that set up the one-way data transmission path of renewal thus from the 5th network node M5 to root network node R, upgrade this RAN, and will send to next network node through the RAN that revises with very little time delay.The RWN response sign of the 5th network node M5 still keeps removing.The RWN of the 5th network node M5 has sent sign and has still kept removing.

In situation " E ", the 5th network node M5 receives packet D1 from more high-rise (S2), the layer on the wireless network compartment of mesh network just, network node is exchange data packets in this clathrum, and this packet D1 should send root network node R to by the 5th network node M5.This is not shown specifically in Fig. 3.

Also before sending packet D1 to root network node R, just also before sending first packet D1, the 5th network node M5 just produces response message RWN and sends to root network node R.Root network node R receives RWN, and the respective data transfer path that will lead to the 5th network node M5 is entered in the routing table of root network node R, setting up thus, and between the 5th network node M5 and root network node R, set up bidirectional data transmission paths in this way from the one-way data transmission path (reverse path) of root network node to the five network node M5.Simultaneously, the 5th network node M5 has sent flag set with its RWN.Then, the 5th network node M5 sends to root network node R with packet D1.The 5th network node M5 is with its RWN response flag set simultaneously.

In situation " F ", the 5th network node M5 receives another packet D1, and this is not shown specifically in Fig. 3, and this packet D1 is sent to root network node R.The RWN response sign of the 5th network node M5 still keeps set.The RWN of the 5th network node M5 has sent sign and has still kept set.

In situation " G ", the 5th network node M5 receives another packet D1, and this is not shown specifically in Fig. 3, and this packet D1 is sent to root network node R.The RWN response sign of the 5th network node M5 still keeps set.The RWN of the 5th network node M5 has sent sign and has still kept set.

In situation " H ", the 5th network node M5 receives another packet D1, and this is not shown specifically in Fig. 3, and this packet D1 is sent to root network node R.The RWN response sign of the 5th network node M5 still keeps set.The RWN of the 5th network node M5 has sent sign and has still kept set.

Then, the 5th network node M5 receives another (producing again) the routing inquiry message RAN have with the different sequence numbers of RAN of front from root network node R in situation " H ", upgrade the respective entries in the routing table of the 5th network node M5, so that set up the one-way data transmission path of renewal thus from the 5th network node M5 to root network node R, upgrade this RAN, and will send to next network node through the RAN that revises with very little time delay.In addition, the 5th network node M5 removes its RWN and has sent sign or allowed its set, because its RWN response sign is set.

Because the 5th network node M5 has received the query messages RAN that periodically sends from root network node R, and because RWN response sign is set, therefore the 5th network node M5 produces response message RWN and this response message is for example sent to root network node R with very little time delay.The 5th network node M5 has sent flag set with its RWN.Root network node R receives this RWN, and is overwritten in the routing table of root network node R and leads to the respective data transfer path of the 5th network node M5, so that upgrade thus from the one-way data transmission path (reverse path) of root network node R to the five network node M5.

By after receiving RAN and up to the time delay before root network node R transmission RWN, reduce the 5th network node M5 and after having sent route response message RWN, also received the probability that other has the RAN of better path metric (and having identical sequence number), thereby reduced the quantity of the RWN that sends to root network node R in this way.

According to indicating the deformation program that resets, remove RWN response sign along with the transmission of response message RWN at first of RWN response sign.

In situation " I ", the 5th network node M5 receives another packet D1 that is identified for root network node R, and this is not shown specifically in Fig. 3, and this packet D1 is sent to root network node R.The RWN response sign of the 5th network node M5 is set.The RWN of the 5th network node M5 has sent sign and has still kept set.

In situation " J ", the 5th network node M5 receives another packet D1, and this is not shown specifically in Fig. 3, and this packet D1 is sent to root network node R.The RWN response sign of the 5th network node M5 keeps set.The RWN of the 5th network node M5 has sent sign and has still kept set.

In situation " K ", the 5th network node M5 receives another (producing again) the routing inquiry message RAN with sequence number that the RAN with respect to the front changes from root network node R, upgrade the respective entries in the routing table of the 5th network node M5, so that set up the one-way data transmission path of renewal thus from the 5th network node M5 to root network node R, upgrade this RAN, and will send to next network node through the RAN that revises with very little time delay.In addition, the 5th network node M5 removes its RWN and has sent sign or allowed its set, because its RWN response sign is set.Because the 5th network node M5 receives the routing inquiry message RAN that periodically sends from root network node R, and because RWN response sign is set, therefore the 5th network node M5 produces route response message RWN and this RWN is for example sent to root network node R with very little time delay.Root network node R receives this RWN, and is overwritten in the routing table of root network node R and leads to the respective data transfer path of the 5th network node M5, so that upgrade thus from the one-way data transmission path (reverse path) of root network node R to the five network node M5.In addition, according to indicating the deformation program that resets, remove RWN response sign along with the transmission of response message RWN at first of RWN response sign.Along with the transmission of RWN RWN has been sent flag set.

In situation " L ", the 5th network node M5 receives another (producing again) the routing inquiry message RAN have with the different sequence numbers of RAN of front from root network node R, upgrade the respective entries in the routing table of the 5th network node M5, so that set up the one-way data transmission path of renewal thus from the 5th network node M5 to root network node R, upgrade this RAN, and will send to next network node through the RAN that revises with very little time delay.Though the 5th network node M5 receives the query messages RAN that periodically sends from root network node R, because RWN response sign is eliminated, the 5th network node M5 does not produce response message RWN, and does not send corresponding RWN to root network node R.Remove RWN along with the reception of RAN and sent sign.

Referring now to Fig. 4,, realize that wherein second sign resets deformation program to be used to the RWN response sign that resets wherein with schematic diagram explanation another embodiment in the communication network of Fig. 1 according to the inventive method.

In the figure of Fig. 4, be similar to Fig. 3, the state of line segment " FL " expression RWN response sign, line segment M5 represents the 5th network node M5.The time-varying process of the timer TI of downward counting is shown in addition, and this timer is used for the RWN response sign of the 5th network node M5 is resetted, and this timer TI count down to the concluding time 0 of the predeterminable time interval t that puts always from initial value t.This overtime initial value is greater than the time interval that is used for periodically sending by root network node R RAN, and RAN could arrive the 5th network node M5 at RWN response sign when being set thus.Represent by alphabetical A-L in the various situations that are used for during the method for setting up bidirectional data transmission paths between the 5th network node M5 and the root network node R.

The RWN that the 5th network node M5 is not shown in Fig. 4 has sent sign.At second sign of the RWN response sign that is used for the resetting deformation program that resets, can also use RWN response sign to replace RWN to send sign, be first packet (RWN response sign is eliminated) or other packet (RWN response sign is set) with specified data grouping D1.The sign of the RWN of the 5th network node M5 response in advance is set to remove.The RWN of the 5th network node M5 has sent sign and has been set to removing in advance.

In situation " A ", the 5th network node M5 receives query messages RAN from root network node R, data transfer path that will appointment in this query messages is entered in the routing table of the 5th network node M5, or upgrade respective entries in the routing table of the 5th network node M5, so that set up one-way data transmission path thus, upgrade RAN and will send to next network node through the RAN that revises with very little time delay from the 5th network node M5 to root network node R.The RWN response sign of the 5th network node M5 still keeps removing.The RWN of the 5th network node M5 has sent sign and has still kept removing.

In situation " D ", the 5th network node M5 receives another (producing again) the query messages RAN have with the different sequence numbers of RAN of front from root network node R, upgrade the respective entries in the routing table of the 5th network node M5, so that set up the one-way data transmission path of renewal thus from the 5th network node M5 to root network node R, upgrade this RAN, and for example will send to next network node through the RAN that revises with very little time delay.The RWN response sign of the 5th network node M5 still keeps removing.The RWN of the 5th network node M5 has sent sign and has still kept removing.

In situation " E ", the 5th network node M5 receives packet D1 from more high-rise (S2), the layer on the wireless network compartment of mesh network just, network node is exchange data packets in this clathrum, and this packet D1 should send root network node R to by the 5th network node M5.This is not shown specifically in Fig. 4.

Also before sending packet D1 to root network node R, just also before sending first packet D1, the 5th network node M5 just produces response message RWN and sends to root network node R.Root network node R receives RWN, and the respective data transfer path that will lead to the 5th network node M5 is entered in the routing table of root network node R, setting up thus, and between the 5th network node M5 and root network node R, set up bidirectional data transmission paths in this way from the one-way data transmission path (reverse path) of root network node to the five network node M5.Simultaneously, the 5th network node M5 has sent flag set with its RWN.Then, the 5th network node M5 sends to root network node R with packet D1, and its RWN response flag set is also started the timer TI with initial value t.

In situation " F ", the 5th network node M5 receives another packet D1, and this is not shown specifically in Fig. 4, and this packet D1 is sent to root network node R.The RWN response sign of the 5th network node M5 still keeps set.The RWN of the 5th network node M5 has sent sign and has still kept set.Timer TI is reset to initial value t and is activated again.

In situation " G ", the 5th network node M5 receives another packet D1, and this is not shown specifically in Fig. 4, and this packet D1 is sent to root network node R.The RWN response sign of the 5th network node M5 still keeps set.The RWN of the 5th network node M5 has sent sign and has still kept set.Timer TI is reset to initial value t and is activated again.

In situation " H ", the 5th network node M5 receives another packet D1, and this is not shown specifically in Fig. 4, and this packet D1 is sent to root network node R.The RWN response sign of the 5th network node M5 still keeps set.The RWN of the 5th network node M5 has sent sign and has still kept set.Timer TI is reset to initial value t and is activated again.

Then, the 5th network node M5 receives another (producing again) the routing inquiry message RAN have with the different sequence numbers of RAN of front from root network node R, upgrade the respective entries in the routing table of the 5th network node M5, so that set up the one-way data transmission path of renewal thus from the 5th network node M5 to root network node R, upgrade this RAN, and will send to next network node through the RAN that revises with very little time delay.The 5th network node M5 removes its RWN and has sent sign or allowed its set, because its RWN response sign is set.

Because the 5th network node M5 has received the query messages RAN that periodically sends from root network node R, and because RWN response sign is set, therefore the 5th network node M5 produces route response message RWN and this response message is for example sent to root network node R with very little time delay.The 5th network node M5 has sent flag set with its RWN.Root network node R receives this RWN, and is overwritten in the respective data transfer path of leading to the 5th network node M5 in its routing table, so that upgrade thus from the one-way data transmission path (reverse path) of root network node R to the five network node M5.According to indicating the deformation program that resets at second of RWN response sign, RWN response sign still keeps set.

In situation " I ", the 5th network node M5 receives another packet D1, and this is not shown specifically in Fig. 4, and this packet D1 is sent to root network node R.The RWN response sign of the 5th network node M5 still keeps set.The RWN of the 5th network node M5 has sent sign and has still kept set.Timer TI is reset to initial value t and is activated again.

In situation " J ", the 5th network node M5 receives another packet D1, and this is not shown specifically in Fig. 4, and this packet D1 is sent to root network node R.The RWN response sign of the 5th network node M5 keeps set.The RWN of the 5th network node M5 has sent sign and has still kept set.Timer TI is reset to initial value t and is activated again.

In situation " K ", the 5th network node M5 receives another (producing again) the routing inquiry message RAN have with the different sequence numbers of RAN of front from root network node R, upgrade the respective entries in the routing table of the 5th network node M5, so that set up the one-way data transmission path of renewal thus from the 5th network node M5 to root network node R, upgrade this RAN, and will send to next network node through the RAN that revises with for example very little time delay.In addition, the 5th network node M5 removes its RWN and has sent sign or allowed its set, because its RWN response sign is set.Because the 5th network node M5 receives the routing inquiry message RAN that periodically sends from root network node R, and be " 1 " because RWN response sign is set, therefore the 5th network node M5 produces route response message RWN and this RWN is for example sent to root network node R with very little time delay.Root network node R receives this RWN, and is overwritten in the respective data transfer path of leading to the 5th network node M5 in its routing table, so that upgrade thus from the one-way data transmission path (reverse path) of root network node R to the five network node M5.According to indicating the deformation program that resets at second of RWN response sign, RWN response sign still keeps set.RWN has sent sign and has been set.

In situation " L ", the time interval end of run of timer TI, the RWN response sign of the 5th network node M5 is eliminated.Then the 5th network node M5 receives another (producing again) the routing inquiry message RAN that has with the different sequence numbers of RAN of front from root network node R, upgrade the respective entries in the routing table of the 5th network node M5, so that set up the one-way data transmission path of renewal thus from the 5th network node M5 to root network node R, upgrade this RAN, and for example will send to next network node through the RAN that revises with very little time delay.Though the 5th network node M5 receives the routing inquiry message RAN that periodically sends from root network node R, because RWN response sign is eliminated, the 5th network node M5 does not produce response message RWN, and does not send corresponding RWN to root network node R.RWN has sent sign and has been eliminated.

Show the advantage of the inventive method (example 1) by sample calculation below with respect to conventional method, in conventional method, only before first packet D1, send route response message (comparative examples 1) to the root network node once, and with respect to the advantage of another kind of possibility method, in this another kind possibility method always in acquisition routing inquiry message (RAN) afterwards to root network node transmission route response message (comparative examples 2).

Adopt following abbreviation:

The quantity of N=network node

Path between H=network node and the root network node

The average path length of dH=from the all-network node to the root network node; DH 〉=1

T_g=t_gesamt: the time period of being investigated

T_d=t_daten: network node sends the time of data to the root network node as source network node

RAI=routing inquiry message (RAN) duration at interval

The quantity ara=((t_g/RAI)+1) of the routing inquiry message (RAN) that ara=started by the root network node during the time period of being investigated

Example 1

For example 1, what just have reaction equation (on demand) RWN answers formula RAN earlier, the quantity of RAN is given as: ara*N.

The quantity of RWN: ((t_d/RAI+1) * H.

The sum of route messages: ara*N+ ((t_d/RAI)+1) * H.

Comparative examples 1

The quantity of RAN: ara*N.

The quantity of RWN: H (before first packet D1).

The sum of route messages: ara*N+H.

Comparative examples 2

The quantity of RAN: ara*N.

The quantity of RWN: ara*N*dH.

The sum of route messages: ara*N* (1+dH).

Representative value for example is:

N＝30

H＝4

dH＝3

t_g＝900s

t_d＝300s

RAI＝5s

Produce following cost (sum of the route messages that is sent) at this:

(ara＝181)

Example 1:5674 route messages

Comparative examples 1:5431 route messages

Comparative examples 2:21720 route messages

Shown in this sample calculation, can significantly reduce the quantity of route messages by example 1 (method of the present invention), reduce 73.9% at this.

Other bright features of this law are provided by following description:

The general thoughts that the present invention improves non-logging mode comprises:

-always only at network node when the root network node sends packet D1 and this network node and is the source network node of this packet D1, this network node just responds RAN with RWN;

-RWN responds sign, and it determines that RWN whether should be as to the response of RAN and send.The OFF/0 meaning is not send RWN, and the ON/1 meaning is that RWN sends to the root network node in response when obtaining RAN;

-be used for different mechanisms to above-mentioned flag set and removing.

The principle rule is as follows: when condition was below set up, RWN sent to the root network node by network node:

[RWN responds sign=ON/1] and [[network node has obtained RAN] or [path of leading to the root network node changes]].

The mechanism of the inventive method is only carried out by the network node that source network node and this packet D1 as packet D1 are sent to root network node R.That is to say that these packets are from more high-rise these network nodes of coming, and these network nodes are first nodes of netted connection.Obtain packet D2 and this packet D2 is passed to the intermediate node of other network node according to its routing table, do not need to note the mechanism described in the methods of the invention for these packets D2.Especially, because these packets D2 does not send RWN to the root network node, RWN is not responded flag set yet.By method of the present invention, can be between network node and root network node during swap data, make the forward path that is used for transmission of data packets between network node and root network node and reverse path through identical network node.Forward path and reverse path are through best path.Can be by method of the present invention not only at forward path but also overcome the fault (link space) of data link at reverse path.Fault in the data link from root network node-to-network node reverse path no longer needs to overcome with bothersome AODV route recovery mechanism.

RWN response sign provides simple decision method, judges that promptly RWN whether should be as the response of RAN is sent.Be used for providing execution mode flexibly to the distinct methods that RWN response sign resets, for example adopt data grouping safety time afterwards in the end, in this safety time, still send RWN, and still keep reverse path thus from the root network node to this network node.By responding RAN, can also at reciprocal intermediate node, upgrade the variation of data transfer path with RWN.By additional improvement, promptly obtain the former of RAN thereby when changing for being different from data transfer path from network node to the root network node, also under the situation that RWN response sign is set, send RWN to the root network node, then the variation of forward path can pass to reverse path, thereby correspondingly upgrades reverse path.Use can cause forward path and reverse path to have the availability of equal length from the life-span of RAN or the life-span that is used as among the RWN that is sent from the life-span of answering formula PREQ earlier.

Claims

1. method of in wireless netted packet-switched communication networks network, setting up bidirectional data transmission paths, this communication network has a plurality of network nodes, and a network node is as the root network node, wherein in this communication network in these network nodes:

-answer formula ground to set up logical topology structure earlier with at least one routing tree form, wherein the root network node (R) of this routing tree sends to routing inquiry message (RAN) with the periodic time interval network node (M1-M7) of communication network, wherein this routing inquiry message is specified the first one-way data transmission path that leads to root network node (R)

-in the network node (M1-M7) of routing tree, set up the transmission that first sign that can be placed in two different conditions is controlled route response message (RWN) respectively,

If-the first sign is placed in selectable first state (ON), then network node (M5) sends to root network node (R) with route response message (RWN) when receiving routing inquiry message (RAN), wherein this route response message is specified the second one-way data transmission path that leads to this network node, between root network node (R) and this network node (M5), set up two-way data transfer path thus

If-the first sign is placed in second state, then network node does not send route response message.

2. method according to claim 1, if wherein a network node (M5) as communication network on the data transfer path that leads to root network node (R) first network node and obtain to send to the packet (D1) of root network node (R), then first sign with this network node (M5) places first state (ON).

3. method according to claim 1 and 2 wherein is right after first sign of a network node (M5) having sent route response message (RWN) to root network node (R) and places second state (OFF) afterwards.

4. according to each described method in the claim 1 to 3, wherein first sign with a network node (M5) just places second state (OFF) after selectable very first time interval elapses, this very first time at interval will be along with sending packet (D1) to the root network node and starting, this packet (D1) is that this network node (M5) obtains as first network node of communication network on the data transfer path that leads to the root network node, and the wherein said very first time all is reset to this initial value at interval of selectable very first time at interval when each this packet of transmission (D1).

5. according to each described method in the claim 1 to 4, if wherein network node (M5) obtains to be used to send to the packet (D1) of root network node as first network node of communication network on the data transfer path that leads to the root network node, and first network node on the data transfer path that is leading to root network node (R) in second time interval that is right after before receiving this packet as communication network does not obtain packet (D1) and will send to the root network node, and then this network node (M5) sends to root network node (R) with route response message (RWN).

6. method according to claim 5, if wherein be arranged on the transmission that is used to control route response message in the network node (M5), and can place second sign of two kinds of different conditions (ON/OFF) to be placed in selectable first state (O), then this network node (M5) sends route response message (RWN) to root network node (R).

7. method according to claim 6 wherein indicates that with second of network node (M1-M7) setting in advance is second state (OFF) when beginning the communication network initialization.

8. according to each described method in the claim 1 to 7, if wherein a network node (M5) sends route response message (RWN) to root network node (R) before in first packet (D1) that sends data communication to root network node (R), then first sign with this network node (M5) places first state (ON).

9. according to each described method in the claim 1 to 8, wherein directly receiving routing inquiry message (RAN) afterwards to root network node (R) transmission route response message (RWN).

10. according to each described method in the claim 1 to 8, wherein after receiving routing inquiry message (RAN), postpone to send route response message (RWN) to root network node (R) through the regular hour.

11., wherein when beginning, first of network node (M1-M7) is indicated that setting in advance is second state (OFF) to the communication network initialization according to each described method in the claim 1 to 10.

12. according to each described method in the claim 1 to 11, wherein to the life parameter of the route response message (RWN) of the life-span coding of the second one-way data transmission path of leading to network node be set to be included in the routing inquiry message (RAN) of reception, to the life parameter of the life-span coding of the first one-way data transmission path that leads to root network node (R).

13. according to each described method in the claim 1 to 12, this method is based on mixing Routing Protocol HWMP.

14. one kind especially according to each described method of setting up bidirectional data transmission paths in wireless mesh packet-switched communication networks network in the claim 1 to 13, this communication network has a plurality of network nodes, one of them network node is as the root network node, wherein in this communication network:

-answer formula ground to set up logical topology structure earlier with at least one routing tree form, wherein the root network node of this routing tree sends to routing inquiry message (RAN) with the periodic time interval network node (M1-M7) of communication network, wherein this routing inquiry message is specified the first one-way data transmission path that leads to root network node (R)

If-the first sign is placed in selectable first state (ON), then network node (M5) sends to root network node (R) with route response message (RWN) when detecting the first one-way data transmission path variation of leading to root network node (R), wherein this route response message is specified the second one-way data transmission path that leads to this network node, between root network node (R) and this network node (M5), set up two-way data transfer path thus

15. a wireless mesh packet-switched communication networks network is provided for carrying out the network node (M1-M7) according to each described method in the claim 1 to 14 in this communication network.

16. be used for computer-readable program code according to the network node (M1-M7) of the described communication network of claim 15, this computer-readable program code comprises control command, and this control command impels this network node to carry out according to each described method in the claim 1 to 14.

17. the network node according to the described communication network of claim 15 (M1-M7) is implemented computer-readable program code according to claim 16 on this network node.

18. a storage medium has the computer-readable program code according to claim 16 that is stored on this storage medium.