ISSN (Online): 2348 – 3539.
Dynamic Router Selection based on the Mobile Tracking in Mesh
Networks
1
M.Krishnakumar,
2S.Balakumar
1PG Scholar, Department of Electronics and Communication Engineering, K.S.Rangasamy College of Technology, Tiruchengode.
2
Assistant Professor, Department of Electronics and Communication Engineering, K.S.Rangasamy College of Technology, Tiruchengode.
Abstract: A Mobile adhoc network (MANET) consists of mobile wireless nodes. MANET is a selfcreating, self-organizing and self-administering wireless network of mobile router (and associated hosts). The communication between these mobile nodes is carried out without any centralized control. Now-a-day’s MANETs may endure from network partitioning. This restriction makes MANETs unsuitable for applications such as crisis (situation) management and battlefield communications, in which team members might need to work - groups scattered in the application terrain. To address this impuissance, a new category of ad-hoc network had been introduced that is called Autonomous Mobile Mesh Network (AMMNET). IMAMMNET (Improved AMMNET) is a proposed scheme that certainly helps the wireless mobile router/ clients to easily search the best neighboring routers. Consequently, clients can be serviced with minimized data frame losses while they are performing the handoff method. For practical implementation of performance parameters can be evaluated by comparing the Packet Losses, Throughput, Mesh Router Required, Message Overhead, Hopcount, Total Covered Clients between the proposed handoff scheme and the existing method (AMMNET). Based on the evaluation, an analytical model is build to estimate the overall improvement when a client moves from one router to another router in an indoor environment.
Keywords: —Mobile mesh networks, client mobility, dynamic topology, client tracking, Handoff
Reference to this paper should be made as follows: 1M.Krishnakumar,2S.Balakumar (2015) ‘Dynamic Router Selection based on the Mobile Tracking in Mesh Networks’, International Journal of Inventions in Computer Science and Engineering, Volume 2 Issue 4 2015.
1 Introduction
Wireless technology has been one of the most empowerment technologies in recent days. Especially, the MANET is related to the wireless adhoc network in which the nodes can move freely and it can transmit and receive the traffic. Here the network infrastructure is not available and also there is no restriction to join or leave the nodes from the network. The mobile nodes can able to act as a router to forward data packets to their destinations through multiple relay. The network topology [14] may change rapidly according to the situation. However, it cannot be flexible for the topology adaptation function. To deal this challenging problem, proposed a new class of mobile ad hoc network called Autonomous Mobile Mesh Networks (AMMNET). The mesh client’s mobility is limited to the fixed area by a standard form of wireless mesh network. The mobile clients can move with their group functionality routers and it can be adapted to the dynamic network topology. The predeployment of mesh network is not possible for much temporary application such as disaster relief areas, military rescue operations etc…
A.
AMMNET
AMMNET (Autonomous Mobile Mesh Network) is a good nominee, because it can adapt for the dynamic environment. AMMNET [15] is not enough to support the number of mesh nodes in the entire application terrain. The data delivery probability can be improved by Delay Tolerant Network (DTN) [3]. Each and every mobile mesh node is furnished with fixed devices such as GPS (Global positioning System). The mobile mesh node detects the mesh client within its sensing range but it does not know the accurate location. For this, the mesh client periodically broadcast the beacon message for the particular instance of time. In others, RFID (Radio Frequency Identifier) [4] is a reader to detect the mobile nodes presence within its sensing range.
II. Distributed Client Tracking In
AMMNETA.
AMMNET overview
AMMNET is a mesh infrastructure network. Mobile clients connect via nearby nodes to reach the destination via multihop forwarding. The routers in the AMMNET are mobile platforms with independent movement capability. They are furnished with setting devices such as GPS. All the mobile clients will periodically broadcast the beacon message to notify the presence within the network. Once the mesh nodes receive the beacon message means only it knows that the clients are within its sensing range. By using this, the mesh nodes continuously monitor the group mobility [5] of the clients. The group mobility model has been verified as a realistic mobility model [6] and applied to many practical scenarios, such as campus networks [7] and ad hoc networks [8], [9]. The main aim is to allocate the finite number of mesh nodes dynamically to cover large set of mobile clients at the time of maintaining the client groups connectivity. Thus the AMMNET supported for the dynamic connectivity of independent clients. For this support, there are three classified function in the network.
Intragroup routers:
A mesh node is an intragroup router if it detect within the radio range and also supervising the same group of clients can communicate with each other via multihop routing.
Intergroup routers:
A mesh node is an intergroup router if it interconnects different groups in the network and also intergroup router can communicate to any intergroup routers.
Free router:
Free router consists of neither it is an intragroup nor an intergroup router. Initially AMMNET consists of one intragroup router only. While tracking the mobile clients, the mesh mode change their operation based on distributed client tracking for router. In terms of network security, standard mesh network are applicable in the proposed AMMNET [10].
B.
Accommodating to intragroup movement
Client continuously broadcast beacon message to notify its presence within the radio range of an intragroup router. If router no longer hears the expected beacon message means, two possible scenarios will be happened. The first scenario consists of client c moves out of the radio range, r into the communicate range of adjacent router r’ in Fig. 2 (i). Missing clients, c not covered by any of routers in the group of neighbor routers provide the coverage for c. Topology adaptation is required to extent the coverage to include c at its new location in Fig. 2 (ii). Once router r detects the missing client, it broadcast a message to trigger the neighbor free router to track the missing client c. client c moves out from the radio range of router r, a free router must be able to locate the client by navigating the boundary of r’s coverage. It reduces the disconnection time for a missing client. Boundary of the each active router is divided into k segment. Where k must be minimum of 12. The ratio of free router should be 1:12. The number of k free routers is available to search the missing client. Free routers are equally circulated among the active routers to check good functioning at all client groups in the terrain.
C.
Recovering extra router
Intragroup and intergroup router are repeated. Router r request client list of the neighbor intragroup router. If r observe that all its clients are covered by neighbor routers, it send message to clients for the switch operation mode. After get the ACK from the all neighbor r move to intergroup router.
D.
Interlinking groups
Clients of a group may divide into smaller groups that move in different directions. In this case, some free routers should change their operation mode to become intergroup routers to interlink these partitioned groups. The clients are moving aside from the reporting area, in different direction. Two clients of this group move out of the initial coverage area, a free router connects the network as a new intragroup router to provide coverage for these two clients.
to move further away from G1, the above process repeats and more intragroup routers in G2 become intergroup routers. Bridging network connect to interlink group G2, G3 and G4 their original group G1. These bridging networks maintain the connectivity for all clients and prevent network partition. After interconnecting all the groups, free routers can be redistributed such that all the partitioned groups have a similar number of free routers to improve tracking efficiency. After redeployment, each free router sends its recognition to the bridge routers in its group, and hence, any bridge router can track the number of free routers in its group.
III. Topology Adaptation
The protocol talked about so far checks that the mesh nodes preserve the connectivity for all clients. The resulting networks, still, may get long end-to-end delay with potentially many unneeded intergroup routers because the bridging networks are built independently.
As the example demonstrated in Fig. 4, if a client in group G2 wants to communicate with another client in group G3, this must be done through a long path over the router b1 at group G1 although groups G2 and G3 are near each other. Another potential drawback is the excessive use of the intergroup routers. To improve this consideration, two topology adaptation schemes were used namely local adaptation and global adaptation, each with a different resolution of location information to shorten the relay paths among groups.
A. Local adaptation
To preserve intergroup routers three independent bridging networks can substitute with a star network as demonstrated in Fig.5. A star topology generally provides shorter relay paths, and, as a result, expects more some intergroup routers. Specifically, when clients in dissimilar groups are communicating with each other, the corresponding bridge routers can replace their location information by piggy backing such information in the data packets. For instance, when client c1 transmits a data packet to client c2 through the bridge routers b2, b1, and b4. When this data packet gets at the bridge router b4, it can extract
the location information of b2 and b1 before forwarding the data packet. Likewise, the bridge router b1 can extract the location information of b2 from the data packet. After a bridge router has collected the local location information, it notices that bridge routers b2, b3, and it are settled near each other. This suggests that the corresponding groups G2, G3, and G4 are within proximity. To interconnect them by more effectively using a star topology, the bridge router b4 can act as the coordinating bridge router or organizer to trigger local topology adaptation. The organizer also requires to check the new built star topology which will be linked to the remaining of AMMNET. The organizer broadcast a message to find a bridge router not a part of the new network.
The bridging over networks between b2 and b1 and between b3 and b1 can be rejected, and their intergroup routers used for the new star network. Since the organizing bridge router b4 knows about these intergroup routers, it can make an assignment list to assign them to distinct data forwarding positions in the star network.When a bridge router receives a request with a smaller time stamp than that of the adaptation the router is presently involved with, it cancel its current adaptation process and follows the new one with a smaller time stamp. In terms of organizing the intergroup routers, a threeway handshake protocol is utilized. After an organizing bridge router sends out its assignment list, it waits for the intergroup routers to confirm. If all agree to participate, the organizer sends them a notification to continue with the topology adaptation otherwise, the organizer cancels the adaptation
B.
Global adaptation
number of mobile routers required and to deliver less endto-end delay time for the application.
Hierarchical star topology technique are based on R-tree function. The R-Tree is a multidimensional tree structure that consists of minimum boundary rectangle of object M. The larger boundary rectangle can be organized by the high level of M object in tree structure. The clustering process is repeated recursively to determine the hierarchical star topology. By applying k- means clustering [11] to find the suitable value for M. Hierarchical clustering is applied to the AMMNET for the star network deployment of R-Tree [12]. Multiple R-Trees can be deployed to form the star topology in the hierarchical star topology. The desired number of boundary rectangle M is 3. Fig.6. has shown the R-Tree construction. The star network of rectangle a interconnect the bridge router b1, b2 and b3. Similarly, the rectangle for b and c are constructed. The three star network of rectangle a, b and c are interconnect to form the rectangle d. To reduce the number of intergroup router by two strategy. First, do not build star network for the bridge router which are already interconnect in R-Tree. Likewise, the b1, b2, b3 bridge router are not connected in the star network. Next, if the client groups consist of multiple bridges router means they take only one bridge router to interconnect with star network. The multiple bridge routers in the same group are freed for the future use. Likewise, the bridge router b5 and b6 in rectangle b are present in group G4. So the b6 is freed for future use, before connecting b4 and b5 in star topology. By this, the global adaptation is achieved better end- to-end delay and less intergroup router usage.
The global adaptation is activated only due to the lack of available free routers. The number of free router drops below the predefined threshold value and then the corresponding bridge router acts as a coordinate and broadcast a message to the entire bridge router to initiate global adaptation. Any bridge router receives this broadcast message means it replies its location and the available free routers. When the coordinator receives positive replies from the entire bridge router, it proceeds to start the adaptation process.
IV. Improving Handoff Schemes Between Mobile
Mesh Routers In AMMNET
A seamless handoff scheme should be engaged for a better service. Handoff/ Handover refer to the process of transferring an ongoing call from one router to another router. In a proposed handoff scheme [16], the 802.11 routers have multiple radios is exclusively reserved for scanning purpose and it helps to easily search the best neighboring router. For practical application, handoff performance has been evaluated by comparing the packet loss between proposed handoff schemes (IMAMMNET) and the existing scheme (AMMNET). Based on the network performance, other parameters in the existing scheme are improved while a client moves from one router to another router in the mobile adhoc network. The proposed handoff operation consists of three procedures 1) scanning 2) authentication 3) reassociation. The 802.11 scanning is a procedure for clients to search neighboring routers. The scanning clients may choose the best appropriate AP among scanned APs for its handoff. The authentication and reassociation procedures are used for the validation and the connection establishment for the scanning clients.
V. Evaluation
The simulation is done via NS2, thus the performance evaluation have compared the following network strategies:
Grid-mesh: The mobile mesh network follows the users by
tracking only one randomly selected client. The network preserves the same grid topology as it moves over the application terrain. Specifically, WiMAX [1] and LTE [2] might be able to support broadband access for a given
AMMNET: This is the own design experience of
AMMNET, in which routers adapt their locations using only locally cached location information about some of the bridge routers. Global adaptation is also performed when the number of free routers at some user groups drops below a predefined threshold.
Global-AMMNET: Global-AMMNET is similar to the
above AMMNET, except that global adaptation is performed by a randomly selected bridge router whenever any client moves out of the current network coverage area.
Oracle: A centralized scheme that assumes location
information of all clients is available. The routers can move to the assigned locations in the network instantaneously without any moving delay
IMAMMNET: It is a proposed scheme that certainly helps
This scheme is only used as a bound for the purpose of performance comparison. Unlike AMMNET that uses the locations of the bridge routers to approximate the distribution of the user groups in the application terrain and constructs the R-tree based on these routers accordingly, Oracle constructs the R-tree using the exact locations of the mobile users. When there is not enough available routers to provide full connectivity for all the clients, this scheme favors the user groups (R-tree nodes) with a higher density of clients. The group leader move in accorandane to the random mobility with a moving speed that is uniformly distributed with a mean of 5m/s and also the group members follow the router with their own random movement. IMAMMNET consist of assumption done for the random group communication. In each time slot, four groups are randomly selected to transmit the UDP (User Datagram Protocol) traffic. The simulation results shown below are averaged over 1000 simulation runs.
A.
Performance of Network Coverage
The performances of the network coverage under different network scenarios are explained below:
Impact of Router Moving Speed
The number of available mesh nodes is not enough to cover all the clients in the simulation terrain. In the network terrain, there are 27 mesh nodes are deployed for the simulation and they are classified into five groups. The moving speed of router varies from the mean speed of clients to six times of the mean speed of clients. More number of routers are required to provide the communication coverage for the entire terrain. Otherwise the coverage will be decreased. AMMNET tracking the missing clients continuously, if it fails to track some missing clients means the number of covered clients will be reduced. Free router need to move fast to cover the network boundary region.
Coverage Area given a Finite Number of Router
Different comparison schemes for the same simulation setting to achieve the coverage area. Initially the group 1 is fixed and after it can be varies as 2, 3 and 4. Fig. 15 shows that AMMNET is able to achieve high covered user comparable to another 3 parameters.
Number of Router Required to Provide Entire Network Coverage
Assume that clients in the network classifying into four group. Fig .14 shows the AMMNET requires more routers to cover all clients in the network. All other parameters maintain a fixed topology and many routers in the network are wasted without any clients. Global adaptation performed in the AMMNET does not reclaim all redundant intergroup routers. Therefore AMMNET require
more routers to cover entire network. AMMNET is scalable with increase in the number of mesh clients if clients are partitioned into a limited number of groups. AMMNET framework supported for the large dynamic number of mobile users, if they are partitioned into only a few number of groups.
Impact of mobility pattern on network coverage
The communication coverage for 27 clients are separated into different numbers of groups. Figs 14 and 15 shows number of clients within the coverage area and number of router used to provide the coverage for the entire network. By continuously tracking mobile clients in the network, AMMNET can adapt to dynamic topology to connect all the clients in the network. By partitioning the clients into small groups, the number of router required to connect the clients will be increased. Each router forwards data at the transmission bit-rate of 11mb/s. From the total number of clients, some of the clients are randomly select four pairs of nodes to transmit UDP flows in the network.
System overhead
The dynamic network adaptation is performed by collecting location information of bridge router and multicast the location to the selected intergroup routers. Fig. 11 shows the average number of message exchange with the average moving speed. Fig. 12 shows the average number of message with number of groups i.e., the number of intergroup router along the bridging networks. Oracle requires a high message overhead to collect location information from all routers to track mobile clients. Global – AMMNET requires a few more message overhead than AMMNET because Global- AMMNET needs to verify all the bridge routers for their location information.
V. Results And Discussion
The analysis of the work is carried out in the Network Simulator2 under Linux Platform for analyzing the adaptive function between the group communications.
A.
Performance parameters
There are different kinds of parameters for the performance evaluation of the routing protocols. These have different behaviors of the overall network performance.
Throughput
The graph in Fig 7 is drawn between the average throughput and the traffic. From this comparison, IMAMMNET provides high throughput.
The graph in Fig 8 is drawn between the average throughput and the average moving speed. From this comparison, IMAMMNET provides high throughput.
Hopcount
Hops count refer to the number of nodes through which a data packet passes from source to the destination network.
The graph in Fig 9 is drawn between the average hopcount and the traffic. From this comparison, IMAMMNET provides less hopcount.
The graph in Fig 10 is drawn between the average hopcount and the average moving speed. From this comparison, IMAMMNET provides less hopcount.
B.
Number of message exchange
The graph in Fig 11 is drawn between the number of message exchange and the average moving speed. From this comparison, IMAMMNET provides less number of message exchanges overhead.
The graph in Fig 12 is drawn between the average message exchange and number of groups. From this comparison, IMAMMNET provides less number of message exchanges overhead.
The graph in Fig 13 is drawn between the average message exchange and number of traffic pairs. From this comparison, IMAMMNET provides less number of message exchanges overhead.
The in Fig 15 graph is drawn between the number of lost packets and number of traffic pairs. From this comparison, IMAMMNET provides less number of packet loss.
The graph in Fig 16 is drawn between the number of lost packets and number of traffic pairs. From this comparison, IMAMMNET provides less number of packet loss.
VI. Conclusion
AMMNET used for applications such as crisis management and battlefield communication, the mobile users need to work in dynamic formed groups that occupy different parts of a large and uncertain application terrain at different times. There is currently no cost-effective solution for such applications. Since the user groups occupy only a small portion of the terrain at any one time, it is not justifiable to deploy an expensive infrastructure to provide network coverage for the entire application terrain at all time. Unlike conventional mobile ad hoc networks, which suffer a problem during network partitions when the user groups move apart, the mobile mesh routers of an AMMNET track the users and dynamically adapt the network topology to seamlessly support both their intragroup and intergroup communications. Since this mobile infrastructure follows the users, full connectivity can be achieved without the need for high cost of providing
network coverage for the entire application terrain at all time as in traditional stationary infrastructure. The proposed schemes show an overall improvement when a client moves from one router to another router in mobile adhoc network.
Acknowledgments
This work was supported by CWIN in K.S.Rangasamy College of Technology. The author would appreciate the comments from the anonymous reviewers for Improving This Paper.
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Krishnakumar M was born in Erode, Tamilnadu, India in 1992. He received the B.E degree in Electronics and Communication Engineering from V.S.B engineering college, karur, India in 2013, the M.E degree in Applied
Electronics from
K.S.Rangasamy college of Technology, Tiruchengode, Namakkal district, India in 2015. His current interests include Mobile adhoc Networks, Wireless Sensor Networks and Information Security.
Balakumar S is an Assistant Professor of Electronics and Communication Engineering at K.S.Rangasamy College of Technology, Namakkal, India. He received the B.E degree in Electronics and Communication Engineering from Mahendra Engineering College, Namakkal, India, the M.E degree in VLSI
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