Comparative Study of Demand Driven Routing ...

Proceedings of the 13th WSEAS International Conference on COMMUNICATIONS

Comparative Study of Demand Driven Routing Protocols over Mobile Ad-hoc Networks G. E. RIZOS University of Peloponnese Department of Computer Science and Technology GR-221 00 Tripolis GREECE [email protected] ATEI of Epirus GR-471 00 Arta GREECE [email protected]

D. C. VASILIADIS University of Peloponnese Department of Computer Science and Technology GR-221 00 Tripolis GREECE [email protected] ATEI of Epirus GR-471 00 Arta GREECE [email protected]

E. STERGIOU ATEI of Epirus GR-471 00 Arta GREECE [email protected]

Abstract: In this paper, we present a comparative study in a MANET environment. MANET is specifically characterized by high mobility of network nodes and frequent changes of direct visibility. High dynamicity affects the design and implementation of distributed applications by significantly increasing their complexity, to consider not only routing and node configuration issues, but also the possible mobility of software components and the loss of direct connectivity during service provisioning. In this work, we estimate and compare the performance of on demand driven routing protocols (reactive) - Guided at requirement (counteractive) for ad-hoc networks. We use the file transfer protocol to measure the performance of our model. The protocol provides file downloading from a dynamically discovered service component available in a MANET locality, even if the server moves during file transfer. Key words Mobile Ad Hoc Networks (MANET), Routing Protocols, AODV, DSR, SSR, ABR, TORA, CBRP.

that the nodes of networks play active role in the routing of parcels, promoting apart from their own parcels and the parcels of neighbouring nodes. This characteristic is useful in cases where the sender and the recipient of parcel are not only found inside the beam the one of other (or the likely one from the two is found inside the beam of other). The terminals in an ad hoc network can function not only as end systems (they send information as senders and receive as recipients), but also as intermediary systems (they promote parcels of other nodes). Consequently it is feasible two nodes can communicate even in the case where the one is not found in the beam of transmission of other using them intermediary nodes as routers. This is also the reason that the wireless ad hoc networks are also known as multi-hop wireless networks [8]. The desirable result ad hoc networking is the strongly support and efficient operations in mobile networks through the benefit of services of routing in mobile nodes. Networks of this type are expected to have dynamic, dynamically altered, topologies that will be composed from wireless bonds that will have restrictions, however, for reasons of limited breadth of area. Ad hoc mobile

1. Introduction The wireless ad hoc networks as we reported and more are constituted by nodes (stations) that they are connected dynamically from each other. Main characteristic them it is that they are shaped by appliances that are capable to communicate from each other using a wireless natural means, without they require the existence of somebody of pre-existing network infrastructure[1,2]. These networks, that are also known as MANET (Mobile Ad hoc Networks), can function or autonomously shaping groups from wireless appliances, or some bodies from these wireless appliances be connected in some other constant network or even in Internet. This is also the reason that the ad hoc networks are suitable for environments where the operation of some other type of network is practically impossible. Besides, fundamental characteristic the ad hoc networks it is that they have the possibility of be shaped on-the-fly without the mediation of one central administration, consequently each node it is in position of transmitting at will in any desirable destination it selects. Basic characteristic the ad hoc networks it is

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topology of network, that automatically will cancel him because henceforth it will not be in effect [6]. This type of routing creates paths only when it is desirable from the node of source. When the node requires a street for the destination, commences a process of finding of street in t o network. This activity is completed as soon as is found a way or has been examined the all likely combinations of streets. When is discovered and installed a way, it is maintained with the help of type of process of maintenance of street up to that the destination is rendered not accessible by any path or by the source, or way it is not more desirable. Five protocols exist under the category [9]. Examples of reactive protocols include the Ad hoc On Demand Distance Vector (AODV) [5], the Dynamic Source Routing (DSR)[4], the Signal Stability Routing (SSR), the Temporally Ordered Routing Algorithm (TORA), the Associativity Based Routing (ABR) and the Cluster Based Routing Protocol (CBRP).

network it constitutes collection from mobile nodes that are placed dynamically and arbitrarily so that the between the nodes interconnections can are altered in continuous base. So that is facilitated the communication inside the network, a protocol of routing (routing protocol) is used in order to it discovers passages between the nodes. Fundamental objective of protocols of this type is the right and efficient establishment of tolls between a pair of nodes in order that the messages can be transmitted in time convenient. The clarification of routings will be supposed to become with the lower possible use and tax of network and breadth of area. The rest of the paper is organized as follows. In section 2 an overview of routing protocols for Ad Hoc Networks is presented. Section 3 presents the network model and section 4 performance analysis results. Finally, in section 5 conclusions are drawn.

2. Routing Protocols for Ad Hoc Networks

2.1.1 Ad Hoc On-Demand Distance Vector Routing (AODV)

In this piece we will analyze the protocols of routing that exist for the category of networks that we examine, the MANET. We distinguished three basic categories of protocols: o Table - driven o Demand - driven o Hybrid Table - Driven Routing Protocols (proactive) Guided from table of routing (dynamic): In this category of protocols the nodes that constitute the network allocate tables which contain elements for the routing of messages in any other node, and which are informed permanently for each change in the topology of network. Despite the make that the finding of new right path becomes enough fast, the permanent briefing of tables has as resulting from this protocols they cannot support very successfully, high mobility in the network Examples of proactive protocols include the Destination Sequence Distance Vector (DSDV) [3], the Fisheye State Routing (FSR), the Global State Routing (GSR), the Wireless Routing Protocol (WRP), the Clusterhead Gateway Switch Routing (CGSR) and the STAR. On Demand - Driven Protocols (reactive) Guided at requirement (counteractive): In the particular protocols are not maintained the all ways of each node in tables. On the contrary when exists application for mission of some message, the sender calls a algorithm for the finding of suitable path, which is maintained until the message reaches in his destination, or until is created such change in the

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AODV is a protocol of routing that is supported in protocol DSDV, but has been drawn specifically for the mobile ad-hoc networks. In the AODV, each node maintains table of routing that is used in order to it stores the destination and the next addresses of stations (IP) as well as the numbers of sequence of destination. Each entry in the table of routing have a address of destination, a next station, a list of nodes that will be followed, a duration of life, and a distance from the destination. In order to moves a process of discoveries of corridors one node it creates a parcel of demand of corridors (PREQ). The parcel contains address IP of node of source as well as address IP of destination [10, 11]. Advantages: it effectively uses the breadth of area (with the minimisation of charge of networks for the circulation of control and elements) it corresponds in the changes in the topology, is evolutionary and ensures free routing of loops. Disadvantages: the nodes use the crypts of routing in order to them answer in the questions of corridors. This leads to the unverifiable “answers” and to the repeated readjustments of crypts of nodes.

2.1.2 Dynamic Source Routing (DSR) It is a protocol of routing of source. Each node maintains crypt of corridors that contains the all sources of corridors that it knows. The node informs the registrations in the crypt of corridors when it

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error in the source that it determines who channel has failed. The source sends then a message in order to it informs the all nodes for the broken connection and moves a new process of search-way in order to it finds a new course in the destination.

learns for new ways. The DSR requires each parcel it keeps his information of paths, eliminating in consequence the need for each node in the network to make periodical emissions of discoveries of paths in other nodes [7]. The two important phases of protocol are: o Discovery of paths o Maintenance of paths Disadvantages: The parcels are transmitted at length of older paths. The DSR suffers also from a problem of scalability because in the nature of routing of source. Since the network grows the parcels of control and the parcels of messages they become also bigger. This gives a negative impact because limited breadth of area.

2.1.4 Temporally Ordered Routing Algorithm (TORA) It belongs in the family of algorithms of routing of inversion of contacts. It is adoptive and particularly evolutionary protocol of routing. It has as aim to minimise the reaction in the topology changes. The messages of control TORA are located in a very small total of nodes near to incident of topological change. In order to they achieve this; the nodes maintain the information of routing on the nodes in question (stations with direct communication). The TORA discovers fast the multiple ways after the requirement. The way it is not essential to be most optimal, but it guarantees that the all ways they are free. Advantages: It provides which free courses of bronchuses each moment. It provides multiple ways so if a course is not available, other is easily available. It establishes the ways fast so they can they are used before the changes of topology. It as generally speaking minimises the algorithmic reactions the expenses of communication and it maintains thus the available breadth of area and it increases the adaptability, he is also capable to detect the partitions of networks very fast. Disadvantages: As long as it grows the network is presented behaviour of instability, with the problem of numeration (0) INFINITY in the protocols of distance routing.

2.1.3 Signal Stability Routing (SSR) It is a protocol of routing that selects ways based on the force of channels between the nodes and on the stability of place of one node. The SSR includes two protocols that collaborate from each other: the dynamic protocol of routing (DRP) and the static protocol of routing (SRP). To DRP maintains the table of stability of signals (Signal Stability Table (SST)) and the table of routing (Routing Table (RT)). The SST stores the force of signals of neighbouring nodes that is received by the radio signals from the layer of connections of each neighbouring node. Proportionally the force of signals each channel is recorded as powerful or impossible. The all transmissions are received from DRP and process. After informs suitably the table of registrations, the DRP it grants the parcel in the SRP. The SRP promotes the parcel, if it locates the intended receptor. If no, is re-examined the destination in the RT and is promoted the parcel. If does not exist no entry for the destination in the RT, is moved a process of search-way in order to is found a way. The parcels of demand-way are only transmitted in the next station if they are received by powerful channels and have not been submitted in treatment previously (for reject of repetition). The destination takes the first parcel of search-way that reaches in order to it answers as it is particularly likely that the parcel reached beyond the shorter and/or less satiation course. The DRP reverses the selected way and sends a message of acceptance of way. The DPR of nodes at length of course informs the table of routing (RTs) proportionally. The parcels of search-way that reach in the destination have reached sure from the channel with the most powerful signal because the parcels that reach beyond a impossible channel fall in the intermediary nodes. When a failure of connections is detected in t o network, the intermediary nodes send a message of

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2.1.5 Associativity Based Routing (ABR) In ABR, a way is selected based on the situations of associative nodes. All nodes produce the radio signals in order to declare their existence. When one node of neighbours receives a signal, informs his routing tables. For each signal that it receives each node records in this table information on the node from which it received the signal. A high value of tick associativity with regard to one node shows a low situation of mobility of nodes, while a low value of tick associativity can show a high situation of mobility of nodes. The associativity rerouting when it moves neighbours of one node or the same node in which he belongs. Fundamental objective ABR is are found the distant existing ways for the ad hoc mobile networks.

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2.1.6 Cluster Based Routing Protocol (CBRP) According to their Jiang et al (1999) in the protocols cluster based the nodes of network are separated in teams-clusters. Cluster protocols based the routing is realised with her utilisation routing of shorter way. That is to say, receiving a demand of routing, the node tries it finds the most near node in the way and it sends the parcel in this node, contributing in this way in the reduction of way. At the promotion of parcel, if one node observes the existence of broken connection, it sends a message of fault in the source and afterwards it uses a mechanism of local repair of connection. According to this mechanism, when one node finds that the next node cannot be located, it checks in order to sees if the next node can be located via one of his neighbours. If functions one from the two ways, the parcel will be sent via the corrected path.

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Fig.1. Client can download the file directly from a local server (a) in response to server movements (b); clients continue the file download transparently via the locally elected proxy (c, d, e and f).

2.1.7 RDMAR This type router calculates the distance in the [radio] bronchus’s, between two nodes using the relative algorithm of estimate of distance and it uses the numbers of sequence in order to it maintains the freedom of bronchus’s at the duration of process of discoveries of corridors. A basic significance behind the RDMAR is the approach of maintenance of active courses (process maintenance of corridors). The algorithm of maintenance of corridors in RMDAR is a distributed operation that exploits the territorial relation of nodes when is presented a failure at length of active way and depending on the relative distance of node, that routes the failure from the call in other nodes, exists two cases: Is checked the most near way from the point that was observed the problem. Then RDMAR is to be applied in order to it locates the node that caused the failed way in the network. The node informs by calling previous node for the failure is delivered the call via this course.

Consider the scenario where our client starts downloading a file from a server inside a MANET locality (Fig.1a). Suddenly and transparently the server leaves the locality during the service session (Fig.1b). When a server leaves a locality, the provided services would become immediately unavailable for all currently served clients. In this situation, the client in the locality has to reorganize to reach the server independently of its movement, and to continue service session seamlessly. Depending on service implementation, the clients could either look for another equivalent server (if the provided service is stateless or the session state is maintained at the client side and exchanged at the server re-connection), or search for exactly the same server instance that left the locality (if the service is stateful and the state is exclusively stored at the server side).When a server leaves a locality, the provided services would become immediately unavailable for all currently served clients. When the servers possibly move, the model tries to exploits client/server location visibility to reorganize the locality via the dynamic election of a proxy agent (Fig.1c). The proxy takes care of searching servers by need, of forwarding client requests, and of performing multi hop routing it permits to organize solutions for client/server rebinding and service reestablishment that are scalable and mobility-transparent.

3. The model We use a detailed simulation model based on ns2 [12] and the file transfer protocol to measure the performance of our model. The protocol provides file downloading from a dynamically discovered service component available in a MANET locality, even if the server moves during file transfer.

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Once the proxy finds the server, (Fig.1e) the proxy starts forwarding service requests/responses from/to interested clients. In other words, all service messages are automatically and transparently sent through the proxy, acting as a bridge between the clients and the server. Another scenario is our client starts downloading a file from a server inside a MANET locality (Fig.2a). At the same time, during the downloading, our client informs his neighbours for the session (Fig.2b). The neighbours start watching the server and the project. When the server move, the other clients tries watching his movements (Fig.2c), the model tries to exploits the new location (Fig.2d). In this case the process of localisation by the neighbours last least.

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Figure3a. Downloading either directly from server using the AODV routing protocol, when (5 sec – 20 sec – 30 sec) is needed by clients to find the server leaving Figure 3b depicts the performance results when the using protocol is TORA. The configuration is exactly the same. According to this figure the results are similar and the gain for the download time is reduces.

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Fig.2. Client can download the file directly from a local server (a) in response to server movements our client informs his neighbours for the session (b); the neighbours start watching the server client (c, d).

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Figure3b. Downloading either directly from server using the TORA routing protocol, when (5 sec – 20 sec – 30 sec) is needed by clients to find the server leaving

4. Experimental Analysis We use the file transfer protocol to measure the performance of our model. The protocol provides file downloading from a dynamically discovered service component available in a MANET locality, even if the server moves during file transfer. At first, we measured how long it takes for a client to complete the transfer of various file capacity (i.e. 30, 60, 90, 120 and 150 MB file, approximately) first directly from a server that does not move during service provisioning and secondary when server leaves the MANET locality during the downloading and reconnects when entered in a new locality using the AODV routing protocol. In the first configuration (Figure3a) the time a client requires to find the information about the server leaving was assumed to be 5 second (5 sec), at the second (20 sec) and the third (30 sec).

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Figure 3c references to protocol RDMAR. According to this figure the results looks like the TORA protocol. 240

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Figure3c. Downloading either directly from server using the RDMAR routing protocol, when (5 sec – 20 sec – 30 sec) is needed by clients to find the server leaving

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Figure 3d references to protocol DSR. According to this figure this protocol has the most reduced gain for the download time.

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Figure3d. Downloading either directly from server using the DSR routing protocol, when (5 sec – 20 sec – 30 sec) is needed by clients to find the server leaving

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Figure3g. Downloading either directly from server using the CBRP routing protocol, when (5 sec – 20 sec – 30 sec) is needed by clients to find the server leaving

All above comparative curves at figures (3a, 3b, 3c, 3d, 3e, 3f and 3g) show that the performance of ABR and CBRP protocol is better than the others protocols at all configuration setups. Nevertheless, the gain for downloading time is greater for the AODV protocol under the use of second scenario (when the client informs his neighbours for the session and them start watching the server and the project).

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Figure3e. Downloading either directly from server using the SSR routing protocol, when (5 sec – 20 sec – 30 sec) is needed by clients to find the server leaving

5. Conclusions In this work, we have compared performance characteristics of on demand driven routing protocols (reactive) for ad-hoc network routing. The SSR protocol selects ways based on the force of channels between the nodes and on the stability of place of one node. For' this reason this protocol is enough time-consuming, after if exists some problem at the transmission the source is also

The best behavior for downloading time has the ABR and CBRP protocols. Figure3f refers to ABR and Figure3g to protocol CBRP. These both protocols have the same behaviour and similar results for our configuration.

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Figure 3e references to protocol SSR. According to this figure the results looks like the AODV protocol.

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Figure3f. Downloading either directly from server using the ABR routing protocol, when (5 sec – 20 sec – 30 sec) is needed by clients to find the server leaving

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chapter 5, pp.153-181, Kluwer Academic Publishers, 1996 [6] Per Johansson, Tony Larsson, Nicklas Hedman, and Bartosz Mielczarek Routing protocols for mobile ad-hoc networks- a comparative performance analysis. In Proceedings of the 5th International Conference on Mobile Computing and Networking (ACM MOBICOM’99), pages 195. 206, August 1999. [7] D. Johnson and D. Maltz.Dynamic Source routing in ad hoc wireless networks. In T. Imielinski and H.Korth, editors Mobile computing, chapter 5 Kluwer Academic, 1996. [8] J.Macker and S. Corson. Mobile ad hoc networks (MANET).http: www.ietf.org/ html.charters/manetcharter.html, 1997.IETF Working Group Charter. [9] David Maltz, Josh Broch, Jorjeta Jetcheva, and David Johnson the effects of on-demand behavior in routing protocols for multi-hop wireless ad hoc networks IEEE Journal on Selected Areas in Communication, 1999. [10] Charles Perkins and Elizabeth Royer Ad hoc on-demand distance vector routing. In Proceedings of the 2nd IEEE Workshop on Mobile Computing Systems and Applications, pages 90.100, Feb 1999. [11] Charles Perkins, Elizabeth Royer and Samir Das Ad hoc on demand distance vector (AODV) routing.http:// www.ietf.org/ internet-drafts/ draftietf-manet-aodv-03.txt, June 1999 IETF Internet. [12] Kevin Fall and Kannan Varadhan (Eds.) ns notes and documentation, 1999. Available from http://www-mash.cs.berkeley.edu/ns/

informed afterwards the nodes and the all process begins again from the start. Protocol SSR can present some delay, however and protocol AODV have the same disadvantage. However and protocol TORA can provide free courses of routes each moment, but provides also multiple ways. The TORA however, uses a different method of routing from the AODV, after it maintains information of routing only on the nodes that it thus has direct communication, it does not always use the most optimal way. Contrary to the AODV that we mentioned before that he is particularly evolutionary, DSR uses routing of source which does not leave the protocol to develop. The DSR has a serious disadvantage, that is to say, as long as it grows the network so much bigger they become the parcels of messages which occupy big breadth of area, something that as we said it does not happen in the AODV and TORA. The RDMAR calculates the distance between the nodes and as the AODV and TORA, uses algorithms in order to it maintains freedom of routes. Resemblance however they present also protocols ABR and CBRP. CBRP separates his nodes in teams (clusters) where the head cluster changes as much as possible more seldom and each node contains table of Neighbours. Protocol CBRP contrary to the TORA always finds the better way. References: [1] J. Macker, S. Corson, “Mobile Ad-hoc Networks (MANET)”,http://www.ietf.org/html.charters/manet -harter.html, 1997. [2] IEEE 802.11b Working Group, “Wireless LAN medium access control (MAC) and physical layer (PHY) specifications: higher speed physical layer (PHY) extension in the 2.4 GHz band”, http://grouper.ieee.org/groups/802/11/, 1999. [3] C. E. Perkins and P. Bhagwat, "Highly Dynamic Destination-Sequenced Distance-Vector Routing (DSDV) for Mobile Computers," ACM SIGCOMM'94 Conference on Communications Architectures, Protocols and Applications, pp. 234244, Aug. 1994. [4] D. B. Johnson and D. A. Maltz. Dynamic Source Routing in Ad Hoc Wireless Networks in Mobile Computing, Kluwer Publishing Company, 1996. [5] C. E. Perkins and E. M. Belding-Royer, "Ad-hoc On Demand Distance Vector Routing," 2nd IEEE Workshop on Mobile Computing Systems and Applications, pp. 90-100, Feb. 1999. [6] D.B. Johnson and D.A. Maltz, "Dynamic Source Routing in Ad Hoc Wireless Networks,'' in Mobile Computing, edited by T. Imielinski and H. Korth,

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