K. Fall and K. V. (Eds.). ns notes and documentation, 1999. available from http://www-mash.cs.berkeley.edu/ns/.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....section. Their performances are compared with the base DSR protocol. In the following, we first describe the simulation environment and the performance metrics used, and then present and analyze the simulation results. 4. 1 Simulation Environment We use a detailed simulation model based on ns 2 [5]. In a recent work, the Monarch research group in CMU developed support for simulating multi hop wireless networks complete with physical, data link and MAC layer models [2] on ns 2. The distributed coordination function (DCF) of IEEE 802.11 [4] for wireless LANs is used as the MAC layer. The ....

....layer. The radio model uses characteristics similar to a commercial radio interface, Lucent s WaveLAN [14] WaveLAN is a shared media radio with a nominal bit rate of 2 Mb sec and a nominal radio range of 250 meters. A detailed description of simulation environment and the models is available in [2, 5] and will not be presented here. Note that the same simulation environment has been used before in several recent performance studies on ad hoc networks [2, 6, 11, 9, 3] In the following, we mention some of the features of the simulation environment to provide a context for the performance ....

K. Fall and K. V. (Eds.). ns notes and documentation, 1999. available from http://www-mash.cs.berkeley.edu/ns/.

....5.2. Balancing Battery Life In order to measure the ability of the path state mechanisms to manage the battery resources of an ad hoc network, we must first extend our simulator to track the energy level available at each node. Work on this is already under way as part of VINT development effort [11]. This framework enables us to experiment with algorithms for retrieving routes from the route cache. The algorithms will use the path metrics stored in the route cached by the path state mechanisms to select routes that balance the energy levels of the nodes over time. We will evaluate the ....

Kevin Fall and Kannan Varadhan, editors. ns Notes and Documentation. The VINT Project, UC Berkeley, LBL, USC/ISI, and Xerox PARC, January 1999. Available from http://www-mash.cs.berkeley.edu/ns/.

.... of wireless ad hoc networks of 50 mobile nodes, with realistic modeling of factors such as medium access control and contention, collisions, wireless signal strength and propagation delay, carrier sense, and capture effect [2] based on our extended version of the ns 2 network simulator [3]. We simulated each of the caching algorithms primarily over a set of 50 different movement scenarios drawn from 5 different types of mobility models. To better characterize the relative difficulty that each movement scenario presents to the routing protocol, we utilize a set of mobility metrics, ....

....transmission range for each link of 250 m. 5. Methodology 5.1. Simulator We analyzed the effects the different caching strategy design choices through detailed simulation of the different caching algorithms described in Section 4. The experiments were conducting using the ns 2 network simulator [3], which we have extended to support the simulation of wireless and mobile networks [2] The simulator properly models signal strength, RF propagation, propagation delay, wireless medium contention, capture effect, interference, and arbitrary continuous node mobility. The radio model is based on ....

Kevin Fall and Kannan Varadhan, editors. ns Notes and Documentation. The VINT Project, UC Berkeley, LBL, USC/ISI, and Xerox PARC, November 1997. Available from http://www-mash.cs.berkeley.edu/ns/.

....36 TCP (a) b) Figure 1: Comparison of a TCP ELFN and a TCP ow in a dynamic scenario for two di erent pair of end hosts. The scenario is 50 nodes in a 1500m 300m area with maximum speed of 20m s and zero pause time. 2 Simulation Environment For all our simulation studies, we have used the ns2 [7] simulator and its ad hoc extensions provided by the Monarch [8] research group at CMU. Like previous work on ELFN[1, 2, 5] we have also used the DSR [6] protocol for routing in our simulations. Our tests are on mobile and static scenarios. The packet size used is 1460 bytes of data. The channel ....

K. Fall and K. Vardhan, \ns notes and documentation," available from http://wwwmash. cs.berkeley.edu/ns/, 1999.

....hence very few updates may need to be generated to the locator sensor. A disadvantage to the use of forwarding pointers is the difficulty to maintain pointers under high network dynamics. 3.2. Simulation set up We compare the overhead incurred by the SCOUT AGG and SCOUT MAP schemes using the ns[12] network simulator. We mainly compare the bandwidth overhead incurred by the schemes but we also consider query loss rates for scenarios that involve sensor failures. Unless otherwise stated, our scenarios consist of connected topologies of 300 wireless sensors with a transmission range of 120 ....

Kevin Fall and Kannan Varadhan, editors. ns Notes and Documentation. The VINT Project. Available from http://wwwmash. cs.berkeley.edu/ns/, Oct. 1998.

....need to be generated to the locator sensor. A disadvantage to the use of forwarding pointers is the higher state overhead in the network as well as the relatively higher diculty to maintain pointers under high network dynamics. 3. 2 Simulation We next describe some simulation results with the ns[18] network simulator. We mainly compare the bandwidth overhead of the SCOUT AGG and SCOUT MAP schemes. We also consider query loss rates for scenarios that involve sensor failures. Unless otherwise stated, our scenarios consist of connected topologies of 300 wireless sensors with a transmission ....

Kevin Fall and Kannan Varadhan, editors. ns Notes and Documentation. The VINT Project. Available from http://www-mash.cs.berkeley.edu/ns/, October 1998.

....process as DSR except that forwarding state is now set up at intermediate nodes from the source to the destination during the above route discovery process. Hence the packets need not carry the source route in order to reach the destination. Broch et al. 90] have made extensions to the ns 2[91] simulator to simulate networks of mobile nodes with a realistic radio propagation model. They have compared the DSDV, TORA, DSR and AODV protocols 13 through simulation. Their results indicate that DSR performs better than the other protocols in terms of packet delivery ratio, routing overhead ....

....are each detecting a number of tagged objects. The tagged objects as well as the sensors may be mobile. An event driven simulator will be required to capture the effects of network dynamics due to mobility as well as failure and recovery of nodes. We expect to base our framework on the the ns 2[91] simulator that is event driven and also supports mobility of nodes. Develop test suites that cover an interesting range of event and network dynamics: The scenarios that we investigate will consist of thousands of sensors dispersed over a wide region. Sinks appear randomly in the network and ....

Kevin Fall and Kannan Varadhan, editors. ns Notes and Documentation. The VINT Project. Available from http://www-mash.cs.berkeley.edu/ns/, October 1998. 56

....The goal of our simulations that follow is to determine the relative merits of the aggressive use of source routing and caching in DSR, and the more conservative routing table and sequence number driven approach in AODV. IV. SIMULATION MODEL We use a detailed simulation model based on ns 2 [7] in our evaluation. In a recent work, the Monarch research group in CMU developed support for simulating multi hop wireless networks complete with physical, data link and MAC layer models [2] on ns 2. The distributed coordination function (DCF) of the new IEEE standard 802.11 [5] for wireless LANs ....

....radio model uses characteristics similar to a commercial radio interface, Lucent s WaveLAN [6] 17] WaveLAN is a shared media radio with a nominal bit rate of 2 Mb sec and a nominal radio range of 250 meters. A detailed description of simulation environment and the models is available in [2] [7]. The routing protocol model sees all data packets transmitted or forwarded, and responds by invoking routing activities as appropriate. The RREQ packets are treated as broadcast packets in the MAC. RREP, RERR and data packets are all unicast packets with a specified neighbor as the MAC ....

Kevin Fall and Kannan Varadhan (Eds.). ns notes and documentation, 1999. available from http://www-mash.cs.berkeley.edu/ns/.

....level i sensors are identical) Further discussion of the rules to prevent oscillations are however beyond the scope of this paper. 3 Comparison of SCOUT AGG and SCOUT MAP schemes We compare the bandwidth overhead incurred by the SCOUT AGG and SCOUT MAP schemes for various scenarios using the ns[16] network simulator. We also consider query loss rates for scenarios that involve sensor failures. Unless otherwise stated, our scenarios consist of connected topologies of 300 wireless sensors with a transmission range of 120 meters and 3000 objects randomly distributed in a rectangular region of ....

Kevin Fall and Kannan Varadhan, editors. ns Notes and Documentation. The VINT Project. Available from http://www-mash.cs.berkeley.edu/ns/, October 1998.

.... Routing protocol (DSR) 1, 4, 5] and to compare its performance to other proposed ad hoc network routing protocols [2] Our simulation environment consists of a set of wireless and mobile extensions that we have created [2] based on the publicly available ns 2 simulator from the VINT Project [3]. 1 The Monarch Project is named in reference to the migratory behavior of the monarch butterfly, and can also be considered as an acronym for Mobile Networking Architectures. These extensions provide a detailed model of the physical and link layer behavior of a wireless network and allow ....

Kevin Fall and Kannan Varadhan, editors. ns Notes and Documentation. The VINT Project, UC Berkeley, LBL, USC/ISI, and Xerox PARC, January 1999. Available from http://www-mash.cs.berkeley.edu/ns/.

....does this by listening promiscuously to the next node s transmissions. If the next node does not forward the packet, then it is misbehaving. The pathrater uses this knowledge of misbehaving nodes to choose the network path that is most likely to deliver packets. Using the ns network simulator [8], we show that the two techniques increase throughput by 17 in the presence of up to 40 misbehaving nodes during moderate mobility, while increasing the ratio of overhead transmissions to data transmissions from the standard routing protocol s 9 to 17 . During extreme mobility, watchdog and ....

.... nd a path free of misbehaving nodes, it sends out a route request if we have enabled an extension we call Send Route Request (SRR) 4. METHODOLOGY In this section we describe our simulator, simulation parameters, and measured metrics. We use a version of Berkeley s Network Simulator (ns) [8] that includes wireless extensions made by the CMU Monarch project. We also use a visualization tool from CMU called ad hockey [25] to view the results of our simulations and detect overall trends in the network. To execute the simulations, we use PCs (450 or 500 MHz Pentium IIIs with at least 128 ....

K. Fall and K. Varadhan, editors. ns notes and documentation. The VINT Project, UC Berkeley, LBL, USC/ISI, and Xerox PARC, July 1999. Available from http://www-mash.cs.berkeley.edu/ns/.

....The goal of our simulations that follow is to determine the relative merits of the aggressive use of source routing and caching in DSR, and the more conservative routing table and sequence number driven approach in AODV. IV. SIMULATION MODEL We use a detailed simulation model based on ns 2 [7] in our evaluation. In a recent work, the Monarch research group in CMU developed support for simulating multi hop wireless networks complete with physical, data link and MAC layer models [2] on ns 2. The distributed coordination function (DCF) of IEEE 802.11 [5] for wireless LANs is used as the ....

....The radio model uses characteristics similar to a commercial radio interface, Lucent s WaveLAN [6] 16] WaveLAN is a sharedmedia radio with a nominal bit rate of 2 Mb sec and a nominal radio range of 250 meters. A detailed description of simulation environment and the models is available in [2] [7]. The routing protocol model sees all data packets transmitted or forwarded, and responds by invoking routing activities as appropriate. The RREQ packets are treated as broadcast packets in the MAC. RREP, RERR and data packets are all unicast packets with a specified neighbor as the MAC ....

Kevin Fall and Kannan Varadhan (Eds.). ns notes and documentation, 1999. available from http://www-mash.cs.berkeley.edu/ns/.

....to study a large number of points in the DSR design space and to directly compare the results of the simulations, since we were able to hold constant factors such as the communication and movement pattern between runs of the simulator. We conducted the experiments using the ns 2 network simulator [4] extended with our support for realistic modeling of mobility and wireless communication [2] The simulator allows the specification of arbitrary movement patterns for the nodes, and correctly models the effects of contention for the media and the distance between nodes in determining whether a ....

Kevin Fall and Kannan Varadhan, editors. ns Notes and Documentation. The VINT Project, UC Berkeley, LBL, USC/ISI, and Xerox PARC, January 1999. Available from http://www-mash.cs.berkeley.edu/ns/.

....wireless ad hoc network routing protocols. We present results of detailed simulations showing the relative performance of four recently proposed ad hoc routing protocols: DSDV [18] TORA [14, 15] DSR [9, 10, 2] and AODV [17] To enable these simulations, we extended the ns 2 network simulator [6] to include: ffl Node mobility. ffl A realistic physical layer including a radio propagation model supporting propagation delay, capture effects, and carrier sense [20] ffl Radio network interfaces with properties such as transmission power, antenna gain, and receiver sensitivity. ffl The ....

....moving about and communicating with each other. We analyze the performance of each protocol and explain the design choices that account for their performance. 2 Simulation Environment ns is a discrete event simulator developed by the University of California at Berkeley and the VINT project [6]. While it provides substantial support for simulating TCP and other protocols over conventional networks, it provides no support for accurately simulating the physical aspects of multi hop wireless networks or the MAC protocols needed in such environments. Berkeley has recently released ns code ....

Kevin Fall and Kannan Varadhan, editors. ns notes and documentation. The VINT Project, UC Berkeley, LBL, USC/ISI, and Xerox PARC, November 1997. Available from http://www-mash.cs.berkeley.edu/ns/.

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