) "Network Simulator (NS-2)", www-mash.cs.berkeley.edu/ns/  Home/Search   Document Not in Database   Summary   Related Articles   Check

....of data per unit energy by adapting to the limited energy of the network. We found that in all of our simulations, nodes with a higher degree tended to dissipate more energy than nodes with a lower degree, creating potential weak points in a battery operated network. 4. 1 ns Implementation ns [15] is an event driven network simulator with extensive support for simulation of TCP, routing, and multicast protocols. To implement the SPIN family of data distribution protocols, we added several features to the ns simulator. The ns Node class was extended to create a ResourceAdaptive Node, as ....

ns-2 Network Simulator. http://www-mash.cs.berkeley.edu/ns/, 1998.

....AIMD and a binomial algorithm satisfying k l rule can achieve the same throughput. Further, it shows that for a given loss rate, two binomial connections will achieve same throughput provided other conditions are same. 3 Simulation results In this section, we present the results of our ns 2 [24] simulations of binomial control algorithms. We start by investigating the interactions between connections running a TCPfriendly binomial control algorithm (i.e. one that satisfies the k l rule) and TCP, as a function of k, which determines how aggressive the window increase factor is. We then ....

ns-2 Network Simulator. http://www-mash.cs.berkeley.edu/- ns/, 1998.

....and Section 6 summarizes our contributions. 2 Experimental Methodology The objective of our study is to evaluate the effect of higher priority EF traffic on the throughput and fairness of best effort TCP flows. We have conducted an extensive simulation study using the NS 2 network simulator [1]. In what follows, we describe our simulation environment, the design of our experiments, and the measures for the performance evaluation. 2.1 Simulation Environment 2.1.1 Network Topology We consider a network topology depicted in Figure 1; similar network topologies have been used in several ....

NS (Network Simulator). 1999. http://www-mash.cs.berkeley.edu/ns.

....make applications more network aware. Using this, applications can adapt to the state of the network. Applications are free from the burden of discovering traffic congestion and can find domain specific ways to adapt to changing network state. We have implemented the CM framework in the VINT ns 2 [16] simulator. We have also implemented TCP and a layered audio application over this framework. Details and performance evaluation of the architecture can be found in [2] We plan on moving the framework to a UNIX based kernel. This UNIX based implementation should provide an excellent testbed to ....

ns-2 Network Simulator. http://www-mash.cs.berkeley.edu/- ns/, 1998.

.... better at determining long term buffer requirements (i.e. large time granularities) it does not provide insight into how well statistical multiplexing performs, i.e. at small time granularities such as a round trip time (RTT) 3 Experimental Study To understand the dynamics of TCP, we use ns [9] to model the portion of the Energy Sciences network (ESnet) that is specific to our computational grid namely the network between Los Alamos National Laboratory (LANL) and Sandia National Laboratory (SNL) We then synthetically generate application generated traffic to better understand how ....

ns. Network Simulator. http://www-mash.cs.berkeley.edu/ns.

....show that the MP test improved the accuracy of the MP technique signi cantly. Thus in the remainder of this paper, and unless otherwise noted, we will use the MP test as the default test for the Markovian Probing (MP) technique. 4.2. Experimental Setup We used the Network Simulator (ns) [19] to simulate the topology illustrated in Figure 3. This topology represents a server and two clients. The shared portion of the paths between the server and the two clients is modeled by a single link (L1) whereas the disjoint portions of the paths between the server and the two clients are ....

ns: Network Simulator. http://www-mash.cs.berkeley.edu/ns/ns.html.

....their variation on our scheme. This is not achievable with the Internet. 41 Section 4.1.1 describes our choice of simulator and our enhancements to it. We then elaborate on our experiments in Section 4.1.2. 4.1. 1 Simulation Environment We use the UCB LBNL VINT network simulator ns (Version 2) [21] for our experiments. ns is a discrete event driven simulator initiated as a version of REAL [16] ns is primarily written in C [37] with MIT s Object Tcl (OTcl) 38] used as a command and con guration language. It has an object oriented architecture which allows modular addition of new ....

ns-2 Network Simulator. http://www-mash.cs.berkeley.edu/ns/, 1998.

....of IP address pair and port numbers. Additionally, there is no explicit need to use packets for the signalling of request messages. This could be done in band using header fields or a new kind of IPv6 extension header. 4 Simulations We have implemented the MUV algorithm into the ns simulator [26]. Simulations in [24] investigate MUV s behavior in scenarios with multiple congested gateways, varying number of flows, varying link capacities and delays, various traffic patterns aggregating CBR, ON OFF flows, aggressive TCP flows, TCP Reno and SACK TCP flows with and without ECN. Queue size ....

NS Simulator Homepage, http://www-mash.cs.berkeley.edu/ns/

....of data per unit energy by adapting to the limited energy of the network. We found that in all of our simulations, nodes with a higher degree tended to dissipate more energy than nodes with a lower degree, creating potential weak points in a battery operated network. 5. 1 ns Implementation ns [16] is an event driven network simulator with extensive support for simulation of TCP, routing, and multicast protocols. To implement the SPIN PP and SPIN EC protocols, we added several features to the ns simulator. The ns Node class was extended to create a Resource Adaptive Node, as shown in Figure ....

ns-2 Network Simulator. http://www-mash.cs.berkeley.edu/ns/, 1998.

....of data per unit energy by adapting to the limited energy of the network. We found that in all of our simulations, nodes with a higher degree tended to dissipate more energy than nodes with a lower degree, creating potential weak points in a battery operated network. 4. 1 ns Implementation ns [15] is an event driven network simulator with extensive support for simulation of TCP, routing, and multicast protocols. To implement the SPIN family of data distribution protocols, we added several features to the ns simulator. The ns Node class was extended to create a ResourceAdaptive Node, as ....

ns-2 Network Simulator. http://www-mash.cs.berkeley.edu/ns/, 1998.

....avoidance phase [min IN ; max IN ) and the congestion control phase [max IN ; 1) for IN packets. In the same form, minOUT , maxOUT and PmaxOUT de nes the corresponding phases for the OUT packets. 4 Simulation results The simulation of the Assured Service was done using the ns 2 simulator [8]. For this, it was necessary to implement the mechanisms that compose this service, i.e. trac conditioning mechanisms, such as policers and packet markers, and the mechanism of active queue management that implements the AF PHB itself. The mechanism used to check the trac conformity at the border ....

Network Simulator { NS (version 2), http://www-mash.cs.berkeley.edu/ns/

....a robust and lightweight protocol to elicit feedback from receivers about losses and status, and schedules data transmissions by apportioning available capacity between di erent active ows. The CM s internal algorithms and protocols are described in Section 4, where we justify them using ns based [20] simulations and analysis. The CM API is designed to enable easy application adaptation to congestion and variable bandwidth, accommodating heterogeneous ows. The API includes functions to query path status, schedule data transmissions, notify the CM upon data transmission, and update variables ....

ns-2 Network Simulator. http://www-mash.cs.berkeley.edu/ns/, 1998.

....trace. are within the range of latencies specified for high end interactive video [7] We use genuine MPEG 1 encoded Star Wars video trace [8] to drive our simulations. The trace can be obtained in both ASCII and in ns format [13] Fig. 1 represents a screen dump from network animator nam [11], a companion software tool to ns [12] used for visualization of the topology layout, packet level animation, and data inspection. In this example, a network with n = 10 sources, one router, and a sink is shown. The number of sources in the topology shown in Fig. 1 is only for illustration ....

Nam network animator, 1999, http://www-mash.cs.berkeley.edu/nam .

....with an arbitrary fairness model and ends with a contention resolution algorithm design that achieves the fairness model probabilistically. 3 Fairness Characteristics of the IEEE 802.11 MAC Protocol We now illustrate the fairness properties of IEEE 802.11 through three tests in the ns 2 simulator [11]. The simulation scenarios consist of both simple hand con gured topolo flow1 6 Contention among 7 flows Contention with 8 flows B A C D E H G F Contention among 3 flows flow11 flow9 10 Figure 1: Topology Asymmetric Contention flow1 4 A B C D E flow5 G F Figure 2: Topology: ....

\ns-2 Network Simulator," http://www-mash.cs.berkeley.edu/ns/, 1998.

....here. Our experimental evaluation indicated that a disjunctive test yielded better results, and is thus adopted in this paper. Harfoush, Bestavros, and Byers, Robust Identi cation of Shared Losses Using End to End Unicast Probes 12 4. 2 Experimental Setup We used the Network Simulator (ns) [18] to simulate the topology illustrated in Figure 3. This topology represents a server and two clients. The shared portion of the paths between the server and the two clients is modeled by a single link (L1) whereas the disjoint portions of the paths between the server and the two clients are ....

ns: Network Simulator. http://www-mash.cs.berkeley.edu/ns/ns.html.

....estimation. Comparison with the weighted TFRC work for achieving service differentiation is currently ongoing work, for which we expect to have results in the next month. D. Simulation Results In this section, we present the results of TCP LASD simulations, done using the ns 2 simulator [13]. We consider the same network setting as in Figure 3. The network routers perform 2e 06 4e 06 6e 06 8e 06 1e 07 1.2e 07 0 20 40 60 80 100 throughput (bps) weight weight weight ideal (weight = x) ideal (weight 1) Throughput (bps) Weight Weight=x Weight=1 x ideal (weight=x) ....

"ns-2 Network Simulator." http://www-mash.cs.berkeley.edu/ns/, 1998.

....given processors that are crashed for five minutes a day. Gossip sends roughly BF= t Gamma 1) 4 times as many messages as Harary graph flooding. To make a more detailed comparison of message overhead, we evaluated the performance of gossip and Harary graph flooding using the ns simulator [25]. We simulated Ethernet based networks. One of the networks we considered was a LAN of a single Ethernet, where there are 32 processors. 17 0 5 10 15 20 f 0.2 0.4 0.6 0.8 1.0 Canonical H(22,4) Modified H(22,4) Gossip B=3, F=2 Gossip B=2, F=2 Figure 7: Graceful degradation of gossip and ....

Network Simulator. http://www-mash.cs.berkeley.edu/ns. 21

....mobility management cost is important because different cellular system installations (e.g. pico cellular and macro cellular access networks) will operate under different mobility conditions. 3. 1 Simulation Environment The Cellular IP protocol is implemented as extensions to the ns simulator [10] which is widely used by the networking community to analyze IP networks. The Cellular IP simulation environment used for the reported results is shown in Figure 1; note that the simulator supports Cellular IP access networks of arbitrary topology. The assumptions and limitations of the Cellular ....

"Network Simulator", http://www-mash.cs.berkeley.edu/ns/ns.html.

....filtered out of a flow aggregate at the ILR and MUV could be performed only for these filtered flows. If flows are identified as unfriendly the total aggregate, or only the identified flows could be discriminated. 7 We have additionally implemented such a version of MUV in the network simulator [29] and have verified that counters stay synchronized in case per flow state of non terminated flows is deallocated. 9 . Within the context of this paper a flow is defined by IP Addresses and port numbers, respectively flow ID. As mentioned in [2] a flow could alternatively be defined only by ....

....in duplex mode. Request messages could be able to piggy back reply messages hence only two instead of four signalling messages per period would be required for such a flow. 4 Simulations We have implemented the MUV algorithm as explained in section 3.2 and section 3. 3 into the ns simulator [29]. Simulations in [28] investigate MUV s behavior in scenarios with multiple congested gateways, varying number of flows, varying link capacities and delays, various traffic patterns aggregating CBR, ON OFF flows, TCP nasty flows, TCP Reno and SACK TCP flows with and without ECN. Additionally, 28] ....

NS Simulator Homepage, http://www-mash.cs.berkeley.edu/ns/

....proportional to the total arrival rate at the router output port. For detailed explanations of RED pseudo code and discussion of further properties we have to refer to [23] due to space limitations in this paper. 4 SIMULATION OF RED We have implemented the RED algorithm in the ns simulator [10], version 2. Simulations in [23] include scenarios investigating different RED parameter settings, topologies, multiple congested gateways and different mixes of TCP, CBR and ON OFF flows. Additionally, scenarios showing RED with ECN packet marking instead of dropping [11] 21] for flows in state ....

NS Simulator Homepage, http://www-mash.cs.berkeley.edu/ns/

....C or C code, or a combination of the two. Simulator packages typically come with a set of pre coded modules, with the ability to customize these modules or add new ones. Some network simulators provide extensive support for visualization and animation (such as the nam package used with ns [ns 98] Examples of widely used network simulators include, in the public domain: ns [ns 98] VINT [VINT 98] REAL[Keshav 97] and MARS[ASDM 94] and commercially: OPNET[MIL3 98] and BONeS [Cadence 98] 5 Although network simulators are usually used to test protocol performance, they can also be ....

....a set of pre coded modules, with the ability to customize these modules or add new ones. Some network simulators provide extensive support for visualization and animation (such as the nam package used with ns [ns 98] Examples of widely used network simulators include, in the public domain: ns [ns 98] VINT [VINT 98] REAL[Keshav 97] and MARS[ASDM 94] and commercially: OPNET[MIL3 98] and BONeS [Cadence 98] 5 Although network simulators are usually used to test protocol performance, they can also be used as protocol development environments. Given a sufficiently accurate emulation of a ....

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ns network simulator, http://www-mash.cs.berkeley.edu/ns/

....of data per unit energy by adapting to the limited energy of the network. We found that in all of our simulations, nodes with a higher degree tended to dissipate more energy than nodes with a lower degree, creating potential weak points in a battery operated network. 4. 1 ns Implementation ns [14] is an event driven network simulator with extensive support for simulation of TCP, routing, and multicast protocols. To implement the SPIN family of data distribution protocols, we added several features to the ns simulator. The ns Node class was extended to create a Resource Adaptive Node, as ....

ns-2 Network Simulator. http://www-mash.cs.berkeley.edu/ns/, 1998.

....we combine networks with these different asymmetric characteristics and study the performance characteristics of TCP connections through them. We now describe the details of our simulation setup, workloads, and performance metrics. 3. 2 Simulation Setup and Performance Metrics We used ns [17], an event driven packet level network simulator from Berkeley and LBNL for our work. We developed several extensions to this simulator to model the networks of interest to us. We added the notion of a shared link (LAN) to the simulator with the ability to incorporate arbitrary link layer and ....

ns -- Network Simulator. http://www-mash.cs.berkeley. edu/ns/, 1996.

....impact the quality of the established video and or voice connections, and affect the throughput of bulk data transfers. These loss characteristics cannot be captured by specifying only the loss probability, but require a detailed study of loss patterns [3] In our study we use ns simulator [12] and genuine traffic traces to explore the loss behavior of video connections over User Datagram Protocol (UDP) We use wavelet anal This research was supported by the NSERC Grant 216844 99 and the BC Advanced Systems Institute Fellowship. ysis [4] to study the packet loss behavior on various ....

....latencies specified for high end interactive video [7] We use genuine MPEG 1 encoded Star Wars video trace [8] to drive our simulations. The trace can be obtained in both ASCII and in ns format [13] Fig. 1 represents a screen dump from network animator nam [11] a companion software tool to ns [12], used for visualization of the topology layout, packet level animation, and data inspection. In this example, a network with n = 10 sources, one router, and a sink is shown. The number of sources in the topology shown in Fig. 1 is only for illustration purposes. In our simulations, we experiment ....

ns-2 network simulator, 1999, http://www-mash.cs.berkeley.edu/ns .

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) "Network Simulator (NS-2)", www-mash.cs.berkeley.edu/ns/

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