The ns Manual (formerly ns Notes and Documentation)1 - NM Lab at ...
The ns Manual (formerly ns Notes and Documentation)1 - NM Lab at ... The ns Manual (formerly ns Notes and Documentation)1 - NM Lab at ...
$client log These consist configuration of the Http client. It is attached to a central page pool . Next a random variable is attached to the client that is used by it (client) to generate intervals between two consecutive requests. Lastly the client isattached to a log file for logging its events.$cache log This is part of cache configuration that allows the cache to log its events in a log-file.$client connect $cache connect Once the client, cache, and server are configured, they need to be connected as shown in above commands.$client start-session This starts sending request for a random page from the client to the via .359
Chapter 40Worm ModelIn this chapter, we describe a scalable worm propagation model in ns, namely the detailed-network and abstract-network (DN-AN) model. It combines packet-level simulations with analytic worm spreading model. As shown in Figure 40.1, we modelthe Internet with two parts: detailed, and abstract part. A detailed-network could be an enterprise-network or the networkrun by an ISP. It simulates network connectivity and packet transmission. Users can evaluate worm detection algorithms inthe detailed network. On the other hand, we abstract the rest of the Internet with a mathematical model, namely susceptibleinfectious-removal(SIR) model (refer to [13] for detailed descriptions). Compared to the detailed network, we only trackseveral state variables in the abstract world, such as the number of infected hosts. The interaction between DN and AN isthrough actual packet transmissions, that is, the probing traffic generated by compromised hosts in both parts.For detailed description on DN-AN model, please refer to our draft paper. We implement the worm propagation model asapplications. The source code can be found at ~ns//apps/worm.{cc,h}. There is also a sample script to illustrate the DN-ANmodel under ~ns//tcl/ex/worm.tcl.40.1 OverviewWe implement the worm propagation model with three classes: class WormApp, DnhWormApp, and AnWormApp.class WormAppnd class DnhWormAppre used in the detailed network, representing invulnerable and vulnerable hostsrespectively. class AnWormApps the abstract network. Currently, our model only supports UDP-based worms.An vulnerable host is compromised upon receiving a probing packet. Then, it chooses a target host (randomly or with certainpreference to local neighbors) to scan. Probing packets have no effect on invulnerable hosts. When the abstract networkreceives probing packets, it updates its current states.probingtrafficthe restunprotectedInternetthe protected networkFigure 40.1: The DN-AN model.360
- Page 309 and 310: Chapter 36Agent/SRMThis chapter des
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Chapter 40Worm ModelIn this chapter, we describe a scalable worm propag<strong>at</strong>ion model in <strong>ns</strong>, namely the detailed-network <strong>and</strong> abstract-network (DN-AN) model. It combines packet-level simul<strong>at</strong>io<strong>ns</strong> with analytic worm spreading model. As shown in Figure 40.1, we modelthe Internet with two parts: detailed, <strong>and</strong> abstract part. A detailed-network could be an enterprise-network or the networkrun by an ISP. It simul<strong>at</strong>es network connectivity <strong>and</strong> packet tra<strong>ns</strong>mission. Users can evalu<strong>at</strong>e worm detection algorithms inthe detailed network. On the other h<strong>and</strong>, we abstract the rest of the Internet with a m<strong>at</strong>hem<strong>at</strong>ical model, namely susceptibleinfectious-removal(SIR) model (refer to [13] for detailed descriptio<strong>ns</strong>). Compared to the detailed network, we only trackseveral st<strong>at</strong>e variables in the abstract world, such as the number of infected hosts. <strong>The</strong> interaction between DN <strong>and</strong> AN isthrough actual packet tra<strong>ns</strong>missio<strong>ns</strong>, th<strong>at</strong> is, the probing traffic gener<strong>at</strong>ed by compromised hosts in both parts.For detailed description on DN-AN model, please refer to our draft paper. We implement the worm propag<strong>at</strong>ion model asapplic<strong>at</strong>io<strong>ns</strong>. <strong>The</strong> source code can be found <strong>at</strong> ~<strong>ns</strong>//apps/worm.{cc,h}. <strong>The</strong>re is also a sample script to illustr<strong>at</strong>e the DN-ANmodel under ~<strong>ns</strong>//tcl/ex/worm.tcl.40.1 OverviewWe implement the worm propag<strong>at</strong>ion model with three classes: class WormApp, DnhWormApp, <strong>and</strong> AnWormApp.class WormAppnd class DnhWormAppre used in the detailed network, representing invulnerable <strong>and</strong> vulnerable hostsrespectively. class AnWormApps the abstract network. Currently, our model only supports UDP-based worms.An vulnerable host is compromised upon receiving a probing packet. <strong>The</strong>n, it chooses a target host (r<strong>and</strong>omly or with certainpreference to local neighbors) to scan. Probing packets have no effect on invulnerable hosts. When the abstract networkreceives probing packets, it upd<strong>at</strong>es its current st<strong>at</strong>es.probingtrafficthe restunprotectedInternetthe protected networkFigure 40.1: <strong>The</strong> DN-AN model.360