Error Model For Wireless In Ns2

[ date ] [ thread ] [ subject ] [ author ] Hi Aleksandar, In order to generate random errors first you have to create the error model in your script and wireless ns2 examples then attach it to the link or node where you want the packets xgraph example wireless ns2 to be dropped. For creating a random uniformly distributed errors you can type: #Create the error model set em [new ErrorModel]

Error Model In Ns2

$em unit pkt $em set rate_ 0.03 ;# PER = 3% $em ranvar [new RandomVariable/Uniform] $em drop-target [new Agent/Null] The way you attach error models to the links is different for wired and wireless scenarios.

Loss Model In Ns2

If you are working with wired scenarios you have different places where you can insert the error model, you can check page 127 of the ns2 manual, I use: #attach the model to the link $ns link-lossmodel $em $n0 $n1 If you are working with wireless scenarios you can attach the error model by adding one option in node-config: $ns_ node-config -incomingErrProc $em or $ns_ node-config -outgoingErrProc $em You can find detailed information of the differences between using the first or the second option also in page 127 of the ns2 manual. I must say that I couldn't use the error models in wireless scenarios. There is some problem with the -incomingErrProc and -outgoingErrProc options, they don't insert the error model in the simulation. In other words, the error model is created but it is never used so no packets are dropped. I have this problem when I use 802.11 it may appear in all kind of wireless scenarios. I asked to this list but I got no answer. Currently I am working in error models of wireless, so if you are also working in wireless I can send you more information on the topic. Regards, Guillermo Hi all, I need to setup link between two nodes where I have RANDOM ERRORS with PER (packet error rate) = 10exp-7, 10exp-6,10exp-5.... etc. So, I need to setup Error generator in ns2. Can somebody tell me how to do this? Thanks. A. Previous message: [ns] IPv6 support in NS-2 Next message: [ns] NS2 Installation problem with cygwin Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] More information about the Ns-users mailing list

attach the error model, add following codes to a TCL simulation script .......... proc UniformErr {} { set err [new ErrorModel] $err unit packet $err set rate_ 0.05 return $err http://zbinwu.blogspot.com/2010/10/simulating-wireless-link-errors.html } # $err rate_ 0.5 "invalid command ErrModel::Command does not support" # the https://groups.google.com/d/topic/ns-users/VetJf8ljslI other valid method is " set err [new ErrorModel/Uniform 0.05 pkt] " # the parameter rate ( 0 or 0.9) is a threshold that all packets all going through and 90% packets are # going to be drop proc TwoStateMarkovErr {} { set tmp0 [new ErrorModel/Uniform 0 pkt] set tmp1 [new ErrorModel/Uniform in ns2 .7 pkt] # Array of states (error models) set m_states [list $tmp0 $tmp1] # Durations for each of the states, tmp, tmp1 and tmp2, respectively set m_periods [list 0.1 .075 ] # Transition state model matrix set m_transmx { {0.9 0.1 } {0.7 0.3 } } set m_trunit byte # Use time-based transition set m_sttype time set m_nstates 2 set m_nstart [lindex $m_states 0] set model in ns2 em [new ErrorModel/MultiState $m_states $m_periods $m_transmx \ $m_trunit $m_sttype $m_nstates $m_nstart] return $em } $ns_ node-config -adhocRouting $val(rp) \ -llType $val(ll) \ -macType $val(mac) \ -ifqType $val(ifq) \ -ifqLen $val(ifqlen) \ -antType $val(ant) \ -propType $val(prop) \ -phyType $val(netif) \ -channel $chan1 \ -topoInstance $topo \ -agentTrace ON \ -routerTrace OFF\ -macTrace ON \ -movementTrace OFF \ -IncomingErrProc TwoStateMarkovErr #\ #-OutcomingErrProc TwoStateMarkovErr #The other way to configure error # $ns_ node-config --IncomingErrProc $opt(err) Posted by Zhibin Wu at 1:34 PM 1 comment: Vinit Mahiwal said... It gives error. Error model doesn't work with wireless network. February 18, 2014 at 10:02 PM Post a Comment Newer Post Older Post Home Subscribe to: Post Comments (Atom) Blog Archive ▼ 2010 (20) ► November (4) ▼ October (16) MAC Interface in ns-2 Why List-based improvement in ns-2.27 cause proble... Ricean Fading based probabilistic Link Error "init" function of OTCL Demystify TwoRayGround propagation model Introduction to packet headers and addresses in ns... Analyze ns-2 trace file NS-2 Tutorials Traffic Pattern Generation Node Movement and Topology Generation Simulating wireless link errors Network Simulator 2 script for a complex scenario A simple example for wireless simulation scenario Debugging ns-2

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