为了自己的MANET研究,最近一直做网络仿真。第一步就想做一个DSR路由协议的模拟。遗憾的是,例子中的代码实在是太简单了,根本没有实现多跳功能。网上找了不少版本,均有相应的问题,有的run起来数据通信太小,根本看不到多跳,有的压根就无法看到数据通信。
综合了一下网上的版本,修改了其中的错误,把NS2安装目录下的wireless-mitf.tcl做一下修正,分享一个可以看到多跳的基于DSR路由的模拟脚本。相信对于刚入门想做这个的人会有帮助。
脚本名字为multi-hop.tcl,生成的动画文件为multi_hop.nam。
#Copyright (c) 1997 Regents of the University of California.
# All rights reserved.
#
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# documentation and/or other materials provided with the distribution.
# 3. All advertising materials mentioning features or use of this software
# must display the following acknowledgement:
# This product includes software developed by the Computer Systems
# Engineering Group at Lawrence Berkeley Laboratory.
# 4. Neither the name of the University nor of the Laboratory may be used
# to endorse or promote products derived from this software without
# specific prior written permission.
#
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# $Header: /cvsroot/nsnam/ns-2/tcl/ex/wireless-mitf.tcl,v 1.2 2000/08/30 00:10:45 haoboy Exp $
#
# Simple demo script for the new APIs to support multi-interface for
# wireless node.
#
# Define options
# Please note:
# 1. you can still specify "channelType" in node-config right now:
# set val(chan) Channel/WirelessChannel
# $ns_ node-config ...
# -channelType $val(chan)
# ...
# But we recommend you to use node-config in the way shown in this script
# for your future simulations.
#
# 2. Because the ad-hoc routing agents do not support multiple interfaces
# currently, this script can't generate anything interesting if you config
# the interfaces of node 1 and 2 on different channels
#
# --Xuan Chen, USC/ISI, July 21, 2000
#
set val(chan) Channel/WirelessChannel ;#Channel Type
set val(prop) Propagation/TwoRayGround ;# radio-propagation model
set val(netif) Phy/WirelessPhy ;# network interface type
set val(mac) Mac/802_11 ;# MAC type
# 如果用DSR,则需要用CMUPriQueue队列,否则用Queue/DropTail/PriQueue
set val(ifq) CMUPriQueue ;#Queue/DropTail/PriQueue ;# interface queue type
set val(ll) LL ;# link layer type
set val(ant) Antenna/OmniAntenna ;# antenna model
set val(ifqlen) 50 ;# max packet in ifq
set val(nn) 3 ;# number of mobilenodes
#set val(rp) DSDV ;# routing protocol
set val(rp) DSR ;# routing protocol
set val(x) 500
set val(y) 500
# Initialize Global Variables
set ns_ [new Simulator]
set tracefd [open multi_hop.tr w]
$ns_ trace-all $tracefd
set namtrace [open multi_hop.nam w]
$ns_ namtrace-all-wireless $namtrace $val(x) $val(y)
# set up topography object
set topo [new Topography]
$topo load_flatgrid $val(x) $val(y)
# Create God
# 这几句和下面的god set set-dist相关
# 我觉得不要手动设置最短路径也行的。
#set god [create-god $val(nn)]
create-god $val(nn)
# New API to config node:
# 1. Create channel (or multiple-channels);
# 2. Specify channel in node-config (instead of channelType);
# 3. Create nodes for simulations.
# Create channel #1 and #2
set chan_1_ [new $val(chan)]
set chan_2_ [new $val(chan)]
set chan_3_ [new $val(chan)]
# Create node(0) "attached" to channel #1
# configure node, please note the change below.
$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) /
-topoInstance $topo /
-agentTrace ON /
-routerTrace ON /
-macTrace ON /
-movementTrace OFF /
-channel $chan_1_
set node_(0) [$ns_ node]
# node_(1) can also be created with the same configuration, or with a different
# channel specified.
# Uncomment below two lines will create node_(1) with a different channel.
# $ns_ node-config /
# -channel $chan_2_
set node_(1) [$ns_ node]
set node_(2) [$ns_ node]
$node_(0) random-motion 0
$node_(1) random-motion 0
$node_(2) random-motion 0
#
# Provide initial (X,Y, for now Z=0) co-ordinates for mobilenodes
# 设置节点的初始位置
# 注意设置节点位置的代码必须放到设置节点大小的代码前面
$node_(0) set X_ 0.0
$node_(0) set Y_ 0.0
$node_(0) set Z_ 0.0
$node_(1) set X_ 300.0
$node_(1) set Y_ 255.0
$node_(1) set Z_ 0.0
$node_(2) set X_ 100.0
$node_(2) set Y_ 100.0
$node_(2) set Z_ 0.0
# $god set set-dist 0 2 2
# $god set set-dist 0 1 1
# $god set set-dist 1 2 1
# 注意这点代码必须放到上述设置节点位置的后面
# 不然的话,初始的节点会混到一起,居然有这个bug
for {set i 0} {$i < $val(nn)} {incr i} {
# 设置节点的大小
$ns_ initial_node_pos $node_($i) 30
}
#
# Now produce some simple node movements
# Node_(1) starts to move towards node_(0)
#
$ns_ at 3.0 "$node_(0) setdest 48.0 38.0 5.0"
$ns_ at 3.0 "$node_(1) setdest 220.0 50.0 25.0"
$ns_ at 3.0 "$node_(2) setdest 450.0 400.0 8.0"
# Node_(1) then starts to move away from node_(0)
$ns_ at 20.0 "$node_(2) setdest 490.0 480.0 30.0"
# Setup traffic flow between nodes
# TCP connections between node_(0) and node_(2)
set tcp [new Agent/TCP]
$tcp set class_ 2
set sink [new Agent/TCPSink]
$ns_ attach-agent $node_(0) $tcp
$ns_ attach-agent $node_(2) $sink
$ns_ connect $tcp $sink
set ftp [new Application/FTP]
$ftp attach-agent $tcp
$ns_ at 3.0 "$ftp start"
#
# Tell nodes when the simulation ends
#
for {set i 0} {$i < $val(nn) } {incr i} {
$ns_ at 30.0 "$node_($i) reset";
}
$ns_ at 30.0 "stop"
$ns_ at 30.01 "puts /"NS EXITING.../" ; $ns_ halt"
proc stop {} {
global ns_ tracefd
$ns_ flush-trace
close $tracefd
}
puts "Starting Simulation..."
$ns_ run
说明,上述脚本中,生成了3个无线网络节点,都处于运动状态。最后第三个节点node2跑出了node0和node1的范围。本脚本模拟了网络由一跳到二跳到最终分裂的过程。
但愿对相应需求的和我一样的初学者能少走弯路