📄 sat-aloha.tcl
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## Copyright (c) 1999 Regents of the University of California.# All rights reserved.## Redistribution and use in source and binary forms, with or without# modification, are permitted provided that the following conditions# are met:# 1. Redistributions of source code must retain the above copyright# notice, this list of conditions and the following disclaimer.# 2. Redistributions in binary form must reproduce the above copyright# notice, this list of conditions and the following disclaimer in the# 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 MASH Research# Group at the University of California Berkeley.# 4. Neither the name of the University nor of the Research Group may be# used to endorse or promote products derived from this software without# specific prior written permission.## THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE# ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF# SUCH DAMAGE.## Contributed by Tom Henderson, UCB Daedalus Research Group, June 1999## $Header: /nfs/jade/vint/CVSROOT/ns-2/tcl/ex/sat-aloha.tcl,v 1.5 2001/11/06 06:20:11 tomh Exp $# # Simple script with a geostationary bent-pipe (repeater) satellite and # one hundred terminals using unslotted (pure) Aloha random access. The# traffic sources consist of exponential on-off traffic generators unless# indicated below. With the traffic rates configured below, approximately # one tenth of the packets collide and must be retransmitted.# # Tests:# 1. basic: Mac operates in stop-and-wait mode (one outstanding packet# at a time). Collisions and drops are not traced. This test# should provide similar results to the satellite test suite.# 2. basic_tracing: Same as "basic", but drops ("d") and collisions ("c")# are instead explicitly traced. Again, similar to test suite # 3. poisson: Packets arrive according to Poisson process. Each source # still operates in stop-and-wait mode, and collisions and # drops are traced. rtx_limit_ == 0 (no persistence).# This can be used to try to approximate theoretical # unslotted Aloha results, if the number of terminals is large# compared to the arrival rate (so that no packets are queued)# 4. [FOR FUTURE WORK]. (larger than one packet rxmit buffer, different# traffic generator?)# if { $argc != 1 } { puts stderr {usage: ns sat-aloha.tcl [basic basic_tracing poisson]} exit 1}set test_ $argvputs "Running test $test_ ..."global nsset ns [new Simulator]# Global configuration parameters for Aloha (also settable in ns-sat.tcl)Mac/Sat/UnslottedAloha set mean_backoff_ 1s ; # mean exponential backoff time(s)Mac/Sat/UnslottedAloha set rtx_limit_ 3; # max number of retrans. attempted Mac/Sat/UnslottedAloha set send_timeout_ 270ms; # resend if send times outif { $test_ == "basic"} { Mac/Sat set trace_collisions_ false Mac/Sat set trace_drops_ false}global optset opt(chan) Channel/Satset opt(bw_up) 2Mbset opt(bw_down) 2Mbset opt(phy) Phy/Satset opt(mac) Mac/Sat/UnslottedAlohaset opt(ifq) Queue/DropTailset opt(qlim) 50set opt(ll) LL/Satset opt(wiredRouting) OFF# XXX This tracing enabling must precede link and node creation set outfile [open out.tr w]$ns trace-all $outfile# Set up satellite and terrestrial nodes# GEO satellite at 0 degrees longitude $ns node-config -satNodeType geo-repeater \ -llType $opt(ll) \ -ifqType $opt(ifq) \ -ifqLen $opt(qlim) \ -macType $opt(mac) \ -phyType $opt(phy) \ -channelType $opt(chan) \ -downlinkBW $opt(bw_down) \ -wiredRouting $opt(wiredRouting)set n1 [$ns node]$n1 set-position 0# Place 50 terminals at 100 different locations$ns node-config -satNodeType terminalset num_nodes 100for {set a 1} {$a <= $num_nodes} {incr a} { set n($a) [$ns node] $n($a) set-position [expr -15 + $a * 0.3] [expr 15 - $a * 0.3] $n($a) add-gsl geo $opt(ll) $opt(ifq) $opt(qlim) $opt(mac) $opt(bw_up) \ $opt(phy) [$n1 set downlink_] [$n1 set uplink_]}for {set a 1} {$a <= $num_nodes} {incr a} { set b [expr int($a + (0.5 * $num_nodes))] if {$b > $num_nodes} { incr b [expr -1 * $num_nodes] } set udp($a) [new Agent/UDP] $ns attach-agent $n($a) $udp($a) set exp($a) [new Application/Traffic/Exponential] $exp($a) attach-agent $udp($a) $exp($a) set rate_ 1Kb if {$test_ == "poisson"} { $exp($a) set rate_ 10000Mb $exp($a) set burst_time_ 0 $exp($a) set idle_time_ 5 } set null($a) [new Agent/Null] $ns attach-agent $n($b) $null($a) $ns connect $udp($a) $null($a) $ns at 1.0 "$exp($a) start"}$ns trace-all-satlinks $outfile# We use centralized routingset satrouteobject_ [new SatRouteObject]$satrouteobject_ compute_routes$ns at 100.0 "finish"proc finish {} { global ns outfile $ns flush-trace close $outfile exit 0}$ns run
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