Lans and mobility

[Ingela Anderton <ingela@docs.uu.se>]

Hi!

The thing I'm working on now is to try to create a small lan with
a base station and one mobile host and run this simulation with some
FTP traffic, and with and without the snoopmodel.

I started by constructing a lan with two nodes and setting up a FTP
session between them. This seems to work fine. But looking closer at
the trace file some lines like this one occured:

c 4.61552 1 0 ack 40 ------- 0 1.0 0.0 985 1973
c 4.61552 0 1 tcp 1000 ------- 0 0.0 1.0 1003 2005

What does c stand for? (I suppose maybe this could be a correct
behaviour, I just don't understand it. I can't find anything about a c
in the documentation.)

Well assuming I just missed something, I also tried to add a additional
node that should be the basestation, and a mobile host.
I've looked at forinstance snoop.tcl to try get clues on how to do this.

The problems I have is:

* If I try to run Snoop on the basstation I get erromessages like:
_o16: no target for slot 1073713900


(I don't think it should matter that I haven't crated any errormodel
to make the link to the mobile lossy yet, other than that the results
will not be very interesting. I'm trying to add a lite at the time to
reach my goal.)


This is my what my procedure for creating the topology looks like.

proc create-topology {} {
    global ns opt
    global lan node mobile
    
    # Number of nodes in the wiered lan (except the basstation)	
    set num_wired_nodes $opt(noNode) 
    
    # Create a list of nodes that belongs to the lan
    for { set i 0} {$i < $num_wired_nodes} {incr i} { ;# The nodes are enumerated from 0
	set node($i) [$ns node]
	    lappend node_list $node($i)
    }
    
    # Create the lan
    set lan [$ns newLan $node_list $opt(bw) $opt(delay) \
	    -llType $opt(ll) -ifqType $opt(ifq) \
	    -macType $opt(mac) -chanType $opt(chan)]
    
    # Create a new node that shall act as basestation
    set base [set num_wired_nodes]
    set node($base) [$ns node]    
    
    # Add the basestation for the mobile hosts to the lan
    $lan addNode [list $node($base)] $opt(bw) $opt(delay) LL/LLSnoop $opt(ifq) $opt(mac)
   
    # Crete the mobile node and link it to the basestation
    set mobile [expr $base + 1]
    puts $mobile
    set node($mobile) [$ns node]
    $ns duplex-link $node($mobile) $node($base) 10MB 1ms DropTail
   
}

-- 
/Ingela <Trying hard, but for the moment just bumping in to walls!> 

//The highway of life is always under construction. //

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