cac.tcl~

This is a simulator written in Tcl to simulate a network node carrying GSM and GPRS traffics with Qo

# excute call admission control based on Equivalent Bandwidth of each traffic type
 
proc CAC { trafname EquivBW endT} {
 global ns av_BW Block_sess Arv_sess Active_sess
 upvar $trafname traf
   
 set Arv_sess [expr $Arv_sess + 1]
 if { $av_BW < $EquivBW } {
     # if no more available BW, block the traffic
      set started 0;  # blocked = true
      set Block_sess [expr $Block_sess + 1]
 } else {
    # traffic access OK
      set started 1;  # blocked = false
      
      set Active_sess [expr Active_sess + 1]; # increase current active conncetions number	

      set av_BW [expr $av_BW - $EquivBW]; # available BW reduce by appication equivalent bendwidth
 
      $ns at-now  "$traf start"
      #puts "sess # $Access_sess start at [$ns now], started= [$traf set started]" 
      #puts "sess # [$traf set id_] start at [$ns now], started= [$traf set started]" 

     # $ns after 0.03  "$traf start";  # 30ms delay for PDP context 30ms delay for PDP context 
     
      # only if traffic access the network, it can start and stop
      $ns at $endT   "End $traf $EquivBW "
      #$ns at [$traf set EndT]   "End $traf $EquivBW $Access_sess"  
    }

   return $started
}

proc End { traf eb } {
   global ns av_BW  Active_sess
   
   set av_BW [expr $av_BW + $eb ]; # available BW increase by appication equivalent bendwidth due to the conncetion release
   set Active_sess [expr Active_sess - 1]; # decrease current active connections number
   $ns at-now "$traf stop"
   #puts "sess # $SessID stop at [$ns now] "
}