Ns-2 CMU Trace Analysis

[ Introduction | Trace example | Measure throughput & delay | Back to Network Simulator 2 for Wireless ]
Ns-2 has two options to generate traces with different fomats. Basically, you could use 
$ns use-newtrace
to generate the new trace and the detailed explanation could be found in Ns Manual. A very good reference about the trace is the ns-2 wiki page. See: http://nsnam.isi.edu/nsnam/index.php/NS-2_Trace_Formats

By default, old trace format is used. The source code ./trace/cmu-trace.cc needs to be read to understand it completely. For instance, the function format_ip will explain the trace of IP part.
void
CMUTrace::format_ip(Packet *p, int offset)
{
        struct hdr_cmn *ch = HDR_CMN(p);
        struct hdr_ip *ih = HDR_IP(p);

        // hack the IP address to convert pkt format to hostid format
        // for now until port ids are removed from IP address. -Padma.
        int src = Address::instance().get_nodeaddr(ih->saddr());
        int dst = Address::instance().get_nodeaddr(ih->daddr());

    ............

}

void
CMUTrace::format_mac(Packet *p, int offset)
{

else {
                sprintf(pt_->buffer() + offset,
                        " [%x %x %x %x] ",
                        //*((u_int16_t*) &mh->dh_fc),
                        mh->dh_duration,

                        ETHER_ADDR(mh->dh_ra),
                        ETHER_ADDR(mh->dh_ta),


                        GET_ETHER_TYPE(mh->dh_body));
        }
......

}


A typical trace for a CBR traffic is:

s 20.000000000 _0_ AGT  --- 6 cbr 512 [0 0 0 0] ------- [0:0 1:0 32 0] [0] 0 0
r 20.000000000 _0_ RTR  --- 6 cbr 512 [0 0 0 0] ------- [0:0 1:0 32 0] [0] 0 0
s 20.000000000 _0_ RTR  --- 6 cbr 532 [0 0 0 0] ------- [0:0 1:0 32 1] [0] 0 0
s 20.000275000 _0_ MAC  --- 6 cbr 584 [13a 1 0 800] ------- [0:0 1:0 32 1] [0] 0 0
r 20.004947063 _1_ MAC  --- 6 cbr 532 [13a 1 0 800] ------- [0:0 1:0 32 1] [0] 1 0
s 20.004957063 _1_ MAC  --- 0 ACK 38 [0 0 0 0]
r 20.004972063 _1_ AGT  --- 6 cbr 532 [13a 1 0 800] ------- [0:0 1:0 32 1] [0] 1 0
r 20.005261125 _0_ MAC  --- 0 ACK 38 [0 0 0 0]

An AWK script example to analyze the trace and calculate throughput
   
For a topology involve 4 flows with distinguishing source and destination nodes, this following awk script gets throughout data and put in wu.dat file
BEGIN {counter1 = 0; counter2 = 0; counter3 = 0; counter4 = 0;}
$1~/r/ && $2>50 && $2< 100  && /_12_/ && /AGT/  {   counter1 += ($8- 20)
                        size = $8 - 20 }
$1~/r/ && $2>50 && $2 <100 && /_13_/ && /AGT/  {   counter2 += ($8- 20)
                        size = $8 - 20 }
$1~/r/ && $2>50 && $2<100 && /_14_/ && /AGT/  {   counter3 += ($8- 20)
                        size = $8 - 20 }
$1~/r/ && $2>50 && $2<100 && /_15_/ && /AGT/  {   counter4 += ($8- 20)
                        size = $8 - 20 } throughout

END {
      print (size , counter1*8/(50), counter2*8/50, counter3*8/(50), counter4*8/50,
                  (counter1+counter2+counter3+counter4)*8/50 )  >> "wu.dat"}

To analyze the throughout or delay in a finite time duration, we need extract sending and receiving time from the trace file

$2>100 && $2 < 150 && (/_6_/ || /_2_/)  &&  /AGT/    {  print $1, $2, $6  > "dst2.tr" }
$2>100 && $2 <150 && (/_0_/ || /_9_/)  &&  /AGT/    {   print $1, $2, $6  > "dst9.tr" }
$2>100 && $2 <150 && (/_12_/ || /_3_/)  &&  /AGT/    {   print $1, $2, $6  > "dst3.tr" }
$2>100 && $2 <150 && (/_10_/ || /_4_/)  &&  /AGT/    {   print $1, $2, $6  > "dst4.tr" }
$2>100 && $2 <150 && (/_11_/ || /_8_/)  &&  /AGT/    {   print $1, $2, $6  > "dst8.tr" }

The respective new trace files such as "dst2.tr" will keep the sending or receiving time, "s'" or "r" label and, node's MAC address. From those data, we could use a program to calculate the average throughput or mean value of end-to-end delay of the flow.

The C source file to calcualte delay can be downloaded here:

To use this C code:
$ gcc delay.c -o delaycal
$ ./delaycal dst2.tr wu0.dat wu1.dat