jit_1.awk

#This program is used to calculate the jitters for CBR

# jitter ＝((recvtime(j)-sendtime(j))-(recvtime(i)-sendtime(i)))/(j-i), j > i

BEGIN {

# Initialization

highest_packet_id = 0;

}


{
action = $1;
time = $2;
from = $3;
to = $4;
type = $5;
pktsize = $6;
flow_id = $8;
src = $9;
dst = $10;
seq_no = $11;
packet_id = $12;


if ( packet_id > highest_packet_id ) {
	highest_packet_id = packet_id;
  	}

#Record the transmission time


if (start_time[packet_id] == 0 ) {

# Record the sequence number

pkt_seqno[packet_id] = seq_no;
start_time[packet_id] = time;

}

#Record the receiving time for CBR (flow_id=2)

#if ( flow_id == 1 && action != "d" && from == 2) {

if ( action == "r" ) {

end_time[packet_id] = time;

}

 else {

end_time[packet_id] = -1;

}

}

END {

last_seqno = 0;

last_delay = 0;

seqno_diff = 0;


for ( packet_id = 0; packet_id <= highest_packet_id; packet_id++ ) {

start = start_time[packet_id];
end = end_time[packet_id];
packet_duration=end - start;

	if ( start < end ) {

	seqno_diff = pkt_seqno[packet_id] - last_seqno;
	delay_diff = packet_duration - last_delay;

		if (seqno_diff !=0) {
 		jitter = delay_diff/seqno_diff;
		} 
		else {
 		jitter =0;
}


last_seqno = pkt_seqno[packet_id];
last_delay = packet_duration;

	}

   }

printf("Average Jitter (CBR):\t\t%1.2f\n",jitter);
}