/** Groups packets into Burst Collections */
private void groupIntoBursts() {
// Validate that there are packets
List<PacketInfo> packets = this.analysis.getPackets();
if (packets.size() <= 0) {
this.burstCollection = Collections.emptyList();
return;
}
ArrayList<Burst> result = new ArrayList<Burst>();
double burstThresh = profile.getBurstTh();
double longBurstThresh = profile.getLongBurstTh();
List<PacketInfo> burstPackets = new ArrayList<PacketInfo>();
// Step 1: Build bursts using burst time threshold
PacketInfo lastPacket = null;
for (PacketInfo packet : packets) {
if (lastPacket == null
|| (packet.getTimeStamp() - lastPacket.getTimeStamp() > burstThresh
&& !mss.contains(lastPacket.getPayloadLen()))) {
if (burstPackets.size() > 0) {
result.add(new Burst(burstPackets));
burstPackets.clear();
}
}
burstPackets.add(packet);
lastPacket = packet;
}
result.add(new Burst(burstPackets));
// Step 2: Remove promotion delays and merge bursts if possible
Map<PacketInfo, Double> timestampList = normalizeCore(packets);
List<Burst> newBurstColl = new ArrayList<Burst>(result.size());
int n = result.size();
Burst newBurst = result.get(0);
for (int i = 0; i < n - 1; i++) {
Burst bnext = result.get(i + 1);
double time1 = timestampList.get(newBurst.getEndPacket());
double time2 = timestampList.get(bnext.getBeginPacket());
if ((time2 - time1) < burstThresh) {
newBurst.merge(bnext);
} else {
newBurstColl.add(newBurst);
newBurst = bnext;
}
}
newBurstColl.add(newBurst);
this.burstCollection = newBurstColl;
// Step 3: compute burstID for each packet
n = burstCollection.size();
for (Burst b : burstCollection) {
for (PacketInfo p : b.getPackets()) {
p.setBurst(b);
}
}
// Step 4: determine short/long IBTs
n = burstCollection.size();
for (int i = 0; i < n; i++) {
Burst b = burstCollection.get(i);
assert (b.getEndTime() >= b.getBeginTime());
if (i < n - 1) {
double ibt = burstCollection.get(i + 1).getBeginTime() - b.getEndTime();
assert (ibt >= burstThresh);
b.setbLong((ibt > longBurstThresh));
} else {
b.setbLong(true);
}
}
}
