NS2 Trace Format

When using trace-all in NS2, a trace string is created in a trace file. The format of a trace string is shown below:



where 12 fields of the trace string are as follows.

1. Type Identifier:

• "+": a packet enque event
• "-": a packet deque event
• "r": a packet reception event
• "d": a packet drop (e.g., sent to dropHead_) event
• "c": a packet collision at the MAC level

2. Time: at which the packet tracing string is created.
3. Source Node and Destination Node: denote the IDs of the source and the destination nodes of the tracing object.
4. Packet Name: Name of the packet type
5. Packet Size: Size of the packet in bytes.
6. Flags: A 7-digit flag string

• "-": disable
• 1st = "E": ECN (Explicit Congestion Notification) echo is enabled.
• 2nd = "P": the priority in the IP header is enabled.
• 3rd : Not in use
• 4th = "A": Congestion action
• 5th = "E": Congestion has occurred.
• 6th = "F": The TCP fast start is used.
• 7th = "N": Explicit Congestion Notification (ECN) is on.

7. Flow ID
8-9. Source Address and Destination Address: the format of these two fields is "a.b", where "a" is
10. the address and "b" is the port.
11. Sequence Number
12. Packet Unique ID


For more information about tracing in NS2, see Chapter 13 in the following book from Springer:

T. Issaraiyakul and E. Hossain, "Introduction to Network Simulator NS2", Springer 2008.
http://www.springer.com/engineering/signals/book/978-0-387-71759-3

You may also find the following website useful:
http://www.ece.ubc.ca/~teerawat/NS2.htm