Wednesday, December 29, 2010

NS-2 Trace format

1.     Type Identifier:-
"+": a packet enque event
"-": a packet deque event
"r": a packet reception event
"d": a packet drop
"c": a packet collision at the MAC level

2.     Time:- Time at which the above event occurred.

3.     Source and Destination Node: - It shows the ID of the nodes between which the event has occurred.

4.      Packet Name:- Type of packet

5.     Packet Size: - Size of the packet in bytes.

6.     Flags: - A 7-digit flag string is defined. Each flag digit is set to “-” if the corresponding flag is disabled. Otherwise, it will be set as follows. The first is set to “E” if an ECN (Explicit Congestion Notification) echo is enabled. The second is set to “P” if the priority in the IP header is enabled. The fourth is set to “A” if the corresponding TCP takes an action on congestion (e.g., closes the congestion window). The fifth is set to “E” if the congestion has occurred. The sixth is set to “F” if the TCP fast start is used. Finally, the seventh is set to “N”, when the transport layer protocol is capable of using Explicit Congestion Notification (ECN).

7.     Flow ID: Flow ID specified in the field fid_ of an IP packet header.

8.     Source Address and Destination Address: The source and destination addresses of a packet specified in an IP packet header. For a flat addressing scheme, the format of these two fields is “a.b”, where “a” is the address and “b” is the port.

9.     Sequence Number: The sequence number specified in packet header. Specified by a transport layer protocol.

10  Packet Unique ID: A unique ID stored in a common packet header.

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