49.1.5 Packets

When a trace line describes a packet, the event type may be + (enqueue), - (dequeue), r (receive), d (drop), or h (hop).

type -t time -e extent -s source id -d destination id -c conv -i id

type is one of:

h

Hop: The packet started to be transmitted on the link from <source id> to <destination id> and is forwarded to the next hop.

r

Receive: The packet finished transmission and started to be received at the destination.

d

Drop: The packet was dropped from the queue or link from <source id> to <destination id>. Drop here doesn't distinguish between dropping from queue or link. This is decided by the drop time.

+

Enter queue: The packet entered the queue from <source id> to <destination id>.

-

Leave queue: The packet left the queue from <source id> to <destination id>.

The other flags have the following meaning:

-t <time>

is the time the event occurred.

-s <source id>

is the originating node.

-d <destination id>

is the destination node.

-p <pkt-type>

is the descriptive name of the type of packet seen. See section 26.5 for the different types of packets supported in ns.

-e <extent>

is the size (in bytes) of the packet.

-c <conv>

is the conversation id or flow-id of that session.

-i <id>

is the packet id in the conversation.

-a <attr>

is the packet attribute, which is currently used as color id.

-x <src-na.pa> <dst-sa.na> <seq> <flags> <sname>

is taken from ns-traces and it gives the source and destination node and port addresses, sequence number, flags (if any) and the type of message. For example -x {0.1 -2147483648.0 -1 ---- SRM_SESS} denotes an SRM message being sent from node 0 (port 1).

Additional flags may be added for some protocols.

-P <packet type>

gives an ASCII string specifying a comma separated list of packet types. Some values are:

TCP

A tcp data packet.

ACK

Generic acknowledgement.

NACK

Generic negative acknowledgement.

SRM

SRM data packet.

-n <sequence number>

gives the packet sequence number.