22.1.1 Packet Traces

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

'h'

Hop: The packet started to be transmitted on the link from src_addr to dst_addr and is forwarded to the next_hop towards its dst_addr.

'r'

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

'd

Drop: The packet was dropped from queue or link from src_addr to dst_addr. 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 src_addr to dst_addr.

'-'

Leave queue: The packet left the queue from src_addr to dst_addr.

The other flags have the following meaning:

-t <time>

is the time the event occurred.

-s <src>

is the originating node.

-d <dst>

is the destination node.

-p <pkt-type>

is the descriptive name of the type of packet seen. See section 21.5 for the different types of packets supported in .

-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).

In addition to the above nam format for packet events there are nam traces that provide information about nam version, hierarchical addressing structure, node/link/queue states, node-marks, protocol states, color and annotations. These nam trace outputs typically have the following letters (or tags) as their first field and they represent the following trace types: n (node state), m (node marking), l (link state), q (queue), a (protocol state), f (protocol state variable), V (nam version), A (hierarchy information), c (nam color) and v (annotations).