21.5 Packet Types

Each packet contains a packet type field used by Trace::format to print out the type of packet encountered. The type field is defined in the TraceHeader class, and is considered to be part of the trace support; it is not interpreted elsewhere in the simulator. Initialization of the type field in packets is performed by the Agent::allocpkt method. The type field is set to integer values associated with the definition passed to the Agent constructorSectionsec:agents:exlinkage. The currently-supported definitions, their values, and their associated symblic names are as follows (defined in packet.h):

enum packet_t {
	PT_TCP,
	PT_UDP,
	PT_CBR,
	PT_AUDIO,
	PT_VIDEO,
	PT_ACK,
	PT_START,
	PT_STOP,
	PT_PRUNE,
	PT_GRAFT,
	PT_GRAFTACK,
	PT_JOIN,
	PT_ASSERT,
	PT_MESSAGE,
	PT_RTCP,
	PT_RTP,
	PT_RTPROTO_DV,
	PT_CtrMcast_Encap,
	PT_CtrMcast_Decap,
	PT_SRM,
	/* simple signalling messages */
	PT_REQUEST,	
	PT_ACCEPT,	
	PT_CONFIRM,	
	PT_TEARDOWN,	
	PT_LIVE,	// packet from live network
	PT_REJECT,

	PT_TELNET,	// not needed: telnet use TCP
	PT_FTP,
	PT_PARETO,
	PT_EXP,
	PT_INVAL,
	PT_HTTP,
	/* new encapsulator */
	PT_ENCAPSULATED,
	PT_MFTP,
	/* CMU/Monarch's extnsions */
	PT_ARP,
	PT_MAC,
	PT_TORA,
	PT_DSR,
	PT_AODV,

	// insert new packet types here

	PT_NTYPE // This MUST be the LAST one
};

The constructor of class p_info glues these constants with their string values:

	p_info() {
		name_[PT_TCP]= "tcp";
		name_[PT_UDP]= "udp";
		name_[PT_CBR]= "cbr";
		name_[PT_AUDIO]= "audio";
		...
		name_[PT_NTYPE]= "undefined";
	}

See also section 11.2.2 for more details.