DropTailQueue

simple module

A limited packet queue that drops packets at the tail of the queue.

Inheritance diagram

The following diagram shows inheritance relationships for this type. Unresolved types are missing from the diagram.

Used in compound modules

Name	Type	Description
DiffservQueue	compound module	This is an example queue that can be used in interfaces of DS core and edge nodes to support the AFxy (RFC 2597) and EF (RFC 3246) PHBs.
DSQueue1	compound module	Diffserv Queue used in Experiment 1.1 - 1.6 and 5.1.
DSQueue2	compound module	Diffserv Queue used in Experiment 2.1 - 2.4.

Used in

Name	Type	Description
DropTailQueueTutorialStep	network	(no description)

Known subclasses

Name	Type	Description
EthernetQueue	compound module	Queue module that gives the PAUSE frames a higher priority.
PendingQueue	simple module	Implements a priority queue for IEEE 802.11 MAC frames. Uses a comparator to determine the order in which frames are processed. By default, prioritizes management frames over data frames, but can be configured to use different prioritization schemes such as management over multicast over unicast frames.

Extends

Name	Type	Description
PacketQueue	simple module	Implements a configurable packet queue, which is suitable for use in MAC protocols, traffic conditioning, and quality of services, among others. This is a passive component: packets are pushed into it on its input, and pulled from it on its output. This module can be used on its own, but it's also often supplemented by additional queueing components such as servers, classifiers, schedulers, multiplexers, etc. This kind of composition allows to form a larger module which can act as a packet queue with more complex behavior.

Parameters

Name	Type	Default value	Description
displayStringTextFormat	string	"contains %p pk (%l) pushed %u\npulled %o removed %r dropped %d"	Determines the text that is written on top of the submodule, supports displaying pars, watches, and module-specific information
packetCapacity	int	100	Maximum number of packets in the queue, no limit by default
dataCapacity	int	-1b	Maximum total length of packets in the queue, no limit by default
dropperClass	string	"inet::queueing::PacketAtCollectionEndDropper"	Determines which packets are dropped when the queue is overloaded, packets are not dropped by default; the parameter must be the name of a C++ class which implements the IPacketDropperFunction C++ interface and is registered via Register_Class
comparatorClass	string	""	Determines the order of packets in the queue, insertion order by default; the parameter must be the name of a C++ class which implements the IPacketComparatorFunction C++ interface and is registered via Register_Class
bufferModule	string	""	Relative module path to the IPacketBuffer module used by this queue, implicit buffer by default

Properties

Name	Value	Description
class	PacketQueue
display	i=block/queue
defaultStatistic	queueLength:vector

Gates

Name	Direction	Size	Description
in	input
out	output

Signals

Name	Type	Unit	Description
packetRemoved	inet::Packet
packetPushStarted	inet::Packet
packetDropped	inet::Packet
packetPushEnded	inet::Packet?
packetPulled	inet::Packet

Statistics

Name	Title	Source	Record	Unit	Interpolation Mode	Description
queueBitLength	queue bit length	warmup(atomic(constant0(packetPushEnded) + sum(packetLength(packetPushStarted)) - sum(packetLength(packetPulled)) - sum(packetLength(packetRemoved)) - sum(packetLength(packetDropped))))	last, max, timeavg, vector	b	sample-hold	the statistical value is the total bit length of all packets in the queue
queueLength	queue length	warmup(atomic(constant0(packetPushEnded) + count(packetPushStarted) - count(packetPulled) - count(packetRemoved) - count(packetDropped)))	last, max, timeavg, vector	pk	sample-hold	the statistical value is the number of packets in the queue
droppedPacketsQueueOverflow	dropped packets: queue overflow	packetDropReasonIsQueueOverflow(packetDropped)	count	pk	none	the statistical value is the packet that is dropped due to queue overflow
queueingTime	queueing times	queueingTime(packetPulled)	histogram, vector	s	none	the statistical value is the queueing time of packets
incomingDataRate	incoming datarate	throughput(packetPushStarted)	vector	bps	linear	the statistical value is the data rate of the incoming packets
flowQueueingTime	flow queueing times	queueingTime(demuxFlow(packetPulled))	histogram, vector	s	none	the statistical value is the flow specific queueing time of packets
incomingPacketLengths	incoming packet lengths	packetLength(packetPushStarted)	sum, histogram, vector	b	none	the statistical value is the length of the incoming packet
flowIncomingDataRate	flow specific incoming data rate	throughput(flowPacketLength(demuxFlow(packetPushStarted)))	vector	bps	linear	the statistical value is the flow specific data rate of the incoming packets
outgoingDataRate	outgoing datarate	throughput(packetPulled)	vector	bps	linear	the statistical value is the data rate of the outgoing packets
outgoingPacketLengths	outgoing packet lengths	packetLength(packetPulled)	sum, histogram, vector	b	none	the statistical value is the length of the outgoing packet
droppedPacketLengthsQueueOverflow	dropped packet lengths: queue overflow	packetLength(packetDropReasonIsQueueOverflow(packetDropped))	sum, vector	b	none	the statistical value is the length of the packet that is dropped due to queue overflow
flowOutgoingDataRate	flow specific outgoing data rate	throughput(flowPacketLength(demuxFlow(packetPulled)))	vector	bps	linear	the statistical value is the flow specific data rate of the outgoing packets
incomingPackets	incoming packets	packetPushStarted	count	pk		the statistical value is the incoming packet
outgoingPackets	outgoing packets	packetPulled	count	pk		the statistical value is the outgoing packet

Source code

//
// A limited packet queue that drops packets at the tail of the queue.
//
simple DropTailQueue extends PacketQueue
{
    parameters:
        packetCapacity = default(100);
        dropperClass = default("inet::queueing::PacketAtCollectionEndDropper");
}

File: src/inet/queueing/queue/DropTailQueue.ned