C++ definition

Accepts any number of incoming TCP connections, and sends back the data that arrives on them. The echoFactor parameter controls the amount of data to be sent back. If echoFactor==1, the received data is echoed back without change. For any other positive value of echoFactor, a message of appropriate length (datalen*echoFactor) without content (see ByteCountChunk C++ class) is sent back.

The reply can also be delayed by a constant time (echoDelay parameter).

By default, reading from the socket is not rate-limited. To allow rate limiting, set autoRead=false, and use the readSize and readDelay parameters to set a rate limit. This will allow TCP flow control to come into effect.

Compatible with both ~Ipv4 and ~Ipv6.

Inheritance diagram

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

Extends

Name	Type	Description
TcpServerHostApp	simple module	Hosts TCP-based server applications. It dynamically creates and launches a new "thread" object for each incoming connection.

Parameters

Name	Type	Default value	Description
displayStringTextFormat	string	""	Determines the text that is written on top of the submodule, supports displaying pars, watches, and module-specific information
localAddress	string	""	May be left empty ("")
localPort	int	1000	Port number to listen on
serverThreadModuleType	string	"inet.applications.tcpapp.TcpEchoAppThread"	Module type of "thread" module to launch on incoming connections
stopOperationExtraTime	double	-1s	Extra time after lifecycle stop operation finished
stopOperationTimeout	double	2s	Timeout value for lifecycle stop operation
autoRead	bool	true	Whether to use "autoread" or "explicit-read" mode for TCP connection
readSize	int	-1B	Used only with autoRead==false
readDelay	double	-1s	Used only with autoRead==false; delay for issuing a READ command after the previous READ was satisfied; -1 means immediately, 0 means zero delay
echoFactor	double	1
echoDelay	double	0s

Properties

Name	Value	Description
class	TcpEchoApp
display	i=block/app
lifecycleSupport

Gates

Name	Direction	Size	Description
socketIn	input
socketOut	output

Signals

Name	Type	Unit	Description
packetReceived	inet::Packet
packetSent	inet::Packet

Statistics

Name	Title	Source	Record	Unit	Interpolation Mode	Description
packetReceived	packets received	packetReceived	count, sum(packetBytes), vector(packetBytes)		none
packetSent	packets sent	packetSent	count, sum(packetBytes), vector(packetBytes)		none
endToEndDelay	end-to-end delay	dataAge(packetReceived)	histogram, weightedHistogram, vector	s	none

Source code

//
// Accepts any number of incoming TCP connections, and sends back the data that
// arrives on them. The `echoFactor` parameter controls the amount of data to be
// sent back. If echoFactor==1, the received data is echoed back without change.
// For any other positive value of `echoFactor`, a message of appropriate length
// (datalen*`echoFactor`) without content (see `ByteCountChunk` C++ class) is sent
// back.
//
// The reply can also be delayed by a constant time (`echoDelay` parameter).
//
// By default, reading from the socket is not rate-limited. To allow rate
// limiting, set autoRead=false, and use the `readSize` and `readDelay` parameters
// to set a rate limit. This will allow TCP flow control to come into effect.
//
// Compatible with both ~Ipv4 and ~Ipv6.
//
simple TcpEchoApp extends TcpServerHostApp
{
    parameters:
        @class(TcpEchoApp);
        bool autoRead = default(true); // Whether to use "autoread" or "explicit-read" mode for TCP connection
        volatile int readSize @unit(B) = default(-1B);    // Used only with autoRead==false
        volatile double readDelay @unit(s) = default(-1s);    // Used only with autoRead==false; delay for issuing a READ command after the previous READ was satisfied; -1 means immediately, 0 means zero delay
        double echoFactor = default(1);
        double echoDelay @unit(s) = default(0s);
        serverThreadModuleType = default("inet.applications.tcpapp.TcpEchoAppThread"); // Module type of the "thread" module to launch on incoming connections
        @signal[packetSent](type=inet::Packet);
        @signal[packetReceived](type=inet::Packet);
        @statistic[packetReceived](title="packets received"; source=packetReceived; record=count,"sum(packetBytes)","vector(packetBytes)"; interpolationmode=none);
        @statistic[packetSent](title="packets sent"; source=packetSent; record=count,"sum(packetBytes)","vector(packetBytes)"; interpolationmode=none);
        @statistic[endToEndDelay](title="end-to-end delay"; source="dataAge(packetReceived)"; unit=s; record=histogram,weightedHistogram,vector; interpolationmode=none);
}

File: src/inet/applications/tcpapp/TcpEchoApp.ned

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