Simple Module TCPSessionApp

C++ definition

Single-connection TCP application: it opens a connection, sends the given number of bytes, and closes. Sending may be one-off, or may be controlled by a "script" which is a series of (time, number of bytes) pairs. May act either as client or as server, and works with TCPVirtualBytesSendQueue/RcvQueue as sendQueue/receiveQueue setting for TCP. Compatible with both IPv4 (IPv4) and IPv6.

Opening the connection

Regarding the type of opening the connection, the application may be either a client or a server. When active=false, the application will listen on the given local localPort, and wait for an incoming connection. When active=true, the application will bind to given local localAddress:localPort, and connect to the connectAddress:connectPort. To use an ephemeral port as local port, set the localPort parameter to -1.

Even when in server mode (active=false), the application will only serve one incoming connection. Further connect attempts will be refused by TCP (it will send RST) for lack of LISTENing connections.

The time of opening the connection is in the tOpen parameter.

Sending data

Regardless of the type of OPEN, the application can be made to send data. One way of specifying sending is via the tSend, sendBytes parameters, the other way is sendScript. With the former, sendBytes bytes will be sent at tSend. With sendScript, the format is "<time> <numBytes>;<time> <numBytes>;..."

Closing the connection

The application will issue a TCP CLOSE at time tClose. If tClose=-1, no CLOSE will be issued.

Configuring App

The module parameter dataTransferMode should be set the transfer mode in TCP layer. Currently you have three choices:

1. set them to "bytecount". This mode manages "virtual bytes", that is, only byte counts are transmitted over the TCP connection and no actual data. cMessage contents, and even message boundaries are not preserved with these classes: for example, if the client sends a single cMessage with length = 1 megabyte over TCP, the receiver-side client will see a sequence of MSS-sized messages.
2. use "object", which transmits cMessage objects (and subclasses) over a TCP connection. The same message object sequence that was sent by the client to the sender-side TCP entity will be reproduced on the receiver side. If a client sends a cMessage with length = 1 megabyte, the receiver-side client will receive the same message object (or a clone) after the TCP entities have completed simulating the transmission of 1 megabyte over the connection. This is a different behaviour from TCPVirtualDataSendQueue/RcvQueue. This mode is not implemented in TCP_NSC yet.
3. use "bytestream", which transmits real bytes of messages.

Usage diagram:

The following diagram shows usage relationships between types. Unresolved types are missing from the diagram.

Inheritance diagram:

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

Parameters:

Properties:

Gates:

Signals:

Statistics:

Source code:

//
// Single-connection TCP application: it opens a connection, sends
// the given number of bytes, and closes. Sending may be one-off,
// or may be controlled by a "script" which is a series of
// (time, number of bytes) pairs. May act either as client or as server,
// and works with TCPVirtualBytesSendQueue/RcvQueue as sendQueue/receiveQueue
// setting for ~TCP.
// Compatible with both IPv4 (~IPv4) and ~IPv6.
//
// <b>Opening the connection</b>
//
// Regarding the type of opening the connection, the application may
// be either a client or a server. When active=false, the application
// will listen on the given local localPort, and wait for an incoming connection.
// When active=true, the application will bind to given local localAddress:localPort,
// and connect to the connectAddress:connectPort. To use an ephemeral port
// as local port, set the localPort parameter to -1.
//
// Even when in server mode (active=false), the application will only
// serve one incoming connection. Further connect attempts will be
// refused by TCP (it will send RST) for lack of LISTENing connections.
//
// The time of opening the connection is in the tOpen parameter.
//
// <b>Sending data</b>
//
// Regardless of the type of OPEN, the application can be made to send
// data. One way of specifying sending is via the tSend, sendBytes
// parameters, the other way is sendScript. With the former, sendBytes
// bytes will be sent at tSend. With sendScript, the format is
// "<time> <numBytes>;<time> <numBytes>;..."
//
// <b>Closing the connection</b>
//
// The application will issue a TCP CLOSE at time tClose. If tClose=-1, no
// CLOSE will be issued.
//
// <b>Configuring App</b>
//
// The module parameter dataTransferMode should be set the transfer mode in TCP layer.
// Currently you have three choices:
//
//   -# set them to "bytecount".
//      This mode manages "virtual bytes", that is, only byte counts are
//      transmitted over the TCP connection and no actual data. cMessage
//      contents, and even message boundaries are not preserved with these
//      classes: for example, if the client sends a single cMessage with
//      length = 1 megabyte over TCP, the receiver-side client will see a
//      sequence of MSS-sized messages.
//
//   -# use "object", which transmits
//      cMessage objects (and subclasses) over a TCP connection. The same
//      message object sequence that was sent by the client to the
//      sender-side TCP entity will be reproduced on the receiver side.
//      If a client sends a cMessage with length = 1 megabyte, the
//      receiver-side client will receive the same message object (or a clone)
//      after the TCP entities have completed simulating the transmission
//      of 1 megabyte over the connection. This is a different behaviour
//      from TCPVirtualDataSendQueue/RcvQueue.
//      This mode is not implemented in ~TCP_NSC yet.
//
//   -# use "bytestream", which transmits real bytes of messages.
//
simple TCPSessionApp like ITCPApp
{
    parameters:
        string localAddress = default("");
        int localPort = default(-1);  // local port
        bool active = default(true);
        string connectAddress;
        int connectPort = default(1000);
        string dataTransferMode @enum("bytecount","object","bytestream") = default("bytecount");
        double tOpen @unit(s) = default(1s);
        double tSend @unit(s) = default(1s);
        int sendBytes @unit(B) = default(1MiB);
        string sendScript = default("");
        double tClose @unit(s) = default(2s);
        @display("i=block/app");
        @signal[connect](type=long);
        @signal[sentPk](type=cPacket);
        @signal[rcvdPk](type=cPacket);
        @statistic[rcvdPk](title="packets received"; source=rcvdPk; record=count,"sum(packetBytes)","vector(packetBytes)"; interpolationmode=none);
        @statistic[sentPk](title="packets sent"; source=sentPk; record=count,"sum(packetBytes)","vector(packetBytes)"; interpolationmode=none);
        @statistic[endToEndDelay](title="end-to-end delay"; source="messageAge(rcvdPk)"; unit=s; record=histogram,vector; interpolationmode=none);
    gates:
        input tcpIn @labels(TCPCommand/up);
        output tcpOut @labels(TCPCommand/down);
}

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