This module represents the container for all X2 applications that an e/gNodeB instantiates to enable X2 communications with its peer e/gNodeBs. Specifically, for each peer, this module contains two submodules:

• a server that sends data to the peer X2App
• a client that receives data from the peer X2App

Usage diagram

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

Used in compound modules

Name	Type	Description
eNodeB	compound module	This module models an evolved Node B (eNB) of a 4G LTE network. It is a specialized device equipped with a Network Interface Card (NIC) that enables communication with the Ue devices connected to it. It serves as an access point that routes packets between the UEs and the 4G Core Network. Packets arriving from the UEs are tunneled to the appropriate next hop in the core network (e.g., the PDN Gateway, PGW) using the GPRS Tunneling Protocol (GTP). Conversely, packets received from the core network are detunneled and sent to the appropriate destination UE. In addition to the 4G NIC, this compound module includes a configurable number of wired interfaces to connect with routers of the core network or directly to the PgwStandard module, which serves as the IP module to perform forwarding, and the GtpUser module that handles GTP (de)tunneling. The latter utilizes the TrafficFlowFilter module to classify incoming packets and determine the next hop. Furthermore, it features a configurable number of LteX2App modules to facilitate peer-to-peer communications with other eNodeBs within the same LTE network.

Properties

Name	Value	Description
display	i=block/app;bgb=258,148

Gates

Name	Direction	Size	Description
sctpIn [ ]	input	2
sctpOut [ ]	output	2
x2ManagerIn	input
x2ManagerOut	output

Unassigned submodule parameters

Name	Type	Default value	Description
client.localAddress	string	""	comma separated list of addresses
client.localPort	int	0	port number to listen on
client.connectAddress	string		server address (may be symbolic)
client.connectPort	int	5000	port number to connect to
client.startTime	double	0s	time first session begins
client.numRequestsPerSession	int	1	number of requests sent per session
client.numPacketsToReceive	int	0
client.requestLength	int	1452	length of a request (bytes)
client.thinkTime	double	0s	time gap between requests
client.waitToClose	double	0s	time to wait between last message sent and abort
client.reconnectInterval	double	0s	if connection breaks, waits this much before trying to reconnect
client.inboundStreams	int	17
client.outboundStreams	int	1
client.echo	bool	false	echoes received packages when true
client.ordered	bool	true
client.queueSize	int	0
client.prMethod	int	0	0=NONE, 1=PR_TTL, 2=PR_RTX, 3=PR_PRIO, 4=PR_STRRST
client.prValue	double	0	for PR-SCTP
client.streamReset	bool	false
client.streamRequestTime	double	0s
client.streamResetType	int	5	NO_RESET=5, RESET_OUTGOING=6, RESET_INCOMING=7, RESET_BOTH=8, SSN_TSN=9
client.streamToReset	int	0
client.stopTime	double	-1s	time of finishing sending, negative values mean forever
client.primaryTime	double	0s
client.newPrimary	string	""
client.streamRequestLengths	string	""
client.streamRequestRatio	string	""
client.streamPriorities	string	""
client.finishEndsSimulation	bool	false
client.binderModule	string	"binder"
server.localAddress	string	""	comma separated list of addresses
server.localPort	int	0	port number to listen on
server.echo	bool	false	echoes received packages when true
server.echoDelay	double	0s
server.delayFirstRead	double	0s
server.readingInterval	double	0s
server.messagesToPush	int	0
server.numPacketsToSendPerClient	int	0	number of requests sent per session
server.numPacketsToReceivePerClient	int	1
server.requestLength	int	1452	length of a request (bytes)
server.thinkTime	double	0s	time gap between requests
server.waitToClose	double	0s	time to wait between last message sent and abort
server.finishEndsSimulation	bool	false
server.ordered	bool	true
server.inboundStreams	int	17
server.outboundStreams	int	1
server.queueSize	int	0
server.prMethod	int	0	0=NONE, 1=PR_TTL, 2=PR_RTX, 3=PR_PRIO, 4=PR_STRRST
server.prValue	double	0	for PR-SCTP
server.streamReset	bool	false
server.streamRequestTime	double	0s
server.streamToReset	int	0
server.streamPriorities	string	""
server.binderModule	string	"binder"

Source code

//
// This module represents the container for all X2 applications that an e/gNodeB instantiates
// to enable X2 communications with its peer e/gNodeBs. Specifically, for each peer,
// this module contains two submodules:
// - a server that sends data to the peer X2App
// - a client that receives data from the peer X2App
//
module LteX2App
{
    parameters:
        @display("i=block/app;bgb=258,148");

    gates:
        input sctpIn[2] @labels(SctpCommand/up);
        output sctpOut[2] @labels(SctpCommand/down);

        input x2ManagerIn @labels(X2Msg);
        output x2ManagerOut @labels(X2Msg);

    submodules:
        client: X2AppClient {
            @display("i=block/app;p=92,76");
        }
        server: X2AppServer {
            @display("i=block/app;p=163,76");
        }

    connections:

        //# client connections
        sctpIn[0] --> client.socketIn;
        sctpOut[0] <-- client.socketOut;

		//# server connections
        sctpIn[1] --> server.socketIn;
        sctpOut[1] <-- server.socketOut;

        //# X2 manager connections
        x2ManagerIn --> server.x2ManagerIn;
        x2ManagerOut <-- client.x2ManagerOut;
}

File: src/x2/LteX2App.ned

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