GtpUserX2

simple module

This module implements a simplified version of the user plane of the GPRS Tunneling Protocol (GTP) used for handover procedures. In particular, it is employed to transfer data packets from the source e/gNodeB to the target e/gNodeB during a handover (i.e., packets destined for a UE that is undergoing a handover). On one hand, this module encapsulates incoming IP datagrams from the local LteX2Manager into GTP packets and sends them over the X2 interface. On the other hand, it receives GTP packets from other e/gNodeBs and decapsulates the included IP datagrams, which are then forwarded to the local LteX2Manager.

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.

Parameters

Name	Type	Default value
binderModule	string	"binder"
localPort	int	32
tunnelPeerPort	int	32

Properties

Name	Value	Description
display	i=block/tunnel

Gates

Name	Direction	Size	Description
socketOut	output
socketIn	input
lteStackOut	output
lteStackIn	input

Source code

//
// This module implements a simplified version of the user plane of the GPRS Tunneling
// Protocol (GTP) used for handover procedures. In particular, it is employed to transfer
// data packets from the source e/gNodeB to the target e/gNodeB during a handover (i.e.,
// packets destined for a UE that is undergoing a handover).
// On one hand, this module encapsulates incoming IP datagrams from the local ~LteX2Manager
// into GTP packets and sends them over the X2 interface. On the other hand, it receives GTP
// packets from other e/gNodeBs and decapsulates the included IP datagrams, which are then
// forwarded to the local ~LteX2Manager.
//
simple GtpUserX2
{
    parameters:
        string binderModule = default("binder");

        int localPort = default(32);
        int tunnelPeerPort = default(32);

        @display("i=block/tunnel");

    gates:
        output socketOut;
        input socketIn;

        output lteStackOut;
        input lteStackIn;
}

File: src/corenetwork/gtp/GtpUserX2.ned