Represents the Virtualisation Infrastructure in a MEC host. It takes care of forwarding packets coming from the 5G core network to the appropriate MEC applications, applying the processing required by all the necessary network protocol layers. Optionally, it can host "independent" MEC applications, i.e., applications that are statically created at initialization, without going through the normal lifecycle (i.e., through the UALCMP and MEC orchestrator). It provides the external interface to communicate with emulated MEC applications, running outside the simulation environment.

Usage diagram

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

Used in compound modules

Name	Type	Description
MecHost	compound module	Represents a model of a Multi-access Edge Computing (MEC) host belonging to a MEC system, as specified by the ETSI GS MEC 003 specifications. It runs MEC applications within its VirtualisationInfrastructure and can provide a number of MEC services via the MEC platform. MEC applications can be created either dynamically by the MEC orchestrator or statically at the initialization of the simulation. The MEC host possesses a configurable number of computing resources (such as CPU speed, RAM, and storage) and keeps track of the utilization of these resources by the MEC applications via the VirtualisationInfrastructureManager. Moreover, this module includes a User Plane Function (UPF) that allows it to be connected with the 5G core network.

Parameters

Name	Type	Default value	Description
hasIpv4	bool	true
hasIpv6	bool	false
numIndependentMecApp	int	0
numExtEthInterfaces	int	0
gateway	string	""

Properties

Name	Value	Description
networkNode
display	bgb=1350,750;i=block/dispatch

Gates

Name	Direction	Size	Description
ppp [ ]	inout		Connection with GtpEndpoint and local/external networks
independentMecAppOut [ ]	output	numIndependentMecApp	Connection to the ME App input gate
independentMecAppIn [ ]	input	numIndependentMecApp	Connection to the ME App output gate
meAppOut [ ]	output		Connection to the ME App input gate
meAppIn [ ]	input		Connection to the ME App output gate
mecPlatform [ ]	inout		Connection to the MEC Platform

Unassigned submodule parameters

Name	Type	Default value	Description
interfaceTable.displayStringTextFormat	string	"{numInterfaces} interfaces"	Determines the text that is written on top of the submodule, supports displaying pars, watches, and module-specific information
interfaceTable.displayAddresses	bool	false	Whether to display IP addresses on links
pppIf.pcapRecorder.displayStringTextFormat	string	"rec: %n pks"	Determines the text that is written on top of the submodule, supports displaying pars, watches, and module-specific information
pppIf.pcapRecorder.verbose	bool	true	Whether to log packets on the module output
pppIf.pcapRecorder.recordEmptyPackets	bool	true	Specifies if zero length packets are recorded or not
pppIf.pcapRecorder.enableConvertingPackets	bool	true	Specifies if converting packets to link type is allowed or not
pppIf.pcapRecorder.pcapFile	string	""	The PCAP file to be written, suggested value: pcapFile = "${resultdir}/${configname}-#${runnumber}" + fullpath() + ".pcap"
pppIf.pcapRecorder.fileFormat	string	"pcapng"
pppIf.pcapRecorder.snaplen	int	65535	Maximum number of bytes to record per packet
pppIf.pcapRecorder.timePrecision	int	6	Time precision in recorded file. pcap supports only 6 (usec) or 9 (nanosec), pcapng supports more values (see 'if_tsresol' option in pcapng file format).
pppIf.pcapRecorder.dumpBadFrames	bool	true	Enable dump of frames with hasBitError
pppIf.pcapRecorder.sendingSignalNames	string	"transmissionEnded"	Space-separated list of outbound packet signals to subscribe to
pppIf.pcapRecorder.receivingSignalNames	string	"receptionEnded"	Space-separated list of inbound packet signals to subscribe to
pppIf.pcapRecorder.dumpProtocols	string	"ethernetmac ppp ieee80211mac"	Space-separated list of protocol names as defined in the Protocol class
pppIf.pcapRecorder.packetFilter	object	"*"	Which packets are considered, matches all packets by default
pppIf.pcapRecorder.helpers	string	""	Usable PcapRecorder::IHelper helpers for accept packettype and store/convert packet as specified linktype currently available: "inet::AckingMacToEthernetPcapRecorderHelper"
pppIf.pcapRecorder.alwaysFlush	bool	false	Flush the pcapFile after each write to ensure that all packets are captured in case of a crash
pppIf.ppp.displayStringTextFormat	string	"rate: %b\nsent: %s, rcvd: %r\nqueue: %q, drop: %d"	Determines the text that is written on top of the submodule, supports displaying pars, watches, and module-specific information
pppIf.ppp.interfaceTableModule	string		The path to the InterfaceTable module
pppIf.ppp.sendRawBytes	bool	false	When true packets are serialized into a sequence of bytes before sending out
pppIf.ppp.mtu	int	4470B
pppIf.ppp.stopOperationExtraTime	double	-1s	Extra time after lifecycle stop operation finished
pppIf.ppp.stopOperationTimeout	double	2s	Timeout value for lifecycle stop operation
extEth.bitrate	double
udp.displayStringTextFormat	string	"passed up: {numPassedUp} pks\nsent: {numSent} pks{udpDroppedText}"	Determines the text that is written on top of the submodule, supports displaying pars, watches, and module-specific information
udp.interfaceTableModule	string		The path to the InterfaceTable module
udp.checksumMode	string	"declared"
udp.defaultMulticastLoop	bool	true
tcp.displayStringTextFormat	string	""	Determines the text that is written on top of the submodule, supports displaying pars, watches, and module-specific information
tcp.checksumMode	string	"declared"
tcp.advertisedWindow	int	14 * this.mss	In bytes, corresponds with the maximal receiver buffer capacity (Note: normally, NIC queues should be at least this size)
tcp.delayedAcksEnabled	bool	false	Delayed ACK algorithm (RFC 1122) enabled/disabled
tcp.nagleEnabled	bool	true	Nagle's algorithm (RFC 896) enabled/disabled
tcp.limitedTransmitEnabled	bool	false	Limited Transmit algorithm (RFC 3042) enabled/disabled (can be used for TcpReno/TcpTahoe/TcpNewReno/TcpNoCongestionControl)
tcp.increasedIWEnabled	bool	false	Increased Initial Window (RFC 3390) enabled/disabled
tcp.sackSupport	bool	false	Selective Acknowledgment (RFC 2018, 2883, 3517) support (header option) (SACK will be enabled for a connection if both endpoints support it)
tcp.windowScalingSupport	bool	false	Window Scale (RFC 1323) support (header option) (WS will be enabled for a connection if both endpoints support it)
tcp.windowScalingFactor	int	-1	Window Scaling Factor given as a shift count. Valid values are 0..14, and -1 for automatic selection (it chooses the smallest shift count that makes advertisedWindow representable in 16 bits)
tcp.timestampSupport	bool	false	Timestamps (RFC 1323) support (header option) (TS will be enabled for a connection if both endpoints support it)
tcp.mss	int	536	Maximum Segment Size (header option). Default 536 per RFC 1122.
tcp.msl	int	120s	Maximum Segment Lifetime
tcp.tcpAlgorithmClass	string	"TcpReno"
tcp.dupthresh	int	3	Used for TcpTahoe, TcpReno, and SACK (RFC 3517) DO NOT change unless you really know what you are doing
tcp.initialSsthresh	int	0xFFFFFFFF	Initial value for Slow Start threshold used in TahoeRenoFamily. The initial value of ssthresh SHOULD be set arbitrarily high (e.g., to the size of the largest possible advertised window) Without user interaction there is no limit...
tcp.stopOperationExtraTime	double	0s	Extra time after lifecycle stop operation finished
tcp.stopOperationTimeout	double	2s	Timeout value for lifecycle stop operation
tcp.ecnWillingness	bool	false	True if willing to use ECN
tcp.dctcpGamma	double	0.0625	A fixed estimation gain for calculating dctcp_alpha (RFC 8257 4.2)
tcp.pmtudEnabled	bool	false	Path MTU Discovery (RFC 1191, RFC 1981) enabled/disabled
tcp.pmtudTimeout	double	600s	Time after which the original MSS is restored to probe for increased path MTU (RFC 1191, Section 6.3)
at.displayStringTextFormat	string	"processed {numProcessedPackets} pk ({processedTotalLength})"	Determines the text that is written on top of the submodule, supports displaying pars, watches, and module-specific information
at.interfaceTableModule	string		Module path to the InterfaceTable module
at.forwardServiceRegistration	bool	true
at.forwardProtocolRegistration	bool	true
at.interfaceMapping	object	{}	Maps network interface names to connected submodule names (e.g. {"eth0": "bridging"}), overrides automatically learned dispatching; * overrides all learned network interfaces, ? overrides default
at.serviceMapping	object	{}	Maps protocols to connected submodule names (e.g. {"ethernetmac": "bridging"}), overrides automatically learned dispatching; * overrides all learned services, ? overrides default
at.protocolMapping	object	{}	Maps protocols to connected submodule names (e.g. {"ipv4": "bridging"}), overrides automatically learned dispatching; * overrides all learned protocols, ? overrides default
tn.displayStringTextFormat	string	"processed {numProcessedPackets} pk ({processedTotalLength})"	Determines the text that is written on top of the submodule, supports displaying pars, watches, and module-specific information
tn.interfaceTableModule	string		Module path to the InterfaceTable module
tn.forwardServiceRegistration	bool	true
tn.forwardProtocolRegistration	bool	true
tn.interfaceMapping	object	{}	Maps network interface names to connected submodule names (e.g. {"eth0": "bridging"}), overrides automatically learned dispatching; * overrides all learned network interfaces, ? overrides default
tn.serviceMapping	object	{}	Maps protocols to connected submodule names (e.g. {"ethernetmac": "bridging"}), overrides automatically learned dispatching; * overrides all learned services, ? overrides default
tn.protocolMapping	object	{}	Maps protocols to connected submodule names (e.g. {"ipv4": "bridging"}), overrides automatically learned dispatching; * overrides all learned protocols, ? overrides default
nl.displayStringTextFormat	string	"processed {numProcessedPackets} pk ({processedTotalLength})"	Determines the text that is written on top of the submodule, supports displaying pars, watches, and module-specific information
nl.interfaceTableModule	string		Module path to the InterfaceTable module
nl.forwardServiceRegistration	bool	true
nl.forwardProtocolRegistration	bool	true
nl.interfaceMapping	object	{}	Maps network interface names to connected submodule names (e.g. {"eth0": "bridging"}), overrides automatically learned dispatching; * overrides all learned network interfaces, ? overrides default
nl.serviceMapping	object	{}	Maps protocols to connected submodule names (e.g. {"ethernetmac": "bridging"}), overrides automatically learned dispatching; * overrides all learned services, ? overrides default
nl.protocolMapping	object	{}	Maps protocols to connected submodule names (e.g. {"ipv4": "bridging"}), overrides automatically learned dispatching; * overrides all learned protocols, ? overrides default

Source code

//
// Represents the Virtualisation Infrastructure in a MEC host.
// It takes care of forwarding packets coming from the 5G core network to the
// appropriate MEC applications, applying the processing required by all the necessary
// network protocol layers.
// Optionally, it can host "independent" MEC applications, i.e., applications that
// are statically created at initialization, without going through the normal
// lifecycle (i.e., through the UALCMP and MEC orchestrator).
// It provides the external interface to communicate with emulated MEC applications,
// running outside the simulation environment.
//
module VirtualisationInfrastructure
{
    parameters:
        @networkNode();
        @display("bgb=1350,750;i=block/dispatch");
        @figure[applicationLayer](type=rectangle; pos=250,6; size=600,130; lineColor=#808080; cornerRadius=5; fillColor=#ffff00; fillOpacity=0.1);
        @figure[applicationLayer.title](type=text; pos=845,11; anchor=ne; text="application layer");
        @figure[transportLayer](type=rectangle; pos=250,156; size=600,130; fillColor=#ff0000; lineColor=#808080; cornerRadius=5; fillOpacity=0.1);
        @figure[transportLayer.title](type=text; pos=845,161; anchor=ne; text="transport layer");
        @figure[networkLayer](type=rectangle; pos=250,306; size=600,130; fillColor=#00ff00; lineColor=#808080; cornerRadius=5; fillOpacity=0.1);
        @figure[networkLayer.title](type=text; pos=845,311; anchor=ne; text="network layer");
        @figure[linkLayer](type=rectangle; pos=250,456; size=600,130; fillColor=#0000ff; lineColor=#808080; cornerRadius=5; fillOpacity=0.1);
        @figure[linkLayer.title](type=text; pos=845,461; anchor=ne; text="link layer");
        @figure[submodules];

        //# Network Layer specs
        bool hasIpv4 = default(true);
        bool hasIpv6 = default(false);
        *.interfaceTableModule = default(absPath(".interfaceTable"));
        *.routingTableModule = default("^.ipv4.routingTable");

        int numIndependentMecApp = default(0);
        int numExtEthInterfaces = default(0);
        string gateway = default("");

    gates:
        inout ppp[];				// Connection with GtpEndpoint and local/external networks

        output independentMecAppOut[numIndependentMecApp];			// Connection to the ME App input gate
        input independentMecAppIn[numIndependentMecApp];			// Connection to the ME App output gate

        output meAppOut[];			// Connection to the ME App input gate
        input meAppIn[];			// Connection to the ME App output gate

        inout mecPlatform[];			// Connection to the MEC Platform

    submodules:

        interfaceTable: InterfaceTable {
            @display("p=61,74;is=s");
        }

        //#
        //# link-layer modules
        //#
        pppIf[sizeof(ppp)]: PppInterface {
            @display("p=736,660");
        }

        // ethernet interface used for communicating with external applications in emulation mode
        extEth[numExtEthInterfaces]: <default("ExtLowerEthernetInterface")> like IEthernetInterface {
            parameters:
                @display("p=326,660,row,150;q=txQueue");
        }
        encap: <default("EthernetEncapsulation")> like IEthernetLayer if typename != "" {
            parameters:
                registerProtocol = true;
                @display("p=326,511");
        }

        lo: <default("LoopbackInterface")> like ILoopbackInterface {
            parameters:
                @display("p=548,660,row,150");
        }

        //#
        //# Network layer module
        //#
        ipv4: <default("Ipv4NetworkLayer")> like INetworkLayer if hasIpv4 {
            parameters:
                @display("p=420,372;q=queue");
        }
        ipv6: <default("Ipv6NetworkLayer")> like INetworkLayer if hasIpv6 {
            parameters:
                @display("p=657,374;q=queue");
        }

        //#
        //# Transport layer modules and corresponding application modules
        //#
        udp: Udp {
            @display("p=460,217");
        }

        tcp: Tcp {
            @display("p=627,217");
        }

        // message dispatcher for SAP between application and transport layer
        at: MessageDispatcher {
            parameters:
                @display("p=550,146;b=600,5,,,,1");
        }
        // message dispatcher for SAP between transport and network layer
        tn: MessageDispatcher {
            parameters:
                @display("p=550,300;b=600,5,,,,1");
        }
        // message dispatcher for SAP to link layer
        nl: MessageDispatcher {
            parameters:
                @display("p=550,446;b=600,5,,,,1");
        }

    connections allowunconnected:

        for i=0..numIndependentMecApp -1 {
            at.out++ --> independentMecAppOut++;
            at.in++ <-- independentMecAppIn++;
        }

        for i=0..sizeof(mecPlatform)-1 {
            at.out++ --> mecPlatform$o[i];
            at.in++ <-- mecPlatform$i[i];
        }

        //#
        //# App layer to transport layer connections
        //#
        at.out++ --> udp.appIn;
        at.in++ <-- udp.appOut;

        at.out++ --> tcp.appIn;
        at.in++ <-- tcp.appOut;


        //#
        //# Transport layer to network layer connections
        //#
        udp.ipOut --> tn.in++;
        udp.ipIn <-- tn.out++;

        tcp.ipOut --> tn.in++;
        tcp.ipIn <-- tn.out++;


        ipv4.ifIn <-- nl.out++ if hasIpv4;
        ipv4.ifOut --> nl.in++ if hasIpv4;

        ipv4.transportIn <-- tn.out++ if hasIpv4;
        ipv4.transportOut --> tn.in++ if hasIpv4;

        //#
        //# Network layer to link layer connections
        //#
        ipv6.ifIn <-- nl.out++ if hasIpv6;
        ipv6.ifOut --> nl.in++ if hasIpv6;

        ipv6.transportIn <-- tn.out++ if hasIpv6;
        ipv6.transportOut --> tn.in++ if hasIpv6;

        for i=0..sizeof(ppp)-1 {
            pppIf[i].upperLayerOut --> nl.in++;
            pppIf[i].upperLayerIn <-- nl.out++;
            pppIf[i].phys <--> ppp++;
        }

        for i=0..numExtEthInterfaces-1 {
            encap.lowerLayerOut --> extEth[i].upperLayerIn;
            encap.lowerLayerIn <-- extEth[i].upperLayerOut;
        }
        encap.upperLayerOut --> nl.in++ if numExtEthInterfaces != 0;
        encap.upperLayerIn <-- nl.out++ if numExtEthInterfaces != 0;

        nl.out++ --> lo.upperLayerIn;
        lo.upperLayerOut --> nl.in++;
}

File: src/simu5g/mec/vi/VirtualisationInfrastructure.ned

---

This documentation is released under the Creative Commons license