Provides Ethernet 802.3 encapsulation/decapsulation and dispatching to the appropriate higher layer by DSAP values.

Expected environment:

• lowerLayerIn, lowerLayerOut gates should be connected to Ethernet EtherMAC
• upperLayerIn[], upperLayerOut[] gates should be connected to higher layer protocols or applications

Functionality:

Processes commands received from upper layers, as described in Communication between LLC and higher layers. The following commands are supported:

• IEEE802CTRL_DATA: send a frame. Encapsulates packet into EtherFrameWithLLC. This includes assigning dest address, ssap and dsap from the Ieee802Ctrl structure acompanying the message. Src address will be filled in by EtherMAC.
• IEEE802CTRL_REGISTER_DSAP: register application in LLC, as described in Application registration.
• IEEE802CTRL_DEREGISTER_DSAP: deregister application, as described in Application registration.
• IEEE802CTRL_SENDPAUSE: send PAUSE frame, as described in PAUSE frames.

Processing of packets received from the lower layers:

• decapsulate frames received from EtherMAC
• sends received frames to corresponding application, based on dsap.
• only servicetype=0 is implemented (connectionless)
• reception of non-EtherFrameWithLLC objects (e.g. EthernetIIFrame, EtherFrameWithSNAP) will cause a runtime error.

Used in compound modules

Name	Type	Description
EtherHost	compound module	An example host with one Ethernet port and a traffic generator that generates request-reply traffic directly over Ethernet. This host model does not contain higher layer protocols (IP, TCP). By default it is configured to use half-duplex MAC (CSMA/CD).

Properties

Name	Value	Description
display	i=block/fork

Gates

Name	Direction	Size	Description
upperLayerIn [ ]	input		higher layer
upperLayerOut [ ]	output		higher layer
lowerLayerIn	input		to Ethernet MAC
lowerLayerOut	output		to Ethernet MAC

Signals

Name	Type	Unit
passedUpPk	cPacket
dsap	long
droppedPkUnknownDSAP	cPacket
pauseSent	long
decapPk	cPacket
encapPk	cPacket

Statistics

Name	Title	Source	Record	Unit	Interpolation Mode
passedUpPk	packets passed up	passedUpPk	count, sum(packetBytes), vector(packetBytes)		none
dsap	dsap registering		sum, vector
droppedPkUnknownDSAP	dropped packets unknown DSAP	droppedPkUnknownDSAP	count, sum(packetBytes), vector(packetBytes)		none
pauseSent	pause sent		count, vector
decapPk	packets decapsulated	decapPk	count, sum(packetBytes), vector(packetBytes)		none
encapPk	packets encapsulated	encapPk	count, sum(packetBytes), vector(packetBytes)		none

Source code

//
// Provides Ethernet 802.3 encapsulation/decapsulation and dispatching
// to the appropriate higher layer by DSAP values.
//
// Expected environment:
// - lowerLayerIn, lowerLayerOut gates should be connected
//   to Ethernet ~EtherMAC
// - upperLayerIn[], upperLayerOut[] gates should be connected to
//   higher layer protocols or applications
//
// Functionality:
//
// Processes commands received from upper layers, as described in
// <a href="llc-app.html">Communication between LLC and higher layers</a>.
// The following commands are supported:
// - IEEE802CTRL_DATA: send a frame.
//   Encapsulates packet into ~EtherFrameWithLLC. This includes assigning
//   dest address, ssap and dsap from the ~Ieee802Ctrl structure acompanying
//   the message. Src address will be filled in by ~EtherMAC.
// - IEEE802CTRL_REGISTER_DSAP: register application in LLC, as described in
//   <a href="appreg.html">Application registration</a>.
// - IEEE802CTRL_DEREGISTER_DSAP: deregister application, as described in
//   <a href="appreg.html">Application registration</a>.
// - IEEE802CTRL_SENDPAUSE: send PAUSE frame, as described in
//   <a href="ether-pause.html">PAUSE frames</a>.
//
// Processing of packets received from the lower layers:
// - decapsulate frames received from ~EtherMAC
// - sends received frames to corresponding application, based on dsap.
// - only servicetype=0 is implemented (connectionless)
// - reception of non-~EtherFrameWithLLC objects (e.g. ~EthernetIIFrame,
//   ~EtherFrameWithSNAP) will cause a runtime error.
//
simple EtherLLC
{
    parameters:
        @display("i=block/fork");

        @signal[dsap](type=long);
        @signal[encapPk](type=cPacket);
        @signal[decapPk](type=cPacket);
        @signal[passedUpPk](type=cPacket);
        @signal[droppedPkUnknownDSAP](type=cPacket);
        @signal[pauseSent](type=long); // pause units
        @statistic[dsap](title="dsap registering"; record=sum,vector);
        @statistic[encapPk](title="packets encapsulated"; source=encapPk; record=count,"sum(packetBytes)","vector(packetBytes)"; interpolationmode=none);
        @statistic[decapPk](title="packets decapsulated"; source=decapPk; record=count,"sum(packetBytes)","vector(packetBytes)"; interpolationmode=none);
        @statistic[passedUpPk](title="packets passed up"; source=passedUpPk; record=count,"sum(packetBytes)","vector(packetBytes)"; interpolationmode=none);
        @statistic[droppedPkUnknownDSAP](title="dropped packets unknown DSAP"; source=droppedPkUnknownDSAP; record=count,"sum(packetBytes)","vector(packetBytes)"; interpolationmode=none);
        @statistic[pauseSent](title="pause sent"; record=count,vector);
    gates:
        input upperLayerIn[] @labels(Ieee802Ctrl/down); // higher layer
        output upperLayerOut[] @labels(Ieee802Ctrl/up); // higher layer
        input lowerLayerIn @labels(EtherFrame);     // to Ethernet MAC
        output lowerLayerOut @labels(EtherFrame);   // to Ethernet MAC
}

File: src/inet/linklayer/ethernet/EtherLLC.ned

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