DESCRIPTION

This is a basic implementation of Ethernet Passive Optical Network. OLT and ONU modules are defined and they both support one or multiple LLIDs. MPCP protocol has been implemented on OLT and ONU models to assign LLIDs dynamically. The devices are implemented in a structured way per network Layer and basic goal is to keep them extensible. Different Queue Management, Relay and traffic classification modules should be easily integrated into the existing devices using the same MAC and MAC Control Layers.

Preview

FEATURES

PON_Splitter

Simple passive splitting. On collision, the module discards the second frame while the first one has already been transmitted. Also it counts upstream and downstream collisions. This should actually never happen, but is really useful if you want to change the TDMA functions.

MPCP Protocol implementation

The current implementation varies a bit from the RFCs on the registration process. It currently send the GATE message AFTER the ONU acknowledgment, while the drafts say that the GATE should be sent right after the REGISTER message. This way we avoid allocating resources for an ONU that may not send ACK message later. Actually it just simplifies the upstream bandwidth allocation.

Layers

MAC: A copy of the INET MAC layer with some changes. First it sends messages of type EtherFrameWithLLID, which are actually Ethernet frames but in the preamble they include the LLID. So EPON_PREAMBLE_BYTES is now (7 - 2) and the frame structure is changed. These frames encapsulate the real Ethernet ones. Second, when the interface is IDLE and wakes-up it _will_ wait for IFG time before transmitting (instead of transmitting directly as in the original implementation)

MacCtl: is used to handle time registers on both ONU and OLT. It is also responsible for transmitting to the lower layer at proper time. Currently it seems to work :-) but if you don't want to mess up, try not to touch it... I have spent days in order to achieve the TDMA. IF you see collisions in the Splitter module it means that something went wrong. From release 0.8b, this module is an interface, and a polling-based base class is provided (see bellow on Extending).

Q_mgmt: These modules are responsible for queue management. A simple Round Robin implementation is provided. Bandwidth allocation should be calculated here. This module is extensible and a module interface has been used in the model. So you can replace it with your own module having different functionality.

EPON_Relay: This module implements a switch between the MAC interface and the PON interface. It takes under consideration the LLIDs on the PON network and the VLANs on the Ethernet one. This module is extensible and a module interface has been used in the model. So you can replace it with your own module having different functionality.

EXTENDING

Some features have been added lately in order to make extending the EPON easier. Now both polling-based and non-polling MacCtl modules are included. For polling setups use the ONUMacCtl_P while for non-polling use the ONUMacCtl_NP (see example .ned files).

For implementing new algorithms, for polling create a new module that will extend the OLTQPerLLiDBase_P class. For non-polling you should extend the OLT_QPL_RR class. IN both cases overriding the DoUpstreamDBA method should be sufficient. More complicated algorithms (like Multi-Tread Polling or Two-Stage DBA) will require more changes (more methods need to be overridden)

INSTALLATION

Dependencies

OMNet++ versions 4.0 or 4.1 (http: *omnetpp.org/omnetpp/cat_view/17-downloads/1-omnet-releases/4-older-versions)
INET or INET/MANET FrameWork for the above versions (http: *inet.omnetpp.org/index.php?n=Main.Download)
This version depends on a smaller project for 802.1Q vlans that comes in the same archive.

Installation should be straight forward. OMNet++ 4.0 and INET framework are required. Steps:

Open Omnet++ IDE
Import and compile the INET project
Extract the PON_<version>.tar.gz file
Import Vlans project by selecting the Vlans folder of the extracted archive
- Setup the Project References to point to your INET
- Compile
Import EPON project by selecting the PON folder of the extracted archive
- Setup the Project References to: Vlans and INET
Add the PON project to the project references of your work (optional - if you are building in an external proj./folder)
Now everything should work...

Troubleshooting

Some common errors, I usually receive emails for, are listed bellow:

1. "inetmanet/src/linklayer/contract/Ieee802Ctrl_m.h:83:5: error: expected identifier before numeric constant" There are some illegal characters in the file Ieee802Ctrl.msg and specifically in the "enum EtherType". Solutions:

Fast 'n' Dirty: Delete the enum if you do not need it!
Decent: Open the file (.msg) with a HEX editor and remove the weird characters

2. "Conversion from 'cPar' to 'uint64_t' is ambiguous" Some casting is needed i.e: datarateLimit=(uint64_t)par("datarateLimit");

NOTES

Tested on:

omnetpp-4.1
omnetpp-4.0p1

With many inetmanet versions but...: Latest INET versions will not work (v2). The same for OMNet++ 4.2!. You need to get OMNet++ 4.1 and compatible INET! Porting will not be done (not now at least - Any ported code is more than welcome)

For any comments or corrections email me at bodozoglou@gmail.com

I hope it works for you...
Andreas