The technological objective of this project is the development of a methodology for modeling and simulation of communications networks and next-generation heterogeneous systems, with the aim of studying their performance, interoperability, discovering the problems that can occur in the real world in terms of engineering of traffic, routing, quality of service, etc.

The motivation for this project is the use of simulation as a means of tool for the development and investigation of architectures and new generation protocols within the scope of IP networks In In particular, it has been chosen as a first scenario for its modeling and simulation of the access network known as “Ethernet in the last mile, Ethernet first mile (EFM)…

The purpose of this project is to obtain, analyze and make available the models developed and the results of the project are made available to interested companies. results obtained on a real EFM-based architecture.

The most important motivations and advantages of Ethernet development in metropolitan networks are:

  • The great “boom” that has emerged in the last few years in Ethernet technology.
  • Reductions of transformations in the link layer, therefore reduction of delay, jitter, etc., a data infrastructure and a global standard that ensures interoperability.
  • Cost reduction in the transformation hardware.
  • Simplicity of management, point-to-point Ethernet.
  • Exploitation of the current deployment of cable networks (twisted pair).
  • High capacity for broadband services.


Operators’ interest in this technology is focused on the existing cabling deployment (dual-pair, double-pair, double-pair). and fiber optics to offer the highest quality of service. possible at lower cost and to offer broadband services

EFM’s technical specifications are set out in an EFM standard. IEEE (Institute of Electrical and Electronics Engineers) organization, more specifically in the IEEE 802.3ah standard. This standard is, in the currently in the process of standardization and will allow after its The finalization of a multitude of manufacturers that implement it will be completed.

One of the outcomes of the project is the construction of the network elements making up the EPON architecture: OLT, ONU and Splitter and the implementation of the link layers of these three optical passive and network components.

Algorithms have been developed to improve the performance of these access networks for use in services with high network requirements.


The network architecture that has been developed is point-to-multipoint. over optical fiber: EFM PON (Passive Optical Network) or EPON.

The components of the EPON access network are:

  • OLT (Optical Line Terminal) : network headend of the EPON architecture, it works as an access node, connecting the network to the optical access to the backbone.
  • ONU (Optical Network Unit): it is the component The network that is located at the end-user’s location. Your main function is the TDMA access to the medium (multiplexing in the time) by concentrating end-user traffic.
  • Passive optical splitter: passive optical multiplexer.
    • In the downstream direction towards the UN, it forwards the frames arriving at the incoming port through all the outgoing ports.
    • In the upstream direction it collects and unifies all UNO traffic in the link with the OLT.
  • Clients: Terminals, servers or Ethernet LANs.
  • 1 Gbps single-mode fiber optic links.


The core of the project corresponds to the definition and implementation of the in the OPNET Modeler simulation tool of choice for the various components of the EPON network.

This tool allows to design and simulate the operation of networks. communications, with the objective of obtaining a series of statistics to determine whether the network is functioning correctly and the existence of of unwanted phenomena.

From the OPNET simulations, it is possible to determine the feasibility or not of a certain network configuration. A very important advantage of is the possibility it offers to innovate in the creation of new products and services. of a new communications network element.

OPNET allows for the inclusion of new protocols in the components thanks to its internal structure. Each The network component is modeled as a set of nodes that are correspond to protocols belonging to the present OSI levels on the device. At the same time, each node has underneath it a machine of finite states that implements its functionality, by means of C code, being the lowest level of the tool.

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