ZyXEL Communications PLA-470 V2 - V3.0.5 Przewodnik Instalacji Pobierz pdf (Strona 50)

CHAPTER 3

Functionality

The functionalities of the PLC networks are introduced in this chapter. The technol-

ogies used in these networks are simple enough to be integrated into a single chip so

that components can be manufactured at a very low cost. They will still be relevant

up to the introduction of new PLC interfaces making it possible to increase the

throughput of the devices.

The PLC functionalities take advantage of the many technological develop-

ments of fixed networks, in particular ADSL, Wi-Fi, Ethernet, and so forth. The

PLC electrical component makes it necessary to employ technologies used to make

the PLC link, which is the main weak point of this type of network, reliable.

The main functionalities of the PLC are the following:

•

network mode, which is used to manage the network organization and com-

munications between the various PLC devices;

•

PLC frame management mode, in particular fragmentation and reassembly,

which are used to solve the huge data volume transmission problem;

•

medium access technique, which includes the synchronization of the network

devices and priority management;

•

quality of service, which authorizes the transmission of voice or video data in

PLC environments.

Network Mode Functionality

One of the major functionalities of the PLC networks is the network mode, which is

used to manage all PLC devices from the same network.

Since, by definition, a network consists of several devices exchanging data, it is

necessary to implement an exchange management system so that they are organized

and optimized.

There are several network organization methods. The various PLC technologies

use one of the following three network modes:

•

Master-slave mode. Can be compared to a client-server type IP network in

which a master device manages the exchanges between the PLC devices of the

network. The slaves can exchange data between themselves according to mas-

ter management.

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ZyXEL Communications PLA-470 V2 - V3.0.5 Przewodnik Instalacji Strona 50