One of the main tasks of a present telecom access networks - the so-called problem of "last mile" to provide more bandwidth to individual and corporate subscribers at minimum cost.
Modern technology of passive optical networks (GPON (Gigabit Passive Optical Network) has appeared .n the developing telecommunications market. The essence of GPON technology is that a completely passive optical network with topology tree is created between the Central site and remote subscriber nodes. Passive optical splitters (a compact device that does not require power supply and maintenance) is located in intermediate nodes of the tree. Distribution network access GPON based on tree-type fiber cable architecture with passive optical splitters on the nodes may be most cost-effective and capable of providing broadband transmission of applications. The architecture GPON obtains the necessary effectiveness of capacity and nodes in the network, and bandwidth, depending on the current and future needs of subscribers.
Architecture advantages GPON:
the lack of active intermediate nodes
the economy of optical transceivers in a Central node
the economy of fibers
the ease of connection of new subscribers, and serviceability (connection, disconnection or malfunction of one or more subscriber nodes does not affect the work of others)
A tree-type topology P2MP allows to optimize the placement of optical splitters based on the actual location of subscribers, the cost of OK laying and operation of cable networks.
The disadvantage is the increased complexity of PON technology and lack of redundancy in the simplest topology tree.
The main idea of the architecture of GPON is using just one transceiver module in OLT to transfer information to a variety of ONT subscriber devices and receive information from them.
High speed data transfer, which is 2488 Mbps to the subscriber and 622, 1244 or 2488 Mbit/s from the subscriber (depending on the specific device model) allows to qualitatively expand the band Internet access for each subscriber. The optical seals allow operators to increase the bandwidth and to add and remove devices without changing the existing network infrastructure. The physical GPON PMD level provides two classes interfaces: class 1 for distances up to 10 km and class 2 for 20 km by the branching ratios of 1:32 and 1:16.
The use of passive optical networks provides the operator with the immunity of communication channels, and the use of all popular protocols and communication technologies IGMP, DHCP, STP,TCP/IP, and so on. In the absence of intermediate active elements, managing subscribers ' devices and updating their software is centralized and automated, thus keeping the investment in new equipment.
Modern GPON devices OLT communicators and ONT client devices became functional. Different dimensions and density of ports allow operators to choose the solutions that will help them to strike a balance between the number of connected subscribers and costs.
At the moment the zone of deployment of broadband access network using GPON technology in the area of ATS-254/255 Huawei manufacturer of MA5600T communicator and in the area of ATS-265/266 ZTE manufacturer of C-300communicator. Device ONT provide access to Internet resources in the usual way, but with higher speed and lower costs from the operator.