What is Access Networks & Its General Architecture?

What is Access Networks & Its General Architecture: Access Networks have historically

been known as the “last mile” bottleneck, meaning that the capacity of the access has been

usually considered the segment that constrained the available bit-rate. For this reason, it

has been foreseen for years that the deployment of a robust access networks would be

inevitable. Fiber is already the dominant medium in metro and long-distance networks.

Today, fiber is also succeeding in the access networks, matching user bandwidth demands

with the cost decrease of available optical devices and technologies.

Ever-increasing user demands for broadband services such as online gaming, high video resolution, smart homes and virtual reality, it is expected that the data rate demand in residential markets will continuously grow over the next decades. Optical access networks are the most future-proof way to widely improve the network performance and effectively meet user’s demands for those broadband services.

Access Network details

Access Network Architecture

GENERAL ARCHITECTURE OF FIXED ACCESS NETWORKS

We have yet only begun the transition into a fully network connected society where everything that will benefit from a network connection, whether it be a person or an object. This connectivity through a wireline network, albeit the most reliable medium, is a challenge.

As part of the telecommunications network, the fixed access network spans the

communication infrastructure from individual users to an aggregation node. The main role of access networks is the connection of the end-users, along with the authentication, authorization and accounting of this connection.

Traditional copper access lines are in the order of 5 Km length in average, depending on the scenario considered (rural, urban). Instead, optical access network architectures rely on the improved features of fiber, and 10-20 Km length can easily be achieved with the current technology. Even longer distances are expected in the future.

The generic term Access Node (AN) is used for convenience to indicate the demarcation point between the Access Network and the Junction Network (Metro Networks). Access Nodes are mostly located in Central Offices (Local Exchanges) but can also be placed in outdoor cabinets. The equipment housed in the Access Node terminates the access lines, aggregates the traffic and forwards it towards the core network.

From the Access Node, connectivity to user’s premises is provided by means of a wired line. To improve the efficiency, rather than running separate lines to each individual user, a Remote Node (RN) with aggregation capabilities, called Fiber Distribution Terminal (FDT), is introduced along the path in the outside plant. The network segment between the Access Node and the FDT is called the Feeder Network.

The network segment between the Remote Node (RN) and the users is usually split into the Distribution Network and the Drop Network. Between both domains, a Dispersion Node called Fiber Access Terminal (FAT) close to the service end-points creates a physical fan out of wires to the users’ premises. Above figure displays the general architecture of an access network.