FTTH Business Guide - AWT.be

Network design
An FTTH network is a long-term investment. The anticipated lifetime of the cable
in the ground is at least 25 years – that’s the manufacturer’s guaranteed minimum
lifetime; the working lifetime is likely to be much longer. The active equipment
will be upgraded in this timeframe, but it should be possible to reuse the
infrastructure. With this in mind, it is worth considering a design for the cable
plant that is capable of supporting different network architectures.
In terms of the cable plant, there are two main options for the topology of the
access network: point-to-point and point-to-multipoint.
Point-to-point network
Point-to-multipoint network
Installation inside an MDU
In a point-to-point (P2P) topology each
end-user is served by a single fibre that
runs all the way from the central office to
the customer’s home or office. This will
probably consist of several sections of
fibre joined with splices or connectors,
but there is a single, uninterrupted
optical path from the central office to the
customer premises. This is sometimes
referred to as a “home run” network.
In a point-to-multipoint topology all
traffic is carried on a single, shared fibre
from the central office to a branching
point, and from there the traffic is routed
onto individual, dedicated fibres, one per
customer. In a passive optical network
(PON) routing is accomplished optically
using passive optical splitters. Splitters
can be centralized or cascaded (not
usually more than two).
The customer premises in either case
may be a single residence, or a multiple
dwelling unit (MDU) in which case active
equipment may be installed in the
building in order to aggregate traffic
from all customers in the building on
onto the single fibre.
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