OLT
FIGURE 3: Simplified representation of a POL deployment, based on
GPON, which can be used in a building or campus.
52 I ICT TODAY
GPON
2.5 Gb/s
1.2 Gb/s
Central Equipment Room Passive LAN (up to 20 km for a 32 split)
ONT
Central Equipment Room
Add CEx
Add XGS-PON ports
Add/ Replace XGS-PON ONTs
XGS PON 10 Gb/s
GPON 2.5 Gb/s
1.2 Gb/s
10 Gb/s
ONT
OLT CEx
CEx = Coexistence Element (G.989.1)
FIGURE 4: Upgrading the network for new services requiring dedicated
higher bandwidth and speeds.
One of the key benefits of POL
solutions and GPON technologies,
the evolution can happen gradually,
adding additional capabilities only where
the network needs more throughput.
EVOLUTION TO
NEXT-GENERATION
PON TECHNOLOGIES
Here is a simplified representation
of a POL deployment, based on GPON,
which can be used in a building or
campus. The OLT is installed in the
central equipment room and 8 ONTs
are connected via a splitter to a PON
port as shown in Figure 3. GPON
provides 2.5 Gb/s to the
ONTs downstream.
What if new services are introduced
that require dedicated/higher
bandwidth and greater speeds?
A smooth, targeted and cost-efficient
evolution of the network can be
achieved without the need for
a forklift upgrade.
Upgrading the network can be done
in three steps as depicted in Figure 4:
1. Add a co-existence element (CE)
in the central equipment room
to combine GPON with XGS-PON
wavelengths. This is a wavelength
division multiplexer (WM) that can
take multiple wavelengths and put
them on the same optical fiber.
It is defined by ITU standards.
2. Equip the OLT with XGS-PON line
cards and connect the 10G PON
ports to the CE so that 10G PON
symmetrical capabilities are
delivered on the same optical
fiber and splitter.
3. Replace GPON ONTs with 10G
PON ONTs for those services
demanding greater speeds.