DirectLight
products continue to demonstrate strong value for
its customers in network emulation and test. When
a leading ILEC needed to develop a capability for
more effectively testing its video distribution
network for its FTTH roll-out, it chose the DirectLight
IG optical switch. DirectLight is installed in the
service providers network testbed for its next generation
video distribution system, and is used as part of
a capability to reconfigure numerous network elements
while testing network performance and link budgets.
The
DirectLight switch is part of an end-to-end video
transport & distribution network, from head-end
office to serving & distribution office, and
into the PON network. Rather than statically connecting
all network elements together, the testbed uses
the switch at all intermediate connection points
for both active elements and PON elements. This
enables a user to reconfigure the entire network
topology using software within a matter of seconds.
Changes can now be made rapidly, without any manual
patching, and include:
- Adding/subtracting
EDFA amplifiers (number of amplified spans)
- Adding/subtracting
fiber spools to add PON span
- Inserting
one or multiple splitters with 1:8, 1:16, and
1:32 split ratios
- Inserting
test equipment at any point in network (both optical-layer
and service-layer testing)
- Adding/subtracting
a number of ONTs, ONUs for system loading
Typical
evaluation and qualification can involve 50-100
different network topologies, each of which can
take 2-3 hours to set-up. With a DirectLight switch
making all connections, this can be reduced to minutes.
DirectLight
is able to handle all upstream and downstream wavelengths
(including 1310, 1490, and 1550), allowing testing
across the video, and voice/broadband networks.
Since link margin is so critical, it is absolutely
necessary to minimize optical impairments in the
testbed. For Continuum’s customer, having low
insertion loss (1.3 dB typ) and high return loss
(>55 dB typ), minimized the impact on the resulting
measurements. High repeatability (+/-0.05 dB typ)
was important to ensure a consistent link baseline
between configurations.
In
addition to vastly reducing set-up time, Continuum’s
customer is relying on DirectLight to offer other
advantages:
- Provide
the ability to script for 24/7 test automation
- Share
& control testbed resources from several geographical
locations
- Create
a highly trusted baseline link, by eliminating
variances from manual connection or dirt/damage
to fiber connectors
- Using
the built-in power meter to quickly identify/troubleshoot
power levels anywhere in the network
- Using
the built-in optical attenuator to test link margins
and equipment alarming capabilities
Other
areas where DirectLight can be used for FTTH-related
lab testing include testing provisioning software,
interoperability between vendor ONT/OLT equipment,
and network installation & maintenance procedures.
