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.
