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The Impact of ADSL Interoperability
Testing on the DSL Market
Service Providers want ADSL modems that meet a standard set of interoperability
tests and achieve a guaranteed level of service.
DSL Forum is producing an ADSL interoperability test specification,
known as WT-062*, which is supported by all key NEM's, Service Providers,
access IC manufacturers and Independent Test Labs. Success in selling
DSLAMs and modems to Service Providers is quickly becoming a simple
matter of proving you can pass DSL Forum's WT-062 interoperability
tests. This is a new testing hurdle that suppliers need to conform
to before they can sell their equipment.
- Modems that
pass DSL Forum Interoperability testing will be desired
by Service Providers
- With DSL Forum
certified modems, Service Providers will be able to offer
QoS based DSL
- Independent
Test Labs are being certified by DSL Forum as the official
test houses to provide modem certification
- The Spirent
WT-062 test system is the only solution that provides the
accuracy and performance to ensure correct testing results
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Spirent WT-062 Interoperability Testing
Solution
To ensure that DSLAMs and modems meet a minimum
set of specifications when used together, ADSL Service Providers,
Network Equipment Manufacturers and Independent Test Labs have come
together at DSL Forum to produce the WT-062 ADSL Interoperability
Test Plan. Issues of control, consistency, repeatability, as well
as automation, should be a concern to every WT-062 user. Spirent
offers a solution that combines DLS physical layer with SmartBits™
traffic generation and analysis tools.
Physical Network Simulation
Wireline
A small variation in bit rate can mean a difference between passing
or failing WT-062. Issues of noise floor, accuracy and repeatability
are key technical issues that must be considered. In response to
this, Spirent has developed a software-based compensation package,
which is integrated with the DLS 400IA, to meet the accuracy, repeatability
and requirements specific to WT-062.Customers who have a DLS 400A/N/HN
can upgrade to the DLS 400IA system, which includes the additional
testloops and software compensation package.
Noise
Real world noise has a dramatic impact on the
performance of ADSL modems and DSLAMS. WT-062 has captured many
of the worst case scenarios and specified a set of crosstalk, RFI,
impulse and white noise test requirements. In response to these
requirements, Spirent is developing the DLS 5200IA WT-062 Noise
Impairment System. The DLS 5200IA, available in the summer of 2002,
will provide all impairments specified in WT-062 including RFI and
common mode noise injection. Other features include automation via
Ethernet control, high accuracy and test repeatability, as well
as ETSI / ANSI compliant crest factor.
For immediate test needs, the use of two DLS 5A01H Noise Impairment
Generators, together with the DLS 5A17 WT-062 Noise Impairments
CD-ROM, will allow for most WT-062 tests to be performed.
Traffic Generation and
Analysis
Using the unique capabilities of the 10/100 Ethernet
and ATM SmartCards, SmartBits™ allows for unparalleled end-to-end
stability, frame loss, and latency measurements up to full wire
rate.
Testing Automation with Spirent ScriptCenter
With approximately 1000 tests required in WT-062
for each test cycle, the ability to automate saves time and money.
Spirent offers ScriptCenter , a GUI-driven automation tool, for
this purpose. When paired with the DLS 1200 ScriptCenter Library,
the physical network simulation equipment and the traffic generator/analyzer
can be combined by the user into a fully automated solution.
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