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Triple play broadband services: Quality assurance testing

Network operators are increasing triple play services to capitalize on their broadband infrastructure. Testing can play a significant role in ensuring that service quality is high, not only for new triple play customers but for the customer base at large.

Triple play services usually mean voice, data, and video bundled over a broadband connection. These networks represent the ongoing goal of network operators to gain maximum revenue leverage for their investment in infrastructure, and so protecting that investment is critical. Testing can play a significant role in ensuring that service quality is high, not only for new triple play customers but for the customer base at large.

The "new" and "base" customer distinction is important here because quality assurance testing for triple play should be considered in both these lights. New customer testing is focused on access qualification and initial setup validation, and thus tends to be customer-focused. Quality assurance testing associated with baseline operations for the customer community at large is focused on validation of the capacity and performance plan for the community.

Testing quality for new broadband customers
With the increased focus on sustaining broadband margins in the face of pricing pressure at the retail level, nearly all network operators have gone to self-installation of broadband, meaning that the customer is expected to install the broadband modem. This has focused access qualification on a combination of "single ended loop testing" or SELT as a pre-qualification strategy, and on interactive testing with the modem as an install-time qualification process (sometimes called "dual end loop testing" or DELT).

SELT is a key step for most operators since it predicts loop quality before the customer has committed to a service, and thus prevents a negative install experience and the resulting customer service call. However, SELT is obviously less predictive of the full set of loop problems, and operators may need to adapt their SELT plans to the conditions in their market area.

Cable MSOs will generally have a good idea of the quality of the cable access connection from the experience of nearby users on the same span, and so the process of single-ended testing is less likely to be employed or even incrementally useful. For cable operators, the best strategy is normally to wait until installation and then use DELT mechanisms of cable modem diagnostics to qualify the connection. If the cable span is providing good customer support in general, problems with the install are likely to involve the customer feed or in-home wiring, and this may require a technician to diagnose and resolve.

With DSL services, SELT capability may be built into the equipment or provided by an external test system. Where the DSL chipset provides loop testing capability and where these capabilities seem predictive, operators may simply "light" the digital spectrum on all loops. This is particularly likely to be the approach where DSL service is offered from a remote terminal, since sending craft personnel to connect DSL cards one by one as customers subscribe is not likely to be an economical strategy. External systems for loop testing are more likely to be used in a central office with "home-run" copper because the concentration of loops justifies the decision.

Preemptive DSL SELT loop qualification by any means has to be measured against the yardstick of broadband adoption. Where adoption rates are high, proactive testing and "lighting" the digital spectrum on the loop in anticipation of service is almost certain to pay dividends in weeding out problems before they impact customers. Most operators will test a group of loops and then resolve any problems with a single truck roll to reduce per-loop commissioning costs.

With any kind of broadband, the DELT process will continue as the customer is in service, providing statistics on the performance of the broadband connection and allowing operators to perform trend analysis if desired. The number of broadband customers makes automating this analysis critical, and some operators will use threshold alerts to trigger a historical review of broadband access performance rather than running trending analysis on all connections all of the time. A useful strategy is to perform correlation on access based on common component hierarchy, so that the chance of picking up common faults is greater.

Assuring quality for the general customer base
Beyond the physical media to the customer, broadband triple play networks can suffer problems deeper into the infrastructure. Most of the inside and outside plant equipment used in triple play networks has its own test and maintenance processes that include ongoing network monitoring and management. These will normally identify degrading performance in any common facility, and will thus permit operators to schedule maintenance to reduce cost and maximize customer satisfaction. It is a good practice to do a more intense analysis of any network component set when maintenance must be performed on another device in the same area to optimize the use of craft resources.

The most significant problems likely to impact triple-play quality other than initial access connection problems are problems related to congestion. Triple play networks are particularly susceptible to congestion because they carry traffic that must be prioritized to reduce latency and loss of packets, particularly for video. This is where the concept of a capacity and performance plan comes in; during network design operators should record the conditions under which the network was designed to operate and then monitor to determine if there are trends that threaten to compromise one or more of the requirements. Any signs of a negative trend should be managed quickly to insure that services are not lost.

A special issue in triple play is the question of customer access to customer care facilities. If a customer has complete communications dependence on their triple play service set, loss of their facilities also cuts them off from customer care. This means that it is critical to spot these problems from the network side and deal with them quickly, since customer demands will escalate the longer they are unable to report the problem.

This also means that those components of the triple play network that will, if they experience a problem, impact all services should be monitored with special care. Customers who also have mobile service with the operator should be advised to use their mobile phone to report problems; experience shows that customers who have a chance to report a problem immediately are three to four times as likely to be satisfied with the outcome of their support experience than those who cannot.

About the author: Tom Nolle is president of CIMI Corporation, a strategic consulting firm specializing in telecommunications and data communications since 1982. He is a member of the IEEE, ACM and the IPsphere Forum, and the publisher of Netwatcher, a journal in advanced telecommunications strategy issues. Tom is actively involved in LAN, MAN and WAN issues for both enterprises and service providers and also provides technical consultation to equipment vendors on standards, markets and emerging technologies.

This was last published in July 2007

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