Case Study: Occam Networks

Occam pushes broadband boundaries with UNH-IOL DSL interop testing

The Challenge: Optimize IP video delivery through DSL chipset interop testing

Occam Networks sells telco access equipment that helps carriers overcome the challenges of delivering converged voice, data and video over broadband Internet pipes. Occam is successfully enabling commercial deployment of IP video over DSL in part because of its commitment to maintaining or improving system-wide performance with every new software release. Yet Occam’s leading-edge engineering pushes the very limits of today’s fastest DSL technologies.

Despite its rapid adoption, the newest and most powerful DSL transport technologies, ADSL2/2+, are still far from mature; every new firmware release from either a central office (CO) or customer premises equipment (CPE) chipset vendor will fix outstanding issues but has the potential to introduce new ones.

As Occam well knows, high-quality IP video demands DSL performance orders of magnitude above traditional DSL networks. It is thus critical for Occam to thoroughly regression-test every new CO chipset firmware release against the major CPE chipsets. This also means testing all possible firmware permutations in both recently released and currently deployed vendor equipment. This kind of testing must go far beyond typical rate/reach testing, digging into the innards of protocol behavior for communication between the Broadband Loop Carrier (BLC) and CPE, error protection, seamless adaptation in the presence of dynamic noise environments and a number of other aspects of DSL technology not commonly paid much attention in typical data-only deployments.

Occam has a number of commercial deployments of IP video. Through close partnership with these customers as they turn up IP Video over ADSL1/2/2+, Occam knew that DSL performance could be improved with the proper fine-tuning. What it needed was a controlled, vendor-neutral environment to hash out the issues between CO and CPE chipset and firmware vendor implementations.

The Solution: Leverage UNH-IOL test bed to tackle large-scale CPE and CO interop testing

Occam turned to the University of New Hampshire InterOperability Laboratory (UNH-IOL) to test its Broadband Loop Carrier (BLC) 6208 and BLC 6212, an IP/Ethernet Loop Carrier implementing the ATU-C (DSLAM) component of the xDSL specifications for ADSL1/2/2+.

“UNH-IOL has the ideal mix of infrastructure, services and well-trained professionals necessary for Occam to compliment in-house regression testing with a breadth of test suites,” said Dov Zimring, Occam Networks Triple Play Architect. “Given the number of different tests that must be performed, the number of CPE they must be performed against, and the number of firmware permutations for each CPE, the reporting and analysis of test results is crucial to the final outcome.”

Testing involved a breadth of the DSL Testing Services conformance and interoperability test suites executed against a cross section of the industry’s best-of-breed CPE vendors as well as participation in industry group tests. “The DSL Testing Services staff have been extremely flexible and innovative in reporting and helping to analyze the results of the many tests we run,” Zimring said.

In addition to supporting Occam’s requirement of only releasing software that will maintain or improve DSL field performance, tests performed at the UNH-IOL were instrumental in Occam’s endeavor to establish best practices for the deployment of IP video over ADSL2+. Occam has since published a white paper, “ADSL2+ Best Practices for IP Video Deployments” to its customer base and is in the process of disseminating these best practices to the industry for broader adoption. Using these best practices, Occam has repeatedly outperformed competitors in IP Video trials.

“IP Video is the ultimate lie detector test for ADSL2+ interoperability,” Zimring said. “Occam's ability to discover interoperability issues between vendors and firmware revisions enables us to proactively work the chipset vendor community for fixes, inform our customers of any potential pitfalls, and optimize the technology around the kinks.”

The Results: Occam slashes R&D time and costs, is early to market with advanced ADSL2/2+ support

The UNH-IOL DSL Testing Group was instrumental in helping Occam to become one of the first vendors on the market to support new ADSL2/2+ features including Annex L for extended reach, Annex M for business applications and pair bonding. “UNH-IOL’s staff is incredibly knowledgeable about the standards and encompassing technology,” Zimring said. “They have been very supportive in creating new test suites to help us to ensure that our customers will purchase optimal performance, scalability and reliability when they purchase the Occam Broadband Loop Carrier.”

Occam's decision to aggressively leverage the UNH-IOL to compliment in-house testing has produced results that would have otherwise required many extra months on a per-release basis or a massive investment in additional headcount. Occam's engineering and QA teams will continue to leverage the UNH-IOL DSL Testing Services for each new firmware release by its CO chipset vendor or any one of the CPE chipsets the company works with.

“Thanks to Occam's commitment to quality and involvement with the UNH-IOL, we have been able to protect our customers from issues that would not be discovered with the minimal rate/reach interoperability testing many access vendors perform,” Zimring said. “The net benefit to our customer base is a far more reliable product, from one upgrade to the next.”