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Passive probe improves optical network monitoring, TDM to IP glitches

Wholesale VoIP services proved to be a boon for one operator, but troubleshooting TDM to IP glitches threatened success. Replacing manual diagnostics with a passive test probe paid off with improved optical network monitoring and faster resolution times.

Rolling out wholesale voice over IP (VoIP) services for competitive local exchange carriers (CLECs) in the Western United States proved to be a revenue boon for one service provider, but troubleshooting time-division multiplexing (TDM) to IP translation hiccups remained a challenge. Replacing manual diagnostics with a passive test probe has cut mean time to repair (MTTR) in half and improved optical network monitoring.

"The problem we were trying to solve was one of integrated capture of a call in process that crosses the lines of TDM and IP [Internet Protocol]," said Brady Adams, CTO of 360networks, a Seattle-based operator of wholesale VoIP and fiber optic network services. "When you're talking TDM to IP, there are different attributes you're looking at for call quality, and during that translation, it can be very difficult to [determine] what [affected] the performance of this call."

When 360networks launched its wholesale VoIP service three years ago across its 20,000-mile fiber-optic network, it sold the service as an easier way for CLECs with older infrastructure to ride the next-generation network train, Adams said. The service caught the eye of very large enterprise customers as well, and the wholesale VoIP service became a "substantial" part of 360's revenue, he said.

I don't think it uncovered anything we didn't know about in our network. I think it allowed us to uncover [problems]quicker.
Brady AdamsCTO, 360networks

But then the problems popped up. All-IP calls did fine, Adams said, but TDM to IP translations often resulted in poor call quality, dropped calls or one-way audio.

It was an optical network monitoring and management nightmare. The tools that technicians and operational support staff had been using still required them to manually capture and analyze call data, Adams said. From diagnosis to resolution, the process took two hours for an average help-desk ticket tracking 10 individual calls.

"It was very manual and it was very time-intensive," he said. "There are a number of platforms out there, but none of them to date have had the ability to integrate both the TDM and the IP side of the call into a process in a very simple fashion -- something that is very easy to train our NOC [network operations center] personnel and even our customer base to some extent [to do]."

Easier optical network monitoring with passive test probe

Looking for a more advanced, integrated troubleshooting and testing tool for optical network management, Adams turned to Empirix -- a vendor he had worked with years ago as vice president of engineering at Grande Communications, a Texas voice and broadband service provider.

Empirix's Hammer XMS, a passive traffic network monitoring probe, sits like a net in a rushing river to capture and record call data as it traverses the network, allowing for real-time proactive optical network monitoring, according to Dan Teichman, senior product marketing manager at Empirix.

"Like many service providers, [360networks has] made an investment in an IP infrastructure to provide voice over IP, but they still have TDM or old circuit switch technology that they interconnect to other carriers with," Teichman said. "They can get visibility as it enters and exits their network, as well as what's happening within their own network. It's a very common [need]."

The graphical user interface that comes with the Hammer XMS probe is easier than other software products for engineers, support staff and even CLEC customers to understand and analyze, Adams said. The software, which presents the analysis as a ladder diagram of call flow data, also does the data and analysis collection for them. The result: An average ticket of 10 calls takes 30 minutes to resolve.

The tool hasn't revealed any major faults in the network but rather a faster way to diagnose frequent but minor glitches in TDM to IP conversions, or vice versa, Adams said. Technicians use the probe mostly near 360network's core routers and at various locations within the network.

"I don't think it uncovered anything we didn't know about in our network. I think it allowed us to uncover them quicker," he said. "Empirix puts it together in a format that allows you to save time.... It allows us to get information more promptly. If there are changes in our network, we can analyze those much more quickly."

Using an intuitive interface has made optical network monitoring and management issues "very easy to share with a customer or share internally to look at the faults in the network," Adams said.

"There's an educational piece that goes on internally … and it's something that's very enlightening to our customer base," he said. "The [troubleshooting response] time saving is a great thing, but it's also [as important to be] able to prove to the customer with confidence that you have the tools and ability to respond to their demands in a timely manner."

Let us know what you think about the story; email: Jessica Scarpati, News Writer

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