Vodafone: Use Quality Attenuation to Escape Gig Speed Trap

Vodafone has learned first-hand how quality attenuation techniques and tools reduce capex in fixed-access networks, and the operator is now sharing results of its tests with the broadband ecosystem, hoping operators worldwide will also adopt these mathematically precise solutions.

. Quality attenuation addresses factors often deep in the network, including performance- and cost-effecting issues such as latency, consistency, predictability and reliability. By creating multiple metrics upstream and downstream, the quality attenuation approach reaches beyond typical data rate or packet-layer performance techniques to generate numerical performance data on quality of experience and application outcomes, Gavin Young, head of Vodafone's Fixed Access Centre of Excellence, told Broadband World News. Vodafone now has probes in networks in four countries, measuring and analyzing the fixed-access infrastructures in place.

Data from these probes -- three for upstream, three for down -- give Vodafone invaluable knowledge about the existing network and how potential tweaks will impact performance, latency and so forth, he said.

"We've trialed the technique on different broadband technologies in four different countries and it has given us great insights that a lot of other network measurement approaches and traditional metrics weren't able to do," Young noted. "It even went so far as finding bugs in vendor equipment that the vendor was completely unaware of -- despite having deployed hundreds of thousands of units. It was not in our network, in Vodafone's network, but it was in somebody else's network."

So far, Vodafone has been able to compare vendors' product performance; leverage data from six metrics developed to measure round-trip delay, and analyze the performance of fiber, PON and other crucial technologies, he said. Benefits will increase exponentially as usage expands across the provider's network and, hopefully, the industry, added Young.

One main advantage: This data-driven view deep into the network allows operators to fine-tune performance, changing the conversation from one focused solely on speeds -- and, therefore, price, he said.

"It's perfectly possible to spend a fortune on speed and have customers not notice. The logical extension of [the speed] model is infinite bandwidth which would probably come at infinite cost, whereas with the quality model it's more complex," said Young. "It's not one number. You've got packet loss, latency, consistency, reliability -- all these factors you've got to work out and bring into a quality model. The logical extension of this model -- perfection -- is zero defects, which means zero packet loss, zero packet delay. For engineers, measuring how close you are to zero is a lot easier than measuring how close you are to infinity with the bandwidth model."

Initially drawn by the allure of lowered capex, several service providers are becoming interested in the concept, he said. "As an industry we're all trying to spread our capex," said Young. "The quality attenuation approach gives us the tools to answer questions like, 'Should we move content closer to customers? Should we do queuing or scheduling differently in some areas? What needs to be centralized? What should be distributed?"

The confluence of operators' investments in network functions virtualization, software-defined networks, cloud, plus edge computing and cloudification all combine to make this an ideal time for quality attenuation, he said. Broadband architectures have not changed much over the past decades, but virtualization empowers operators to move around functions and having quality attenuation tools only further enhances this insight, said Young.

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Predictable Network Solutions (PNSol) developed the quality attenuation network measurement, packet scheduling, digital supply chain and distributed systems modeling Vodafone used in its tests and anticipates using in its network. This approach evolved from the worlds of engineering, science and math, and PNSol works with providers from small to large, said Neil Davies, chief scientist and co-founder, in an interview.

PNSol has partnered with Vodafone for about four or five years, Davies and Young agreed.

Typically operators focused on broadband speed, Davies said. But now gigabit is becoming ubiquitous, and operators must compete by other means, he added. "I tend to think of this industry more as a packet-logistics organization as opposed to a communications company. It's more like a global FedEx for packets and logistics companies don't worry that they can't make their planes run faster. What they're trying to do is deliver consistent and predictable services because that's where the value is: If you can deliver a consistent and predictable service, people adjust their business processes, their lifestyles, to fit that predictability. Take away the predictability and they get really annoyed with you because now they don't have any backups," he said. "It's this whole issue of producing something that is reliable out of this whole end-to-end supply chain in which you don't have complete control anymore."

Because of this widespread impact, Broadband Forum selected quality attenuation as an issue warranting further exploration and support. Earlier this year, it debuted "Broadband Quality Experience Delivered," or Broadband QED, led by Vodafone and PNSol. The project will generate a study document that includes an overview of broadband QED, its applicability to broadband networks, theory, measurement technique, use cases and benefits, according to Broadband Forum. In the second stage, the project expects to address specific applicability to the Forum's various Work Areas.

One challenge will be marketing, PNSol Chief Technical Officer Peter Thompson told BBWN.

"Consumers are always prepared to buy more speed because it always made things better before," he said, "and consumers are still prepared to buy more speed because they think it'll get them a better experience -- but it doesn't really. The technology industry as a whole comes from a background of delivering circuits. The only thing you need to know about a circuit is its capacity. Until relatively recently, it was the most important thing but it's not the only thing. Part of the difficulty here is we have to wean people off having an easy to sell, easy to advertise, easy to understand single number which is the thing that shows their product is better than another product. But other industries have done this. There was a time in the car industry when a faster car was a better car. That was it. We've got well past the point where any family saloon sedan you buy is capable of passing the national speed limit. A better car may be one with more seats, or bigger storage area, or a better safety record."

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— Alison Diana, Editor, Broadband World News. Follow us on Twitter or @alisoncdiana.