ISPs Can’t Build Way Out of Network Congestion, FCC Told

Academics and industry officials said it’s unrealistic to believe ISPs can build their way out of congestion. Internet traffic will increase six-fold from 2007 to 2012, and 10 percent of users account for more than 60 percent of the traffic, said Paul Sanchirico, Cisco engineering vice president. ISPs would need to at least double capacity now if they stopped using net management tools, he said. “Throwing capital at this problem is frankly … not attractive for most businesses like mine,” said Bill Smith, AT&T president of local network services.

Management probably will always be needed, but it must be done intelligently, said Scott Jordan, a professor at the University of California, Irvine. He called service quality and traffic degradation “two sides of the same coin.” Congestion tends to be “bursty,” happening sporadically and usually for only a few seconds, Jordan said. The most intelligent way that providers deal with congestion is quality of service, under which different kinds of packets get different priority, he said. Either the ISP prioritizes types of traffic, as the U.S. Postal Service does with Priority Mail, or the company reserves specific amounts of bandwidth for different priority levels, he said.

No management technique is reasonable or unreasonable in the abstract, Jordan said: What matters is how an ISP uses a tool. Providers may assign priority based on the type of application -- if the application is an ISP managed service - - payment by a company or customer, or the traffic’s source or destination. Currently, each ISP has its own quality of service policy, so traffic might be prioritized differently on networks that send and receive it, he said.

More openness and information about network management practices is needed, Claffy said. AT&T, for example, insists that management is critical but has offered little supporting data, she said. Rather than put out a broad data request, the FCC should make ISPs explain and defend their network management procedures, she said. A blanket request would place the FCC in a “losing fight” in which it would have to prescribe the best way to do management, she said.

“I can’t sell a router without QoS capability,” said Cisco’s Sanchirico. ISPs get at least twice the bandwidth with QoS tools in place, he said. “The customers’ expectations are really driving the need for network management,” Sanchirico said. Management helps ISPs protect customers against service disruptions and degradations, as well as spam, viruses and other cyberattacks, he said. Meanwhile, deep-packet inspection is “nothing more than providing a more granular view of traffic data,” he said. Tools are used by ISPs to understand the type but not the content of traffic, Sanchirico said. An ISP might use inspection to find out which subscribers are infected with a virus, he said.

Network management allows AT&T to provide converged services, Smith said. “We couldn’t be in the video business … if we didn’t have the ability to do this.” Most consumers don’t understand all the technical issues behind net management, he said. They just want the service they're paying for to work, he said. Smith set out four business “principles” that AT&T follows in managing its network. The company strives to use all possible resources, and keep available resources filled with traffic that have a high probability of being delivered successfully, he said. In case of overload, it gives priority to routes that make “most efficient use” of network resources, he said. And the company tries to hold down traffic congestion and stop it from spreading, he said.

Cable companies must manage network spectrum to meet consumer demands or customers will leave for competitors, said CableLabs President Paul Liao. Cable companies carefully watch how the network is being utilized, he said. Well before congestion hits, cable companies start preparing networks through a variety of spectrum management methods, including splitting nodes, adding more channels and going to higher modulations, he said. Beyond spectrum limitations, cable networks look like other broadband networks, he said.

Flexibility to handle congestion with network management is particularly critical in wireless networks, said Tom Sawanobori, Verizon vice president of network and technology strategy. Wireless is more complex to engineer and manage for various reasons, including radio signal fading and interference, he said. Its users don’t stay in one place. And spectrum is a limited resource, and provides a fraction of the bandwidth wireline and cable networks offer, Sawanobori said.

Jonathan Rosenberg of Skype detailed the VoIP provider’s network management approach. Video consumption has been rising, causing capacity issues, he said. The key is to be adaptive to the constraints of the network, computer and needs of the user to minimize the consumption of resources while giving the user the best experience, said Rosenberg, Skype’s new chief technology strategist. Skype manages bandwidth jointly across all media streams, including audio, video and transfer, he said. Calling Skype’s usage of network resources conservative, Rosenberg said the company adapts based on network feedback. The approach throttles down the transmission rate based on available network resources, he said. Meanwhile, usage of media relays worsens the user experience, he said. As a result, Skype algorithms are tuned to minimized media relay usage only to cases where the network prevents direct connections and the company attempts to use nearby relays in order to reduce delay and minimize network resource consumption, he said. The company also puts hard limits on audio and video bandwidth when relays are used, he said. Skype is an application provider not a telecom service provider, Rosenberg said in response to a question about whether Skype should be subject to carrier obligations.

Tuesday’s workshop was the start of the technical advisory process at the FCC, Office of Engineering & Technology Chief Julius Knapp said, opening it. The goal of the event was to “lay the foundation” and get a basic understanding of how networks operate, he said. The agency also will hold ex-parte meetings with engineers and others interested, he said. The FCC has three more workshops planned for this month and January.