Bottleneck blues - Internet - Internet/Web/Online Service Information

Figuring out what's slowing the Internet down is the first step to developing corrective measures.

It was a shock to many of us to read about the travails of America Online (AOL). Millions of users of the Internet realized suddenly that Internet service providers (ISPs) were experiencing significant growing pains that required a substantial investment to alleviate. A year later, it had become apparent that the problem did not lie only with the ISPs--it was a growing issue for the local exchange carriers (LECs) as well.

In its interim report to the Federal Communications Commission, the Network Reliability Steering Committee (NRSC) found that excessive Internet usage was leading to significant slowdowns in parts of the public switched telephone network (PSTN). "The principal point of congestion is at the ISP's local switch," notes Bell Atlantic's Ray Albers, who chairs the NRSC. "There have been reports of delayed dial tone and all circuits busy."

There is little doubt that the legacy telephone network is being stressed by a rapidly escalating number of Internet calls. The LECs spend millions of dollars a day on upgrades that bring them not a penny of extra revenue. This, in a nutshell, is the dilemma faced by U.S. telcos as they struggle to accommodate the ISPs and their subscribers.

"Long holding times tie up both switch resources and interoffice trunks and small increases in Internet traffic can increase the probability of call blocking," say Bellcore consultants A. H. Atai and J. J. Gordon.

Alan Pearce, who served as chief economist at the FCC at the time of divestiture, believes that the regional Bells should do more. "There are some people who say that congestion is a direct result of unbundling the local loop," he says. "They claim that this is potentially dangerous because it affects network reliability. The Commission's response to this was to tell the incumbent local exchange carriers (ILECs) to set up a proper organization to study the issue. I think that later this year we'll have some pricing and technical clarity."

The problem is not one of complete network failure, says Albers. Rather, it involves a creeping paralysis in certain portions of the network due to Internet traffic. Over the next few years, the PSTN will provide more and more residential users with access to the Internet and other data networks. Both network providers and equipment vendors are seeking ways of off-loading Internet traffic from the PSTN onto data networks.

Today's network economics encourage Internet users to stay online twice as long (on average) as with metered rate plans, say Atai and Gordon. "Understandably, given the number of online users, this doubling of call duration can result in significantly higher loads for the PSTN. Internet growth forecasts from several sources predict that in two years, 30% of U.S. households will be online compared with 15% in 1997."

This is what troubles the LECs, says Albers. Bell Atlantic filed a study with the FCC based on 10 telephone exchanges with ISP connections in the Washington, D.C., area. In one case, all Internet traffic from the District of Columbia, Northern Virginia, and Maryland was homing in on one exchange used by AOL in Hernden, Va. The LEC could not keep up with traffic surges, leading to subscriber complaints of slow dial tone and busy trunks.

APPROACHES

Atai and Gordon take a technical approach to the problem. The solutions most popular with the telcos lead to architectures that off-load Internet traffic and treat it differently from voice calls. This strategy involves Internet call administration, authorization, and authentification (AAA) procedures that are unpopular with the ISPs, as they claim it reduces their ability to manage their businesses.

Most off-load architectures move modem functionality away from the ISP and closer to end users, so that Internet calls can be converted to packet format as early as possible. This lets the telco take advantage of gains achieved through multiplexing Internet connections. But to do this without alienating the ISPs, the LECs must address their concerns regarding access to, and security of, ISP customer information.

"ISPs are extremely sensitive about relinquishing the administration of modems (or modem functionality) to third parties such as the LECs," note Atai and Gordon. "Retaining control of modems allows them to directly manage their own customer bases without having third parties intrude on this relationship. Sensitivities regarding customer access are heightened by the fact that some LECs have ISP subsidiaries."

OFF-LOADING

There is little disagreement that data circuits are a more efficient means of carrying Internet traffic than the PSTN. Thus it seems obvious that this traffic should be taken off the PSTN as quickly as possible. The contentious issue that faces both the LECs and the ISPs is how and where this should be done without disrupting current services.

The first approach involves the interception of Internet calls and their redirection to a packet network on the subscriber side of the local exchange. In this way all PSTN elements including the originating switch, trunks, and the egress switch are bypassed. The local switch still has responsibility for some call-related signaling.

The other alternative is to allow Internet calls to pass through the exchange before being redirected for delivery to the ISP over a packet network that bypasses the PSTN trunks and terminating switches. The originating switch is still involved in both the signaling and transport phases.

The effectiveness of either or both approaches depends on the usage patterns of Internet users and on how the costs are attributed throughout the PSTN. Here are the pros and cons:

1. Pre-exchange: switch costs are reduced and heavy users are identified and targeted for special processing. Additional network support systems that manage pre-switch off-loading lead to increased costs. Because these systems will be located at the edge of the network, this could cause stranded investments for LECs.

2. Post-exchange: there is no need to identify heavy users and economies of scale are achieved by sharing equipment among many users. All Internet calls and signaling can be routed through a hub facility using the intelligent network (IN). The main disadvantage is that local switch costs due to excess Internet traffic are not reduced.

USING THE IN

"There is a characteristic of the IN that can be employed to provide more powerful and efficient information services, including the alleviation of congestion by heavy Internet usage over the PSTN," says Don Berteau, president of The Netanya Group, based in Sebastian, Fla. "The optimal approach involves the incorporation of computer databases into the signaling network for network control functions."

Berteau says the best solution is to incorporate a network management computer that communicates with the SS7 service control point (SCP) over a packet link. This computer will instruct it to process Internet traffic in ways that reduce traffic congestion. A layered system that allows more efficient distribution of processing functions and data elements leads to a reduction in transmission and switch congestion (U. S. Patent 5,602,991: "System for Managing Network Computer Applications," February 11, 1997).

There is a wide range of information applications such as database management, process monitoring and control, and information services management that can add value to the whole Internet process, Berteau says. "By integrating the computer processing function with the control functions of the network, Internet traffic can be managed more effectively."

COPYRIGHT 1998 Nelson Publishing
COPYRIGHT 2000 Gale Group