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Internet needs better simulation models, speakers say

Posted: 02 May 2002 ?? ?Print Version ?Bookmark and Share

Keywords:simulation? broadband? Internet? communication?

Simulation models that relate applications to bandwidth provisioning have a long way to go before a multiservice Internet is easy to use, according to speakers at the opening sessions of the International Conference on Communications' 50th anniversary gathering. Development of such models will determine whether service providers ever deliver broadband service profitably, said Will Leland, chief scientist of the Internet Architecture Research Labs at Telcordia Technologies Inc.

"The basic flaw in the broadband business model we've seen time and again to date, is that delivering just bits does not pay, but without reliable bit delivery, nothing else pays either," Leland said.

The ideal model for consumers using the Internet would be a client-based agent that could dynamically request more bandwidth based on the type of service the customer desired, Leland said. But no reliable model relating protocol layers to application layers exists that can assess how bandwidth is being delivered, he said.

In most cases, "applications don't know what services they need and can't request it if they did," Leland said.

Problems in moving to a next-generation Internet are not limited to consumer applications, Leland said. End-to-end networks do not have the synchronization required for large-scale distributed computing, for example. Many scientific users are interested in "grid computing," such as the National Science Foundation's TeraGrid program. But Leland said the ability to successfully run grids depends on each device being configured exactly correctly, and never going down, limiting a practical grid's useful time to more than a few hours currently. Creating successful grids from the current Internet is "excruciatingly hard," Leland said.

Ravi Sethi, president of Avaya Labs, said in a Monday (April 29) keynote speech that the enterprise can serve as a well-characterized testbed for perfecting Internet applications. Sethi directs the research arm of Avaya Communications Inc., the enterprise-oriented equipment spin-off of Lucent Technologies Inc. Voice-over-Internet Protocol is one example of a technology that still has problems scaling globally, particularly in a multiuser conference call environment, but can be defined with tighter quality-of-service constraints in the enterprise.

Sethi said that the client-oriented Session Initiation Protocol, when used as an enterprise enabler of VoIP services, often is the easiest way to bring in low-latency packet services that are later extended to a public-networking environment.

Cost of service broached

While past IEEE conferences have avoided talking about financial constraints of services, present market realities led many speakers at ICC's opening day to address the costs of deploying services. Adam O'Donnell of Drexel University's Electrical and Computer Engineering Department described a new pricing policy for differentiated services over IP, in which flags in an IP header are established and fed back to the user, setting a price based on the raw amount of bandwidth consumed, a price due to the preferential levels of services, and a price due to the buffer resources occupied and packets dropped.

The advantage to the bargain hunter, O'Donnell said, is that service providers do not have to charge the top QoS rates if no other customers are standing in line for service. If the user is the only one requesting preferential service, for example, the price can go back to a lower QoS level because the IP packets do not have to take any "cuts in line."

"Each router adds an additional cost constraint, but the end user only sees one set of pricing policies set by his particular service provider," O'Donnell said. "This could be implemented fairly simply."

? Loring Wirbel

EE Times

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