Strategy shift cures IP network congestion

Liesbeth Evers explains why quality of service is no longer the key.

Performance and utilisation remain the big issues in IP network infrastructures, according to Giga Information Group. And traditional concerns about quality of service (QoS) have been supplanted by a new focus on reducing costs and improving performance by keeping traffic down.

Will Cappelli, network technology research fellow at Giga, believes that tried and trusted ways of dealing with network congestion, such as monitoring QoS, no longer fit the bill. According to Cappelli, technologies have emerged that can enhance performance with less disruption to the network they are managing.

"The fear that networks will become congested is no longer justified," he said. "Performance, reliability and predictability remain issues for the IP protocol, but this is no longer interpreted as a congestion problem but a function of the IP protocol and its associated algorithm, the Border Gateway Protocol [BGP]."

The growth of switched networks has pushed pure IP to the periphery so that it is more a glue than a transport mechanism. As a result, networks have become more articulated, which makes billing, performance and security monitoring complex issues. Remote monitoring is necessary, but much too restrictive and resource-hungry to be used effectively.

At the same time, renewed attention to network costs has focused on limiting the amount of network traffic, particularly to relatively expensive virtual private or wide area networks.

Data compression techniques can offer no further relief, as their practical limit has been reached. Claude Shannon laid the foundation of all phone communication in the 1940s with his mathematical theory of how to maximise the amount of information sent while correcting distortion on the lines.

"In other words, all the classically available mathematical structures for stripping out data streams have been used one way or another," explained Cappelli.

So what does this mean for enterprise networking? Cappelli believes we need to reduce the amount of traffic running over and between networks. For the remaining, minimal amount of traffic, network managers should make the best possible use of relatively expensive network resources.

To do this, Cappelli advised network managers to go beyond the Shannon algorithm. Suppliers such as Zeosync, Celterra and Peribit are all bringing post-Shannon compression algorithms to the market in very different ways.

"The new network optimisation algorithms focus on intelligent routing and switching, supplementing the capabilities of IP and BGP," said Cappelli. "These algorithms are cost-based, which brings a critical cost reduction. Suppliers such as Routescience, NetVMG and Sockeye Systems were the first to offer new levels of intelligent route selection."

In addition, new network performance monitoring and management systems can identify the best way to apply modern compression and optimisation algorithms. Products from suppliers such as Chevin, Niksun and Inmon can handle modern articulated networks without adding the burden of remote monitoring.

Other new integration tools have been introduced to bring all this together. Valaran, Olive Systems, Fuego and Longitude Systems have started to offer new kinds of open source integration technology.

"That is the recent trend in network technology," Cappelli said. "It basically means you should keep in mind that managing networks has shifted from differentiated QoS to managing for cost minimisation."