IP telephony is beginning to have a significant impact on the way companies deploy their IT systems, according to a new report from Burton Group.

Growing demand for the technology, along with mainstream use of SSL VPNs, data centre consolidation and other trends, is combining with disruption in the service provider industry to shake things up for enterprise IT planners, the report, VantagePoint 2004-2005 Network and Telecom Strategies Overview, said.

"Service providers are striving to adapt to disruptive effects of IP networking, an outmoded regulatory framework (that still doesn't recognise the existence of the Internet), and developments that make many of their business models obsolete," said Burton Group research director David Passmore. "The result will be a challenging environment for enterprise network planners and operations staff."

Voice over wireless LANs is changing the way companies deploy wireless access points, with a new emphasis on dense AP deployment, which can provide better and more reliable performance, the report said. In turn, is requiring companies to look at products that can centrally manage WLAN channel assignments and power levels. Public IP telephony services are also becoming a significant force, particularly for smaller organisations and those who don't require full enterprise-class sets of features.

This trend is creating its own technical problems, such as the emergence of isolated IP telephony islands that can't communicate with one another, and lack of interoperability among Session Initiation Protocol (SIP) vendors.

Companies are deploying SSL-based VPNs more widely, leading to a boom of sorts in the SSL business, the report said. Multiprotocol Label Switching (MPLS) VPNs are becoming popular for site-to-site connectivity.

Data centres are moving to a consolidated architecture around virtualised infrastructure devices for the front end, blades to reduce space requirements and interconnection costs, and IP/Ethernet-based back-end storage, the report said. Larger enterprises are increasingly locating their data centres at Internet data centres for peering.

Large businesses are seeing a stronger case for carrier-class technologies such as optical wavelengths and multihoming, but prospects for other advanced services, such as interprovider MPLS VPNs, quality of service and IPv6 transit are further away, Burton Group said.