Voice-over-IP could take 20 years to see off the old steam telephone, according to HP networking chief John McHugh.

The 'slow retirement' of the old PBX phone shows how long network infrastructure takes to change, he told a Netevents forum in Garmisch, Germany.

'Every year for at least five years we have been told VoIP is about to happen. It isn't.

'It is going to be a slow erosion [of legacy telephony] over 15 to 20 years,' said McHugh, VP of HP's Pro-Curve networking.

He predicted that by 2010 10Gbits/sec links to the desktop over copper lines would be available to a privileged few, but 1Gbits/sec would be sufficient for most links between company premises and metropolitan trunk lines.

Mobile roaming will be 'transparent and robust' and video calling from handhelds will be widely available and largely unused. 'That's because people simply don't want it,' McHugh said.