The debate over net neutrality will become increasingly heated as cable operators realise that advanced video and voice services from online providers are beyond the control of cable operators and their closed networks, analysts predict.

ABI Research believes that the introduction of network-based control, such as personal video recorders, start-over, time-shifting and video on demand, will see a significant increase in the amount of spectrum set aside for on-demand services.

"As customers interact using remote controls to send signals via set-top boxes, bandwidth requirements will continue to increase for cable operators," said Stan Schatt, vice president and research director at ABI.

"There is also potential that the spectrum requirements for DOCSIS [Data Over Cable Service Interface Specifications] data will explode, removing yet another chunk from the amount available."

Schatt believes that the burden of supplying a broadband pipe to support these services falls on the cable TV operator.

Although this is fuelling the net neutrality debate, broadband bandwidth on cable TV networks will have to expand in the near future to accommodate customer demand.

Any expansion of the bandwidth dedicated to broadband will be that much less bandwidth used for revenue-generating video services.

"One new service that could impact bandwidth combines voice and video for two-way video calling," said Schatt.

"Operators are concerned that services such as this, along with online gaming, will place enormous strains on upstream bandwidth capacity.

"The argument from cable and telecoms operators against net neutrality focuses on network strain caused by bandwidth-demand increases, which operators cannot control.

"If the customer uses data services for basic surfing and email, demand for bandwidth is not a hindrance to the broader network spectrum capacity.

"But when customers use voice and advanced video services from online providers, the amount of data downloaded will cripple the bandwidth capacity of a network."