Tiscali broadband offers service quality for voice

Internet service provider Tiscali has launched an ADSL service with guaranteed quality, designed to support voice-over-IP services at remote offices and allow teleworking and distributed call centres. The service, starting at £849 per year, is functionally equivalent to leased lines costing £7,000 per year, the company said.

Voice services can be disappointing, because they lose quality when other traffic is on the network. "If you are connected to voice, then go into Outlook and download a presentation, voice quality may suffer," said Lance Spencer, product director at Tiscali. The company's service addresses this by reserving a channel for voice traffic.

Tiscali is one of the few ISPs to use Datastream, a wholesale broadband service sold by BT with quality-of-service (QoS) features, said Spencer. "We consume about 75 to 80 percent of BT's Datastream capacity, and we're selling 10,000 lines a week." Most other ISPs use the IPstream service from BT, he said.

The company has also enabled its Cisco equipment to use the MPLS protocol, and provide QoS. The router at the customer site will set up two queues of data packets, one with QoS, and runs all the voice traffic through the protected path.

Customers pay a setup charge, and then a monthly fee. This starts at £60 for a service which supports one voice call at a time, by combining a dedicated 50kbps channel with 256kbps of best-efforts data at a 10:1 contention ratio. Other options include better contention ratios and more data channels, but the maximum on one ADSL line is four. Spencer explained this is because each dedicated voice line takes a 50kbps chunk out of the uplink channel. "The uplink is only 256kbps. If you want more than four simultaneous calls, you have to buy two lines."

At the moment, customers also have to buy a Cisco router. Other brands will be certified in the future, said Spencer, though he warns it will never include really cheap sub-£100 routers. "Prices will come down to about £200," he said.

Running the service over BT's Datastream means Tiscali is in fact layering its service on top of ATM, a protocol that MPLS-on-IP has been expected to supercede. "We could go MPLS all the way to the DSLAM, [in the telephone exchange] when the local loop is unbundled," said Spencer. "But no one is going to unbundle all of BT's exchanges. The nice thing about Datastream is that it is potentially available in all exchanges."

Virtual call centres will allow time-based staff to work just the peak hours, said Spencer: "IP call centres have been possible for a number of years, but would cost £7,500 per year per person. Functionally what the user gets is the same." He conceded that service contracts were different. "Problems with leased lines get fixed in four hours, while DSL issues are fixed in two days."