TelstraClear key clients business manager Rob Julian modestly suggests his company might be coming close to the much sought-after high-quality widespread IP voice-and-data network.
Computerworld sought the telco's views after a remark by Telecom’s Rhoda Holmes that no suitable complete package model exists for the implementation of such a network.
“We have implemented a fully operational IP network which we consider provides carrier-class service to us and our customers,” Julian says, which include some very large customers.
The key factor for TelstraClear, he suggests, was “getting an integrator to bring together what we regarded as best-of-breed components for each role”, such as the Juniper switches in the core and Extreme switches on the edge.
“The significant issues are, I think, more to do with service to the customer than the technology itself”, he says.
A straightforward telephone or data network concerns the carrier chiefly with levels one and two of the protocol stack: the pipes and the switching. IP moves above that, he says, and brings a supplier in contact with what customers are doing with the network to serve their business.
“We’re integrating right into their business, into their LANs. We can come closer to the customers and bring the lessons we’ve learned into their business.”
Quality of service on IP is a major issue, he says. “And we feel we can deliver on that. We have customers transmitting broadcast-quality video over our IP network."
He says the company worked closely with Ericsson on putting together the requirements definition, specifying what grades of service customers were likely to want for each application.
“Our Extreme switches support eight different traffic priorities and that allows us to do application-level traffic shaping.”
Email, for example, would normally be a low-priority application with interruptions and delays on a certain scale tolerated.
At the other end of the scale, voice, is the most critical traffic, he says. “Video I would put one grade down from that, because the eye is more forgiving of brief glitches than the ear is.
“The way you design the network is crucial; whether you put your intelligence in the core or on the edge.” This has an impact on the trade-off between latency, the delay to a signal, and “jitter”, the tendency of packets travelling by different routes to arrive in the wrong order.
TelstraClear has opted to put the intelligent switches on the edge, “closer to the customer”.
Security is ensured and interference eliminated with a scheme of “reserved bandwidth”. A user’s connection is exclusively theirs and no-one else’s traffic strays into it.
Does this not reduce the efficiency of a packet-switched network, restoring some of the idle capacity that exists on a circuit-switched connection? “That inefficiency might be a problem if we didn’t have the capacity,” Julian says.
TelstraClear’s network has “capacity for huge growth” in its present mode of use. “And we can get more in the future simply by lighting up new wavelengths on the fibre”.