Note: This article has been updated with comments from NBN Co since it was first published.
news Early trials of National Broadband Network fibre connections through several different Internet service providers have shown speeds topping out at 95Mbps, five percent slower than the NBN’s overall theoretical limit of 100Mbps.
In a post on his blog yesterday, Exetel chief executive John Linton, whose company was one of the first to go through NBN Co’s on-boarding process and be ready to provide services over the network, revealed that the first dozen or so of Exetel customers had now had their NBN services connected and were able to use their connections.
“A surprisingly large percentage of the trial orders are for 100Mbps/40Mbps services, and of those we have contacted/have contacted us, the service is delivering around 95Mbps down and 32Mbps up, with a 10ms ping time,” he said. “As the NBN Co network would currently be as under-utilised as it’s ever going to be those results seem likely to be the maximum achievable in the near term.”
The news almost precisely mimics the results achieved by PCRange chief executive Raaj Menon, who moved suburbs in Adelaide in order to make sure he could get the NBN early.
In late June, after his NBN fibre service was connected, Menon noted in a statement issued by his service provider, Internode, that he was achieving speeds of 95.5Mbps downstream and 35.5Mbps upstream, with ping times of about 3ms. In a separate blog post, Menon added that he ran a variety of speed tests, average around 94 to 95Mbps down and 35Mbps up. “It is close enough to the advertised speeds,” he noted.
A NBN spokesperson responded to the issue by noting that the company was building a network designed to achieve downlink speeds of up to 100Mbps at the wholesale Layer 2 (Ethernet) level.
“Most speed tests operate at the Layer 3 (Internet Protocol) level and the extra packet overhead will typically result in lower measurement speeds (depending on the type of traffic),” they said. “We point out that the speeds actually experienced by end-users will depend on a number of factors including, in part, protocol factors, the retail broadband plan they choose, their ISP’s network capacity, the number of simultaneous users on the service, the server’s equipment and configuration, their equipment and their in-premises connection.”
In a recent blog post, Internode chief executive Simon Hackett noted that the ISP’s experiences in Tasmania showed that each point of interconnect region located around Australia would need at least 200Mbps of capacity supplied to it (which NBN Co refers to as the ‘Connectivity Virtual Circuit’) in order to ensure most customers would be able to access the maximum speeds under their NBN connections when they wanted to use them.
In short, that capacity is shared between customers connecting to a certain point of interconnect.
Other typical technical limitations on network links include factors such as the speed of serving data from storage, or other, non-NBN links in between the data being downloaded and a customers’ own PC. Inefficiencies in a customers’ own router can come into play.
While this sort of theoretical limit on NBN speeds isn’t really unexpected (I mean look at ADSL — ‘theoretically’ it allows up to 24Mbps, but few actually get those speeds), it is interesting to see such similar results across ISPs. Is there some kind of 95Mbps bottleneck in the NBN infrastructure which is impossible to push past? It seems there could be many factors to consider. In the meantime, of course, I personally — and I suspect almost everyone else — would be quite happy to get “only” 95Mbps speeds … at least until the gigabit upgrade eventually comes along ;)