Business ISP Andrews and Arnold has strongly criticised BT's new 21CN network backbone as unable to cope with current bandwidth demands.
The small firm runs a network status blog for its customers, and this morning came out with some harsh words for BT.
"It is quite clear to us that BT's 21CN network simply cannot cope with demand at present," Andrews and Arnold said.
"We have clear evidence of a significant portion (around half) of BT 21CN lines that we have showing serious loss and latency problems within BT."
21CN is a multibillion-pound backbone upgrade that moves all voice and data traffic to a common IP infrastructure. It is being activated nationwide to improve theoretical maximum downstream ADSL speeds to up to 20Mbit/s, from up to 8Mbit/s. In reality the improvement is significantly less, but BT has claimed the upgrade will also make huge savings.
Andres and Arnold gave more details of its gripes.
"The problems are high latency and some packet loss, mostly during the day where there are any high levels of streaming media," it said.
"This has a major effect on the performance of internet access generally and is very serious for anyone using interactive terminal sessions and VoIP. The issues relate to specific BRAS/metro-nodes within BT and so are clearly not our end or the link from us to BT."
The firm challenged BT to make a statement on the problems. This afternoon a spokesman told The Register: "BT's 21CN offers more than adequate capacity, using the latest technologies.
"We offer a range of options to our customers, allowing them to match the price they want to pay to the capacity they require. We are always keen to understand and resolve customer issues and have been in dialogue with Andrews and Arnold around their specific concerns. We are of course open to further discussions with Andrews and Arnold via the normal customer service routes - our door is always open."
Andrews and Arnold has a track record of being among the first ISPs to speak out over problems at BT. It'll be interesting to see if anyone else has criticism for 21CN. ®