Juniper Networks failed to protect the London Internet Exchange (Linx) from an outage yesterday, a spokesman has confirmed.

At approximately 4pm, traffic transported over Linx’s two local area networks (Lans) – which route the data for most ISPs in the UK – was hit by an outage, forcing numerous providers to find alternative means to keeping the UK internet online.

A spokesman told Computer Weekly this morning the cause was an internet loop back in an external network, which affected both Lans at Linx. However, the Juniper-based Lan was supposed to have built-in protections to stop such an event taking it down.

“When this happens to the major Lan, there is nothing we can do and it will affect traffic,” said the spokesman. 

“However, the Juniper Lan does have technical protection which should have prevented this.

“We have raised it with Juniper and are going through a detailed analysis with their support teams.”

He insisted the recently installed Juniper PTX packet switches were not related to the outage, in a bid to quash rumours the deployment had gone awry.

The spokesman also said Linx didn’t believe a distributed denial of service (DDoS) attack was responsible and now the task to find the origin of the outage was being executed.

“It is now a question of identifying the source,” he said. “In the past it would have been very straight forward, but now we need to look at two networks as to whether it was the member concerned or the layer two provider.”

“We will be speaking to both.”

Linx was stable from 6pm yesterday and didn’t experience any more issues overnight.