Thanks for the update, Mick, also to you, Andrew, for the information from AAISP's perspective.

This is sounding like a fault affecting a large number of customers when added up across all ISPs using BT Wholesale.

Fault is probably the wrong word, network may be within spec, don't have latency specs for WBC backhaul to hand.

An issue is probably a better way to approach it. Be interesting to here what the resolution is, though I remember back in the early ADSL days this sort of thing was more common and then by magic it would vanish.

In reply to a post by MrSaffron:

Fault is probably the wrong word, network may be within spec, don't have latency specs for WBC backhaul to hand.

An issue is probably a better way to approach it. Be interesting to here what the resolution is, though I remember back in the early ADSL days this sort of thing was more common and then by magic it would vanish.

I accept that broadband is a contended product, and the effects of backhaul contention may show up in end-user connections. I could accept a graceful degradation to higher latency and lower bandwidth per user, though I appreciate it is likely impossible to implement traffic management that cleanly in a network between the ISP and the customer.

What has happened for three consecutive nights is a sudden significant increase in latency causing considerable jitter on an almost idle connection. My NTP servers are far from happy about it, and I suspect the line would be unusable for VoIP. If it happens again, I'll run some VoIP tests to try to quantify how bad things are during periods of degradation.


There's been no inkling of this kind of issue until this week - the latency graph on my monitor shows a straight line from my switch to FTTC in January until this occurred. I would expect upgrades to be implemented in the core of the BT Wholesale network long before substantial degradation of service became a nightly event. Certainly, this gives the impression that some link or device is hitting 100% utilisation.

The sudden onset of this problem and the lack of graceful degradation in end-user experience makes me suspect it is a consequence of some sort of failure or degraded operating condition. That's why I used the word 'fault'. However, out of deference to BT Wholesale, I can go with the word 'issue', so long as I can hold out hope of some sort of resolution.


As you say, it would be interesting to discover what the root cause is, and what resolves the issue.


I hold out hope that Zen will install a PoP in the Flitwick exchange, meaning my traffic doesn't have to pass over the BT Wholesale network. Realistically, though, there are likely to be many more attractive options for Zen when it comes to expanding their network. Flitwick is a fairly small and overwhelmingly residential town, which is currently an island for FTTx surrounded by exchanges where no FTTx commercial deployment will take place.

In reply to a post by pcoventry76:

Not often you get 3 ISP's all replying to you with updates

Good stuff!

Just so long as I don't get a bill from all three.

Seriously, the co-operation shown in this thread is very helpful, and will hopefully help move this issue towards resolution.

Just as a matter of interest, have you done a tracert on your connection before, during and after your spike?

There was no evidence of routes changing, though the way Zen's setup is configured, the BT Wholesale network is wholly transparent. The first hop to respond after my router is losubs.subs.dsl<num>.wh-man.zen.net.uk

There's no evidence of a spike this evening.

We've not seen any latency problems since thursday evening, so looks like it may have been fixed. I'll see if we have an update or further information from BT...

OOI, our monitoring should normally pick this kind of problem up and publish it on: http://clueless.aa.net.uk/congestion.cgi

It didn't actually work this time around, we know why and will get it fixed, so feel free to bookmark the page for future reference.