Broadband News

AAISP gets TalkTalk to fix overhead issue affecting VDSL2

Some AAISP customers are now back to enjoying the full speed of their VDSL2 circuits, the problem was most noticeable on the faster VDSL2 lines i.e. connecting at 60 Mbps and with actual throughput from speed testing running several Mega bits per second below that people would expect.

AAISP after some testing of their own, got TalkTalk to do the same testing and after some test changes that fixed the problem all the AAISP TalkTalk backhaul VDSL2 connections have had the change rolled out to them. Whether this improvement/bug fix affects all TalkTalk Wholesale VDSL2 circuits or just AAISP we don't know, but we would presume TalkTalk has checked and implemented any changes needed for all its wholesale customers.

The fix is described as a change to "overhead accounting mode in use for VDSL customers." i.e. the throughput was lower than would have been expected. On BT Wholesale VDSL2 circuits the general rule is that maximum throughput should be ~96% of the sync speed, but there are some combinations of ReTx that do see the maximum throughput dropping to ~91%.

If you are an AAISP whose speed has dropped and sync speeds are at their normal level and nothing has improved yet, then restart the authentication on your router or the more old fashioned turn off and turn on should see the line pick up the changes.

Comments

I reported this problem a few months ago to AAISP they just told me to live with it which was correct at the time as it wasn’t below the BT threshold speeds. However It was good of AAISP to acknowledge the speed drop to me when they found the fault. I’m now back up to full speed.

  • 2bagstew
  • 2 months ago

This also affected Uno customers, I was affected, seeing ~75Mbps drop to a maximum of 69Mbps. It didn't seem right but as nothing else was affected I like many I expect just accepted it or didn't notice it, but thankfully some people did pursue it and both Uno and AAISP were onto TT about it, in Uno's case for many weeks. I think the problem was not enough examples for TTto take it seriously. You have to wonder why TT didn't notice the reduction on their network, perhaps they did and liked it or thought their new network (which introduced this) was performing really well!

  • philipd
  • 2 months ago

I believe this isn't/wasn't affecting direct TT customers which suggests TT are still using the "old" network for such customers. Probably best to iron out all bugs (which this seems to be) before moving all customers en-masse to the new one.

  • baby_frogmella
  • 2 months ago

The direct customers don't have PPP concentrators to deal with, those are likely where this configuration error was made. Nothing to do with the 'new' network per se.

  • CarlThomas
  • 2 months ago

this happend this morning, not sure if this relates to the news. im on BT
Today 09:22:07 Sent KCI email @gmail.com 2018-07-06 09:22:02 DSL line up (down 11 minutes) KCI
Today 09:22:06 Tx rate (adjusted) 72018256 to 78282292 (rx 20000000) -Auto-
Today 09:21:25 Test line called (Q)

  • RedBull2k14
  • 2 months ago

@Carl
Then perhaps you’d like to explain why the issue did not exist on the “old” network TTB based lines on AAISP and UNO when they tested lines on both networks simultaneously?

  • baby_frogmella
  • 2 months ago

Here you go Carl:

"With the help of TalkTalk, this evening we tested a circuit via the old network. Although the latency increased (from 6.4ms to 11.8ms) the throughput as measured by using the iperf3 tool showed an increase from 67.4Mb/s to 71.9M/s. (This is a line with a 75.6M sync rate)"

https://aastatus.net/2530

  • baby_frogmella
  • 2 months ago

Poorly explained on my part. New PPP concentrators. The direct customers don't use them so makes no difference to them which network they are on.

  • CarlThomas
  • 2 months ago

@RedBull2k14 - that's something different - contact support if you're having problems, but that looks like your line resynced at a higher rate.

  • andrewhearn
  • 2 months ago

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