I can't really say how much higher priority business users had over my residential connection since my connection was always line speed with low latency. But in any case it appears from this thread that the priority system, if any, does not mitigate exchange congestion for business users.

Again, I don't follow your logic. Are you sure you grok what priority actually means in this context? You shouldn't conflate it with shaping or a bandwidth budget.

In reply to a post by richi:

Again, I don't follow your logic. Are you sure you grok what priority actually means in this context? You shouldn't conflate it with shaping or a bandwidth budget.

Yes, I know what priority means, and I saw no evidence of my packets receiving a low priority on TT res, certainly not to the extent that my throughout or latency was impacted. If my connection's packets were constantly delayed to allow TT bus packets through I would expect to see some kind of impact.

But that's my point. If there's no significant congestion in your area, you won't see any effect.

In reply to a post by richi:

But that's my point. If there's no significant congestion in your area, you won't see any effect.

If that's the case, given how rare congestion is on TT, the whole priority thing seems pretty pointless.

Not so much. Where there's plenty of spare headroom, priority still has benefits in terms of latency --particularly in consistency of that latency.

Quite apart from technical benefits, there are also intangible "marketing" benefits, particularly when selling to businesses. And, as a small business connecting to a TT 2+ MSAN in a rural exchange, I'm willing to pay a bit more for that peace of mind. YMMV.

In reply to a post by richi:

It's inconceivable that local congestion should slow you down this much if it was provisioned correctly, no?

Just because TTB runs at at higher priority than the residential service doesn't mean its immune from slowdowns in the event of exchange congestion...i know this from experience as I'm on TTB & my neighbour is on TTR and we both got slowdowns at peak times for a few months until TT added extra backhaul capacity. But my ping times are slightly (~5ms) better than my neighbours d/t my service taking a different routing to TT's servers, this would explain the 'priority' part. I can assure you that your TT resold service would also suffer at peak times should your exchange get congested so no need to be smug about it.

Anyway i have my doubts if the OP is suffering exchange congestion because he's getting yellow spikes on his line 24/7 which indicates a possible line fault...if it was exchange congestion only, there would no such spikes at 4am. Its also possible that the OP's fibre links from the FTTC cabinet to the exchange are congested in which case it makes diddly squat difference if you are paying £70 p/m with AAISP or £2.50 p/m with TTR. Though i suspect AAISP would be better at spanking Openreach's bottom than TTR.

In reply to a post by baby_frogmella:

Just because TTB runs at at higher priority than the residential service doesn't mean its immune from slowdowns in the event of exchange congestion

That's a wise reminder that no service is uncontended unless it is sold and provisioned as such, with a Service Level Agreement giving the customer remedies if a guaranteed level of service is not met. Consumer and business broadband services has no such SLA and can only be sold at a low price point because they are contended.

The providers have the difficult job of trying to provision sufficient capacity to prevent significant visible contention without expensive upgrades proving unnecessary. Some upgrades can be done quickly, whereas others have a long lead time.

It is unlikely that any provider would operate their network on the basis of "let all business traffic through before any residential traffic". In any event, the peak bandwidth requirements of residential and business services typically do not coincide, though there is never any certainty over this.

In reply to a post by David_W:

It is unlikely that any provider would operate their network on the basis of "let all business traffic through before any residential traffic".

In fact, that's basically what BT Wholesale does. Each defined priority level is assigned its own queue. Traffic in lower-level queues doesn't get delayed unless there's congestion.

I assume TT is similar, but I have no way of knowing.

Edited by richi (Wed 14-Oct-15 18:55:32)

In reply to a post by baby_frogmella:

no need to be smug about it.

Not very collegial. Les trolls ne seront pas aliment�s!