Do BT have the bandwidth?

coreservers · Aug 18, 2009, 21:38:55

judging by the munbers of people suffering huge thruput losses, and high pings, despite good sync rates and even decent ip profiles. Could it be possible that BT have run out of bandwidth?

I've seen the hard face of traffic shaping having been with sky connect, which is not really a native sky package, but a rebranded bt one. I was getting 5.5mb up until 4pm, then suddenly, I was as low as 250-300k. up until 11pm.

This was all because sky oversold the package, and only bought enough bandwidth to cover their estimates. But I have heard say, that BT just do not have enough available bandwidth to cover the current needs of the network in general.

If this is the case, how long before IDNet have to traffic shape like most of the large providers?

Simon · Aug 18, 2009, 21:47:00

We've not heard any plans of that nature, Core.

Lance · Aug 18, 2009, 22:47:15

I suppose that BT could enforce ISP wide traffic shapping simply by leaving their network congested!

Simon · Aug 18, 2009, 22:59:15

They're doing it anyway, it seems.

dujas · Aug 19, 2009, 00:32:08

I would think it's unlikely "BT have run out of bandwidth", there will at times be localised exchange/node problems, but I would of thought the services BT Wholesale provide would have contractual obligations for both parties involved.

You have to remember that this forum can distort the reality of an ISP's situation, in that generally people only post in this section when something goes wrong.

Sebby · Aug 19, 2009, 00:38:20

Yep, that's a very good point.

Simon · Aug 19, 2009, 00:57:35

Indeed, it is.

Rik · Aug 19, 2009, 08:36:28

OTOH, I have long had a feeling that BT are not investing in sufficient backhaul. After all, we've lived with congested VPs for as long as Max has been around. I believe BT keep their costs as low as possible and only react to bandwidth issues, not anticipate them. Right now, I sense that their investment in FTTC is at the expense of current ADSL products.

coreservers · Aug 19, 2009, 21:12:21

well, I'm begining to think traffic shaping is coming
I'm currently sitting again at 1.5mb, but at 4pm I was at 5.4mb

Connection Speed 7833 kbps 1082 kbps
Line Attenuation 40.5 db 18.9 db
Noise Margin 8.4 db 8.5 db
as you can see for once nothing wrong with router stats.

Very similar to sky connects shaping precisely at 4pm. Will be checking tomorrow at 3.45 and again at 4.15

pup · Aug 19, 2009, 22:38:33

What the hell is 'backhaul', 'virtual path' and 'pipes' any way

Simon · Aug 19, 2009, 22:59:12

I would explain, but I'd be wasting both of our time, as it would be complete nonsense!

pup · Aug 19, 2009, 23:16:14

right ok

Sebby · Aug 20, 2009, 00:45:22

This should help.

http://kitz.co.uk/adsl/equip.htm

esh · Aug 20, 2009, 13:29:56

I have a friend in portugal who, precisely at 6:30pm every day, has their gaming pings go immediately from ~150ms to... something amusing. On the order of 270,000ms to 430,000ms. It really is quite astonishing. Early hours of the morning and all is well again. I do wonder about bandwidth shaping for something sudden like that. I don't see why things would be routed differently depending on time of day, but then I am not an ISP.

Sarah · Aug 20, 2009, 14:53:07

Quote from: Sebby on Aug 20, 2009, 00:45:22
This should help.

http://kitz.co.uk/adsl/equip.htm

I wondered what backhaul is too, can you explain, if the Kitz graphic was adapted for WBC - would the backhaul from the local exchange go to one of the twenty 21CN nodes, e.g. the Milton Keynes one, and then would the part to the ISP look similar to as it does in Kitz' graphic? No worries if there's no simple answer.

I was looking at this page at AAISP AAISP Status Page: [closed] Milton Keynes RAS (20+21CN), and reckon my exchange is on this MK node too, as I lost the connection yesterday (first time for as long as I can remember), at just the point when it indicates 21CN dropped here as well as 20CN. It came back again OK.

Rik · Aug 20, 2009, 14:54:21

Quote from: esh on Aug 20, 2009, 13:29:56
I have a friend in portugal who, precisely at 6:30pm every day, has their gaming pings go immediately from ~150ms to... something amusing. On the order of 270,000ms to 430,000ms. It really is quite astonishing. Early hours of the morning and all is well again. I do wonder about bandwidth shaping for something sudden like that. I don't see why things would be routed differently depending on time of day, but then I am not an ISP.

It may not be routing, but simply congestion, only a tracert would establish which.

Rik · Aug 20, 2009, 14:57:48

Quote from: Sarah on Aug 20, 2009, 14:53:07
I wondered what backhaul is too, can you explain, if the Kitz graphic was adapted for WBC - would the backhaul from the local exchange go to one of the twenty 21CN nodes, e.g. the Milton Keynes one, and then would the part to the ISP look similar to as it does in Kitz' graphic? No worries if there's no simple answer.

Backhaul is, essentially, the connection between the DSLAM or MSAN at the exchange and the BT network, Sarah. It's exact routing and interconnection is probably only known to BT, but my own guess would be that exchanges have always fed to concentrator points in one way or another, a bit like tributaries running into a river. With WBC, the process seems to have been formalised and concentrated on the 20 nodes but, like the wire between your router and the exchange, my own guess would be that there were still a number of junction points along the way.

Sarah · Aug 20, 2009, 15:30:15

I got a bit further (google image search) with the two drawings on this UCL page: Damon Wischik - cost of P2P distribution. The first is IPStream and the second 21CN. Only drawings, but shows a bit more.

Rik · Aug 20, 2009, 15:35:04

Thanks for that, Sarah, the metro nodes fit with my belief that there are intermediate concentrator points.

Sarah · Aug 20, 2009, 19:18:56

More explanation of the Metro and Core nodes on this SamKnows page (about half way down):
High level 21CN network structure

Just exploring - to get the gist of it

- no real idea what I'm looking at.

Rik · Aug 20, 2009, 19:23:41

It's all very mystical really, isn't it. A new learning curve for us, just as Max was.

Colin Burns · Aug 20, 2009, 21:08:42

Quote from: Rik on Aug 20, 2009, 14:57:48
It's exact routing and interconnection is probably only known to BT

come on rik not even BT or any respectful tech understand how BT routes traffic. as when they did the routing setup the bought the idiots guide to routing traffic and still did a high quility BT job on it

think im ranting a little but my net connection is annoying as i constatly have to click refresh 4 5 times to get a page to load