Congestion Isn't Just VM Only
 

With the exception of those on Talk Talk, Sky and some Zen customers, all fibre services at the moment use BT Wholesale. BT Wholesale have some congestion issues on their network, in some cases fixable via configuration changes but in some cases requiring new hardware and fibre.

Think Broadband Story
RevK of Andrews and Arnold
AAISP Congestion Report
Plusnet Congestion Report

These issues are somewhat inevitable given increased service speeds, but for BTWholesale are disappointing as these guys make their money selling bandwidth to ISPs, so it's pretty ridiculous them not upgrading their network to keep up with demand from their customers given they're paying per Mbit.

The indignation from Neil McRae was a bit of a PR disaster too.

Re: Congestion Isn't Just VM Only
 

Refresh my memory here - don't ISPs buy "pipes" of some fixed bandwidth to exchanges/offload points whatever they're called, and historically it's been these that have become full as a result of the ISP not buying enough capacity rather than the underlying infrastructure itself filling up?

If so, how does what we're seeing now differ? So far all the above links just point to monitoring consumer endpoints, with nobody seeming to look at any internal endpoints within the BTw network, such as an old TBB monitor I'd set up ages ago (before TBB stopped me being able to set up/modify my monitors) to a BT Retail RAS

Re: Congestion Isn't Just VM Only
 

An ISP controls their bandwidth, they know if they've capacity issues and they know which customers map to which endpoints on their network. If they see some customers having strife while others aren't on the same MSILs they can drill down, as Plusnet and AAISP do, to exchange level.

They can also go to BRAS level as they know which BT Wholesale BRAS customers connect via.

From that lot they can tell, if so minded, whether the issues are on an entire BRAS, on a geographically close group of customers but on different exchanges, pointing to an issue at a metro node or BRAS LAG, or at an individual exchange, if some customers at an exchange an SVLAN congested, if all customers at an exchange showing issues potentially the backhaul the SVLANs live on is full.

The BTW 21CN network has individual SVLANs mapped to BRAS via metro nodes, so congestion can occur at logical SVLAN level, or at a physical level in a couple of places.

EDIT: Customer <xDSL> Exchange <SVLAN on LAG/GbE/10GbE> BRAS <Ethernet> LAC <Ethernet> ISP LNS

Re: Congestion Isn't Just VM Only
 

The last time I went to BRAS level I got my face slapped!

Re: Congestion Isn't Just VM Only
 

Thanks, that's what I was looking for!

Re: Congestion Isn't Just VM Only
 

You're doing it wrong.

I was about to make an exceedingly tasteless joke but will get my backside kicked and am trying to behave. :angel:

Re: Congestion Isn't Just VM Only
 

:)

Re: Congestion Isn't Just VM Only
 

I PM'd the tasteless joke, Mr A.

Seeing a minimal amount of congestion here; barely perceptible but due to the usually excellent average latency it does show as an increase along with a touch of packet loss.

I have FTTC from Plusnet and BT Retail, so both use BT Wholesale's network and I know that's the common point between them.

Re: Congestion Isn't Just VM Only
 

Do you think that BT/The LLU Cos/VM have managed to build up enough resiliency in their core/backhaul networks to cater for the widespread use of 50+Mbit broadband? Once the prices start to fall I can see a fair few problems emerging

Re: Congestion Isn't Just VM Only
 

For now. On the whole usage per customer is still less than 1Mb/s. Well engineered networks alongside the wider availability and lower cost of 100GbE ports make a difference.

You can shove 20 of these into a single MX2020 chassis.

Re: Congestion Isn't Just VM Only
 

Eep, just actually tested connections rather than a brief look at the TBB meter...

https://www.cableforum.co.uk/images/...2014/03/18.png

http://www.thinkbroadband.com/speedt...4809074931.png

Re: Congestion Isn't Just VM Only
 

Y'know last time I suffered congestion on BT (temporary for about 3 days) it was bad enough to send my download speed down to 4Mbps from 76Mbps yet didn't have any noticeable increase in minimum or average latency, with only the max latency jumping by about 10ms.

Re: Congestion Isn't Just VM Only
 

Makes perfect sense. The way DOCSIS and the Ethernet network where this is happening on BT handle congestion are quite different. Downstream congestion on VM looks kinda similar to the congestion on BT, obviously upstream congestion is completely different as you're comparing a full-duplex transmission medium against a TDMA request-grant medium with buffering done on individual CPEs.

Here's what bad 21CN congestion looks like.

Re: Congestion Isn't Just VM Only
 

Isnt there also the fact that BT use QoS where VM dont?

Re: Congestion Isn't Just VM Only
 

Not on 21CN; that applies to 20CN, the old Colossus ATM network.

Re: Congestion Isn't Just VM Only
 

Tonight's excitement.

http://www.thinkbroadband.com/ping/s...25-03-2014.png

Download speed achieved during the test was - 25.86 Mbps
For your connection, the acceptable range of speeds is 61.86 Mbps-77.33 Mbps

Re: Congestion Isn't Just VM Only
 

Back on Infinity myself, on the Aberdeen Denburn exchange which some providers say is having... problems... Should set up a monitor except a) TBB won't allow me to and b) the crappy HomeHub doesn't accept WAN pings.

Re: Congestion Isn't Just VM Only
 

Denburn should be fine now.

http://status.aa.net.uk/1902

Re: Congestion Isn't Just VM Only
 

Interesting... Co-inhabitants have been reporting packet-loss/gaming lag since the 22nd funny enough, I've not had any real monitoring set up to see where it was, though we did have a BRAS outage a few days ago too.

Re: Congestion Isn't Just VM Only
 

This is fixed as of last night with a new physical backhaul link and enlarged SVLANs.

Re: Congestion Isn't Just VM Only
 

Your place or mine? Got a before/after TBB chart?

Re: Congestion Isn't Just VM Only
 

Mine, and yes.

Last Tuesday:

http://www.thinkbroadband.com/ping/s...25-03-2014.png

This Tuesday:

http://www.thinkbroadband.com/ping/s...01-04-2014.png

Overnight drop was the work being done.

Re: Congestion Isn't Just VM Only
 

Nice.

I've finally gotten round to replacing the dreaded Home Hub of Suckage with my own router imported from my Edinburgh Infinity line - and setting up a new TBB monitor (my account's been broken and not allowed me to create any new monitors for years now...)

https://www.cableforum.co.uk/images/...2014/04/30.png

As I say, Aberdeen Denburn exchange which supposedly had issues recently, and housemates constantly complaining about lag/packet loss and so forth - though I suspect some of that might have been related to the HH5 since it all disappeared as soon as I put my own custom router in it's place.

Seems I'm on an ECI DSLAM now as I now get upstream line stats too, which I didn't used to

Lets see how this goes... Not sure the monitor will stay up too long though, non-static IP and I'm still messing around with the network settings. Used to have average PPPoE uptime of 45+ days in Edinburgh but I doubt it'll manage the same here, even though I'm on the same BRAS.

Re: Congestion Isn't Just VM Only
 

Doesn't look very fine to me:

https://www.cableforum.co.uk/images/...2014/04/25.png

Also, been a while since I checked but it looks like there's load or congestion problems even on the core network from England up to Edinburgh (the following being BRAS')

https://www.cableforum.co.uk/images/...2014/04/26.png
https://www.cableforum.co.uk/images/...2014/04/27.png

Re: Congestion Isn't Just VM Only
 

OK, well since I've already hijacked this thread, I was wondering if you could help me figure out at what level the problems are occurring with my BT Infinity connection.

So what I've figured out so far - firstly, whatever the issue is it's somewhere between my exchange (Denburn) and Edinburgh. That leg reaches saturation pretty much all day from 2pm to 2am now (reminiscent of VM issues I used to get). Download speeds drop from line rate (70Mbps+) to less than 10Mbps at peak times. Latency and packet loss pretty much exactly match your example of "bad 21CN congestion" earlier:

https://www.cableforum.co.uk/images/...2014/04/17.png

Now according to AAISP, Denburn should be fixed. Now I'm not sure what is fixed, and what other variables could perhaps be in play that cause issues specifically for BT, but not AAISP. Nonetheless BT Retail is seeing very low speeds and heavy packet loss, and I'm guessing AAISP is not. Both are BT Wholesale based.

What I also know is the physical pipe between Denburn and Edinburgh is not at saturation, as there are other links (e.g. the ptm.301 "backdoor" network on the Openreach modem) where I can ping some Juniper device somewhere around Edinburgh/Glasgow and receive consistent, loss-free and jitter-free responses throughout the day that do not get worse at peak times. Pinging the PPPoE gateway though, again in Edinburgh, does see increased packet loss and latency. So it's only the PPPoE based "Internet" connection that is affected by the congestion.

The physical pipe to the nearest core node or WBC interconnect (21CN backhaul?), isn't saturated, but whatever logical pipe BT Retail uses for Infinity is... What could it be? Is it likely to be the SVLAN again, or something else?

And more importantly, is it something BT can easily fix?

[Edit] Just noticed AAISP say Denburn is fixed, but Plusnet say is it not http://community.plus.net/exchange-information/

Re: Congestion Isn't Just VM Only
 

Well, funny enough about 2am last night our connection went down and BT supposedly installed an additional 10G pipe for added capacity, no problems visible today.

Re: Congestion Isn't Just VM Only
 

Infinity 2 connection

https://www.cableforum.co.uk/images/...2014/04/14.png

HomeHub 5 stats

6. Data rate: 20000 / 79995
7. Maximum data rate: 37191 / 130099
8. Noise margin: 16.9 / 22.0
9. Line attenuation: 0.0 / 8.3
10. Signal attenuation: 0.0 / 8.3

not a clue what all that means though :D

Re: Congestion Isn't Just VM Only
 

It means that your connection is fine.

And with the correct upgrades your line could be capable of 200Mbps+