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back to article ISP condemns new BT backbone

Business ISP Andrews and Arnold has strongly criticised BT's new 21CN network backbone as unable to cope with current bandwidth demands. The small firm runs a network status blog for its customers, and this morning came out with some harsh words for BT. "It is quite clear to us that BT's 21CN network simply cannot cope with …

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Anonymous Coward

Packet shaping

is to blame here

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Anonymous Coward

Hmmm

you mean "traffic shaping" ?

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Troll

@r81miller

yep, you're right, that's exactly what I meant :)

I reckon the down votes are from BT drones

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Boffin

ADSL2 <> 21CN

21CN was not done to provide ADSL2. It just happens to have been sucked into the overall scope. The original 21CN premise could be achieved without even touching the DSLAMs.

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Stop

Except...

Shirley, part of 21CN was always (at a local level) to replace exchanges + DSLAMS with MSANs, so why not make sure the MSANs do ADSL2+ while you're at it?

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FAIL

Coincidence?

Wonderful timing. BT ran an event this morning entitled "BT WAN: Fit for Business" where they were selling the virtues of their 21CN backbone and the services they offer on top of it. AC because the lunch wasn't bad and the views from the top of the BT tower are amazing, so would be nice to be invited again :)

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Anonymous Coward

Forgive my stupidity

But how does 21cn tie in with the fibre roll out? Or does it not???

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It doesn't

(Directly). 21CN is switchover from the old PSTN to an IP based backbone.

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Boffin

Not in the slightest

21CN was originally about replacing half a dozen different legacy protocols (including ATM) in their core with IP. In other words BT would operate an exclusively IP based network. At face value there was no need for it to have any impact on xDSL. It has an impact on the backhaul and core but the local loop didn't need to change at all.

However in order to do this work they needed to replace the equipment in exchanges that performs the analogue to digital conversion for voice calls. For whatever reason they ended up buying in kit that can /also/ do the work of the ageing DSLAMs. This new kit goes by the name of MSAN (Multi Service Access Node). It also happens to support ADSL2+. In my opinion someone at BT saw a marketing opportunity and therefore decided to tout this as a benefit of 21CN.

In my view it's no such thing. It's a nice side effect of the new equipment.

Meanwhile to address A&A's complaint:21CN does cause BT to overhaul the backhaul and core network (basically the way that data gets to/from your exchange). They came up with what on the face of it are improvements on the old IPStream and DataStream service. In practice, as many of us expected, they are making what is known in technical circles as 'A right old bog 'ole of it'. Eventually the services might live up to their hype but right now BT appear to (using another technical term)' Not got a bloody clue'.

The real irony is that A&A are apparently getting a good ADSL2+ service out of Be (an LLU Operator) and I'm pretty sure that Be use BT almost exclusively for their backhaul.

So put another way:A company buys network capacity of BT is doing a better job of wholesaling its service than BT is itself managing.

Okay so BE isn't at every exchange but from what A&A are saying the problem is with the core and or ISP end rather than at exchanges.

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title

Fibre relies on 21cn, as it requires an IP backbone. It seems even more susceptible, as there's contention at the cabinet as well as the exchange.. during the football matches I was getting about 5% of sync speed.

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Fibre upgrade

I believe, however maybe wrong, the 21CN is the project name for the backbone upgrades roll out. They need to upgrade this to get the BTinfinty service which is fibre based to the cabitents on the street.

I may be wrong, BT really is the ministry of duff infomation.

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Actually no

FTTC does not have contention at the cabinet. The connection back to the exchange is 1:1 - the same is it for ADSL.

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@AndrueC

Rather brilliantly summarised, except:

"The real irony is that A&A are apparently getting a good ADSL2+ service out of Be (an LLU Operator) and I'm pretty sure that Be use BT almost exclusively for their backhaul"

Be don't use BT as far as I'm aware for backhaul, certainly not exclusively - the reason I know this is that when Paddington blew up, Be weren't affected.

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Fair enough

It was a long time ago that I heard that and it was before O2 took over. It's not something they'll ever confirm to me anyway :)

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FAIL

Must be a fault then

If there's plenty of capacity within BT, then what Andrews and Arnold are experiencing must be a BT fault.

Nice of BT to turn around and blame the ISP rather than investigate it first.

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Stop

ITYM...

Normal for BT to turn around and blame the ISP rather than investigate it first.

There, I fixed it for you.

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I don't understand...

Why are A&A commenting on this other than for PR reasons? Surely if, as an ISP, they are any good they will be using LLU in which case the state of BT's 21CN is a matter for BT's customers, not for them. I use Be and my broadband leaves BT at the exchange and hopefully never touches them again!

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Badgers

They are a customer?

And a small, technically savvy customer for a BT service that they're seeing problems with. If their customers are complaining it's reasonable to try and explain to them. LCP is part of the PPP protocol, so not something end users normally monitor but can troubleshoot problems with the BRAS/PPP servers. Those are controlled by BT, not A&A. LLU ISP's can and do experience the same problem, but they have more control over the DSLAM -> BRAS flows to manage it.

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This post has been deleted by its author

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Boffin

This is a title. A TITLE.

A&A use a variety of services. They also resell Be's wholesale LLU service.

> BT at the exchange and hopefully never touches them again!

Doubtful. Be's network was originally created using BT's BES/WES services. They may be using other suppliers right now but only a few LLUOs own any significant quantity of cable and almost all of them are reliant on BT to carry the data out of the exchange initially. It's just the way that it is. BT has so much fibre in the ground connecting so many places that building a network without using them is nigh-on impossible and often doesn't make financial sense.

When it comes to shifting /raw/ data from A to B BT is a one-stop shop and actually not that expensive. It's when you want them to help out with managing the data flow that things get a bit wobbly and expensive.

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AAISP do use LLU

AAISP wholesale Be's service as well. However, Be aren't at every exchange, so they also have to wholesale BT's product as well, in which case the state of BT's 21CN is a matter for AAISP because AAISP are BT's customer.

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Stop

When did they lay cable?

So be laid cable everywhere to send this data somewhere other than your exchange did they? Interesting.

Although it is more likely that LLU is Local Loop and not Backbone.

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Go Rev K!

A&A offer both.

The reason that A&A get involved in these sorts of activities is because they are considerably more competent than many others and they have a policy of openness with their customers, of which I am pleased to be one.

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@Tom 15

They do offer lines via Be. Some of us are not lucky enough to have an unbundled exchange though.

I'm sure most people's connectivity comes via BT, so I support them having a go at BT. And yes, I use them as my ISP.

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Anonymous Coward

Real LLU...

Not that easy, sure the LLU (might) terminate at your ISPs DSLAM at the local exchange, but guess who supplies the backhaul line from that DSLAM into the ISPs core network? Yes, it's very likely to be BT (who else has lines all over the country..)

So LLU is just a short detour really, most time your packets will still be travelling on a BT line. Now usually these would be leased lines supplied from within BT's SDH network, with guaranteed bandwidth and precise latencies.

Throw in 21CN and what have they replaced these leased lines with? Cheap but far more unpredictable Ethernet.

Now sure if you have lots of capacity this relative unpredictability is not a big issue, so these complaints might all just be positioning in advance of negotiations, but the issue is out there.

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@Tom 15

Either way it's still worth them pointing out when the incumbent monopoly telco's backbone is a sack of shit.

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Explanation

Just to make things a little clearer, Andrews and Arnold do sell LLU products, as well as BT, allowing them to offer their customers a choice. From the monitoring and analysis they have performed it is clearly an easy choice to take an LLU product. Key point they are trying to make is that BT say its fit for purpose, when they have impirical evidence to the contrary. They perform the same monitoring on the LLU lines and dont have the same problems, proving its a BT Network issue.

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Grenade

@tom 15

Yes all very well. But the state of LLU is such that you can't guarantee having the provider you want in your exchange. Ok there's CPW and Tiscali in many but who the hell wants to use them?

BT still has the lions share of DSL connectivity in the country.

I'd also add, as an A&A customer I can say that these guys wouldn't be complaining openly if they didn't have the facts straight and also hadn't been badgering BT for a long time. In fact if you read their blog post:

"We have been chasing BT for this for weeks now, and are getting nowhere. Hopefully this posting will prompt BT to make some formal response to their apparent capacity issues. Either admitting they can't cope, claiming the service is working as designed (i.e. designed not to cope) or if we are very lucky - giving a clear timescale for when it will be fixed."

These guys are also consummate professionals. They push BT hard to get faults fixed and faults that other ISP's would just give up on and happily lose your business to get away from.

Best DSL ISP I've ever had over the past 10 yrs, trust me, this isn't a PR stunt.

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FAIL

Because....

...unless all the customers that A&A want to gain have LLU'd exchanges, they have to use BT-supplied backhaul for some of their infrastructure.

Don't you think that if *all* exchanges had LLU that BT would have either a) no customers or b) much better value and better performing services?

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Stop

Oh Rly?

"any good" and "big enough to make a substantial investment in LLU" are not the same thing at all.

Carry on.

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No, apparently you don't

A&A aren't a massive ISP but since I switched to them I've had absolutely no problems with bandwidth and only one outage of a few hours that was BT's fault. My usage is pretty comprehensive: VoIP, VPN for business during the work day, frequent streaming audio & BBC iPlayer evenings and weekends - it works, plain & simple.

Prior to switching to A&A I'd made the mistake of assuming ADSL service, being ubiquitous, was now a undifferentiated commodity, bad mistake, far from it. Previous supplier, O2 (via BT IPstream), had become unusable with their traffic shaping &, obviously, massively over-subscribed Central pipes.

A&A comprehensively reports on service performance and charge for use graded by when you use it. - none of this "all you can eat" for a ridiculously low price that's typical of so many other retail & SME ISPs. They mix and match LLU with BT IPStream wholesale service on the basis of what's available but do remember that it's typically only exchanges serving large metropolitan areas where LLU is economical.

No disclosures necessary, simply a satisfied A&A customer of a company who provides the service they describe.

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RW
Flame

"More than adequate capacity" - whazzat?

More than adequate for _what_, pray tell? Giving enemas to elephants? [Sorry, dear Moderatrix, but that phrase burbled its way to the top of my mind without malice aforethought.]

That sure sounds like some kind of spin to me.

Wouldn't BT be further ahead in the long run if they actually tried to deliver plenty of bandwidth instead of trying to pack a hundred pounds of <whatever> into a fifty pound bag? Packet shaping is simply the response of a company that knows damned well their network isn't up to the job.

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Overselling.

It's a disease.

They don't give a toss about whether or not you get the speeds advertised, they care about you signing the contract.

And if Virgin have oversold their bandwidth then BT has probably done so several times over.

This is what you get when you a) live on an island and b) have a succession of supine, cretinous politicians who are so stupid that they don't know what questions to ask or what the answers mean when someone tells them what to ask.

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Some customers have no choice.

Tom 15: A&A DO offer LLU lines via Be but opnly cover about 70% of the population and there are plenty of areas where BT are the ONLY choice.

A&A are commenting on it as BT are refusing to accept that there is a problem and A&A are hoping that shining a little publicity on the issue will persuade BT to do their job properly and fix it. It's a strategy that has worked before.

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Happy

Up to 20Mbit/sec ?

My ADSL+ line speed is currently 22097 / 948 kbs up / down.

Then again, I don't use BT.

^ Smug grin.

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FAIL

A&A invented BT monitoring.

For those that don't know, A&A came up with a method of monitoring BT which is really really accurate.

All A&A broadband accounts are fully monitored every second. From the time I spent with A&A support techs (as a customer with one of their techs onsite for a few days) it was clear that BT engineers appreciated the A&A system, because it pinpointed system faults. A&A were even telling BT exactly what the problem was, even tho A&A didn't know what some of the BT codes were (i.e. when a fault was fixed, sometimes the fault report said (and I'm paraphrasing) A G10 whack fault on the Kapow Node, if at a later date their system detected the same symptoms from the monitoring, they would simply report it as a "G10 whack fault on the Kapow Node", which resulted in a "fault found. how the **** were you able to tell us that").

BT Management on the other hand didn't appreciate it, to the point of just outright saying "yes it's a fault, but why can't you wait until more people report it, we havent got time to fix all these fault reports you're raising".

FAIL cos BT don't like everyone knowing just how bad their 80's laid aluminium infrastructure is

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21CN just hope they make the deadline

Microsoft has leaned that calling products by their year of issue can cause problems when you end up shipping in the last months of the year.

I just hope that BT manage to ship 21CN in the 21st century.

Yes our local exchange was going to be upgraded in 2009, but alas we are still connected to 20CN.

I don't think A&A are doing this as a PR stunt, reading their status page you get an impression that the 21CN upgrade is constantly producing major BT outages, which BT consider acceptable collateral damage by changing the rules by which an ISP can report line latency faults.

BT appear to be taking the view that once they have performed an upgrade of an exchange that as long as everybody is still connected then "thats good enough for government work" even if new subscribers to 21CN may be worse off than being connected to 20CN.

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FAIL

"It'll be interesting to see if anyone else has criticism for 21CN"

Of course they do. This "21st Century" network of theirs doesn't even support IPv6!

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Boffin

You're confused.

21CN is about how BT move data around their network. This is different to the internet. Internet access is just another application the same as voice, ISDN, Ethernet and who knows what other services BT offers.

All of these are 'encoded' for want of a better word before being pushed around BT's network. Voice and ADSL for instance are carried using the ATM protocol (hence PPPoA that most people use to connect). As I understand it the problem BT has is that these applications don't all use the same underlying protocol and as a result their network layer is a bit of a mess.

The idea behind 21CN is to shift everything over to a single protocol - IP - which ought to simplify their network operations.

This does not mean the packets you send from your modem will suddenly be sent unaltered across BT's network. They will still be encoded it's just that the underlying protocol will change.

To be honest I only have a lay person's understanding of this stuff but a simpler way to look at it is to think of 'internet access in the UK'(*) as being a form of VPN that BT make available to people. The fact that their VPN doesn't currently support IPv6 is not the fault of 21CN(**). For all we know 21CN is using IPv6 but I think it unlikely. I can't see BT having enough nodes on their network to require the address space. What I don't know is what address range 21CN uses. Does it stick to 192.x or 10.x? There'd probably be no reason to. It's a private network (I bloody hope so, anyway, lol) so they can use any address range that takes their fancy.

(*)Although I imagine all countries do the same. I can't see any other way for it to work. You don't want your customers sending actual packets around your network.

(**)Very few UK ISPs do support IPv6. Ironically (but those in the know are not surprised) A&A are one of the very few ISPs that do.

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Boffin

But there again...

Hands up all those who are surprised...

[Tumbleweed]

No one? Thought not.

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Who cares about 21CN...

.... when the BT b'stards refuse to do anything about the appalling line I have to the BT exchange that even barfs and chokes with relentless regularity at 0.8Mbit/sec. They have point blank refused to run a 30 metre copper cable to a nearby FTTC cab so I can enjoy the 16Mbit/sec that my neighbours get.

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Happy

Or it could be money?

Sounds like BT are shifting the blame onto the ISP for choosing a low capacity price plan on 21CN.

Maybe they have?

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Go

"Why are A&A commenting on this other than for PR reasons? "

Possible reasons include: (a) because they know what they are talking about and have a history of being blunt when "defective by design" things inside BT affect the service to AAISP customers and prospective customers (b) because they have an alternative to BTwholesale's much overhyped much delayed 21CN, an alternative carrier with a proven network, and (more recently) a proven interconnect to AAISP.

"Surely if, as an ISP, they are any good they will be using LLU "

LLU on a widespread basis is uneconomic for all but the largest ISPs. There are some LLU wholesalers and one of them is the alternative of choice at AAISP (the one you already use, as it happens).

Other ISPs typically lack either the technical knowledge or if they have the technical knowledge they don't have the alternative carrier and so are frightened of speaking out (hello Rochdale can you hear me? And where are Metronet when you need them? Oh yeah, I forgot, BT own them now, and all that remains is the name. Hi Paresh, Hi Alex, etc, we miss you all)

It could of course be for PR reasons as well, and I hope it gets them lots.

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Not the same Tom

although I also have Be...

A&A are like the uber ISP on BT's network. Their packages aren't cheap, because they expect you to use it. They are technically proficient, and if they say it is so, it is so.

@Number 15 - some people have no choice but to use BT's network, in which case you get the best ISP you can, like A&A.

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WTF?

Looks poor from here!

Zen Internet, ADSL2+ 14Mbps Sync with exchange (1.3Km distant)... this lunchtime *very* sllllooooowwwwww and dropped packets:

root@cruella:~# traceroute dns.thorcom.net

traceroute to dns.thorcom.net (193.82.116.5), 30 hops max, 60 byte packets

1 router-zen.tubby.org (82.68.212.70) 1.520 ms 1.736 ms 2.336 ms

2 losubs.subs.dsl2.wh-man.zen.net.uk (62.3.87.147) 174.112 ms 174.494 ms *

3 * * ge-2-1-0-164.cr1.wh-man.zen.co.uk (62.3.87.165) 176.706 ms

4 * ge-3-0-0-0.cr2.th-lon.zen.net.uk (62.3.80.45) 182.866 ms *

5 * * linx-gw.ltn1.intl.telstra.net (195.66.224.14) 184.507 ms

6 154.32.3.142 (154.32.3.142) 185.234 ms * *

7 * * cr-1.LDN4.intl.telstra.net (154.32.3.241) 176.118 ms

8 154.32.9.17 (154.32.9.17) 176.559 ms * *

9 6.57.32.154.intl.telstra.net (154.32.57.6) 192.808 ms 210.686 ms 210.327 ms

10 ns0.thorcom.net (193.82.116.5) 194.420 ms 195.919 ms 199.638 ms

root@cruella:~# traceroute dns.thorcom.net

traceroute to dns.thorcom.net (193.82.116.5), 30 hops max, 60 byte packets

this afternoon things picked up again:

root@cruella:~# traceroute dns.thorcom.net

traceroute to dns.thorcom.net (193.82.116.5), 30 hops max, 60 byte packets

1 router-zen.tubby.org (82.68.212.70) 1.569 ms 1.775 ms 2.212 ms

2 losubs.subs.dsl2.wh-man.zen.net.uk (62.3.87.147) 27.572 ms 28.733 ms 29.719 ms

3 ge-2-1-0-164.cr1.wh-man.zen.co.uk (62.3.87.165) 30.191 ms 30.786 ms 31.428 ms

4 ge-3-0-0-0.cr2.th-lon.zen.net.uk (62.3.80.45) 38.553 ms 39.520 ms 40.255 ms

5 linx-gw.ltn1.intl.telstra.net (195.66.224.14) 41.477 ms 41.685 ms 42.703 ms

6 154.32.3.142 (154.32.3.142) 43.449 ms 42.513 ms 43.154 ms

7 cr-1.LDN4.intl.telstra.net (154.32.3.241) 44.731 ms 35.937 ms 35.922 ms

8 154.32.9.17 (154.32.9.17) 35.905 ms 36.494 ms 36.543 ms

9 6.57.32.154.intl.telstra.net (154.32.57.6) 46.054 ms 43.126 ms 49.067 ms

10 ns0.thorcom.net (193.82.116.5) 48.031 ms 46.817 ms 47.053 ms

root@cruella:~#

No hosts or users on my circuit.... you can clearly see that the first hop from my router to Zen (via BT 21CN) was rubish at lunchtime, yet my Cisco router showed "5 min input rate 31kbps, 10 packets per second" which is hardly stressful :-(

Mike

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FAIL

Andrews and Arnold are SHIT

I think this is an absolute lie. Why? Last Thursday, during the footie, we moved from an office with BT business broadband to our new one (just down the road, running of the same exchange) with A&A. Guess what? Fine on BT before the move, shit on A&A afterward.

Perhaps their "plentiful capacity" is why they're charging us £50 for 5GB per month, on a so-called business grade connection. And that's why we're changing as soon as business conditions permit. They are an absolute joke.

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Grenade

BT mole methinks

Suggest that you crawl back to your BT hole............

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FAIL

Thanks for proving the point for A&A

(Upfront - yes, I'm a customer)

The "plentiful capacity" that was failing was BT's network. A&A have been very public about the fact that a while back (can't remember exactly, but I think it was during the video peak before the world cup) their link to BT (the smallest pipe in their chain, I believe) was saturated. Although this was a "one off", they promptly arranged (as fast as they could) for this to be increased.

Since then, all of their pipes have been less than full - therefore any drop in throughput is the responsability of another part of the chain.

Also, the £50 for 5GB doesn't sound right - I think you might want to go and look at their pricing again, it doesn't match any of their tarriffs.

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Anonymous Coward

@Tom 15

Clearly you don't.

LLU isn't possible for many but does not deal with the issue with 21CN, or possible SNAFUs for FTTC that BT are heaving pimping.

AA already do offer LLU via Be tails, in to their network over L2TP.

M

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Big Brother

The problem was

that certain BT people thought they knew better than the suppliers when it came to optical networks design. Not BT optical designers of course (although there was some of that too), no it was the project managers and bean counters who did not care about future scalability.

Oh yes, and the application that was conspicuous by its absence in these considerations? Video!

Have to laugh really!

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