LLU
 

What does everyone think of these LLU plans. I personally don't think they are a very good idea as I think there is going to be loads of service problems and as NTL would not be allowed to change things as they can with their own network. They will take months to get sorted. In the proposal they have released they are talking about services but I don't think BT's network is of a high enough standard to do them any time soon. There is equitment (line cards, etc) in BT exchanges almost 50 years old.

I think it would be better to invest this money in new builds (where there is high demand) and upgrading the rest of the network to support digital.

Re: LLU
 

*Moved to Broadband Discussion forum*

Re: LLU
 

Why? It's nothing relatively to do with broadband its to do with them offering all services over LLU.

Re: LLU
 

LLU is as much about telephony as it is internet. :)

Re: LLU
 

And Television too! ntl's plans for LLU include triple-play services.

Re: LLU
 

That is my point. Why was my topic moved from general?

Re: LLU
 

calm down!

I cant see why not experiment with LLU but arent they going where others have tried and failed due to BT being obstructive and the costs being very high. I recon it's just something to impress the bond/share holders and make it look like NTL are forward looking etc.

Re: LLU
 

There's also the point that you wouldn't get much new build for the price of LLUing the whole country, which obviously gives you greater reach. Remember the only BT infrastructure used in LLU is the twisted pair and the frame at the exchange, all of which is fairly passive and well run-in. I've certainly had no line problems at the two houses I've had DSL at.

It's not a piece of cake, but it's much the most efficient way of extending network coverage.

Re: LLU
 

This will obviously lead to a two-tier system with different services/products for on-net and off-net customers.

Supplying service to remote business customers always used to be a problem for ntl when there was a fault, BT will still be obstructive and I see no way around that problem.

I think it's a good idea, but in practice I just dont think it will be as good as some expect.

Re: LLU
 

Why obviously? There are technical differences between DSL and cable that mean things operate in very different ways on very different kit, but the high-level services are much the same, surely?

BT can be obstructive only as far as fixing the twisted pair to the customer, which is the least likely bit to go wrong, anyway. After that it's ntl's stuff to fix, thankfully*. Actually unbundling the customer could be another sticking point, as OFCOM want to ramp up the rate of unbundling, so BT could turn round and say 'we haven't got the staff'. This would get very short shrift, though.

*Yes, insert your own joke here, but I'd far rather work within ntl's fault management procedures than have to go to a completely separate company, we had enough of that with C&W a few years back.

Re: LLU
 

LOL, I don't think so. There was no such thing as line cards 50 years ago.

BT is now all digital and the oldest System X & System Y exchanges are less than 20 years old.

Re: LLU
 

Yes but they are finding it difficult providing more than 1mbit at around 4km through DSL. I can not see TV, etc working well over the twisted pair using video over DSL I assume.

Re: LLU
 

Wrong wording. When your twisted pair first comes into the exchange. Some exchanges have very old MDF's.

Re: LLU
 

Well it's because of the technical differences that I was making the comment, the twisted pair will be the big problem as far as I am concerned.

Yes I agree, the customer could have Internet at broadband, he could have digital TV. What if he wanted both, what if he wanted broadband, digital TV and a second set-top for recording?

I know you probably think I'm just being awkward or anti-ntl with my comment, but that twisted pair will make a big difference to the service on offer to a BT line customer compared to a HFC fed ntl customer.

Yes, BT could install a second line for these customers at ntl's request, but I wonder how smoothly this will happen when no spare lines are available!

It all boils down to the same as you say about ntl relying on cwc, I dont think it matters where the dividing line is drawn because the end result will never run as smoothly as it will on a system fully owned by one provider.

Thats all in my own worthless opinion though. :rolleyes:
(not aimed at you BBKing) ;)

Re: LLU
 

I don't think you can get Digital TV over the pairs like you can with NTL at the moment. I think what they have to do is provide the TV over the DSL.

Re: LLU
 

\

Precisely, thats my point.

Technically difficult to provide all services simultaneously over one pair of cable in DSL format as it would distance dependant on the bandwidth available etc.

The Digital TV would be more of a VOD type service because of the bandwidth constraints.

Re: LLU
 

I can't see it happening :(

Re: LLU
 

Going back 10 or 12 years when you only had dialup and your phone bills were like the national debt you wouldn't imagine that we could have services as fast and as cheap as they are today. :)

Re: LLU
 

Why would a 50 year old MDF make any difference ?

Re: LLU
 

Yes, but we are not really talking about a forward step here!

Offering Digital TV, Broadband etc over BT's network by LLU is a technically inferior delivery method to the HFC network ntl has in place on it's own network.

Broadcast is the big problem, HFC is disliked by all the Internety/data type people because it involves RF and fibre, they dont understand it to any degree. However it is currently an unbeatable medium for delivering TV/Entertainment type services. No matter what you offer down a twisted pair it's a compromise when compared to ntl's own HFC network.

There are parts of BT's network falling to pieces, just look at the mess when you see a BT cabinet open. This is exactly what happens when a company sits back, stops all maintenance that is seen as unnecessary and engineers are encouraged to concentrate 100% on speed with little regard to quality.

Roll the clocks forward about 10 years and ntl's networks will be in a very bad state if the current management trend is allowed to continue!
(Sorry I have diversified there a bit)

My personal view, is there is no way LLU services down an old twisted pair are going to be as good for a customer when compared to a HFC network.

Re: LLU
 

You are all making the mistake of assuming that ntl would merely duplicate what BT/Homechoice do - they're not, that's 1990s technology they're locked into due to the massive investment in DSL rollout.

Same applies to ntl's HFC - if you were putting in a cable network now you'd make sure it was segmented to future data levels and put DOCSIS 2 compliant kit throughout, not a mix of DAVIC, DOCSIS 1 and EuroDOCSIS 1. If you're putting a DSL network in you'd use the comparable modern DSL standards, which are in use in other countries (the ones brought up on here as 'why can't we have that here'?).

I've no idea whether it will work, but I can definitely see the point - HFC is indeed an excellent way to deliver services (not as good as fibre, but an affordable first step).

Re: LLU
 

I am purely looking at it from the technical angle, twisted pair DSL = very good for Intenet and VOD type service.

Twisted pair limited bandwidth not good for broadcast medium, both I admit are limited when compared to FTTH. Most of the FTTH trials in the past used RF over fibre like HFC anyway, I expect there could of been some later trials using pure data down fibres but I guess cost cutting by vendors due to decreased demand from operators has meant a lot of this trial work has stopped.

I think we will have HFC for many years to come on the existing networks, I'm not even sure if FTTH is cost effective for new build yet?

I would assume that ntl would package their product different to BT/Homechoice or Yes TV, but I can only see things altering if we look at TV as a VOD type service.

Re: LLU
 

I think that you are concentrating too much on what was possible in the past and the technology used in the past and not taking into account what may be being developed now or in the near future that you probably know nothing about.

Re: LLU
 

Because the whole provisioning of BT lines is very dated compared with NTL. I have worked in the BT exchanges and most of them are cack with not enough room to put the stuff in ntl would need to provide such services. It all comes down to space is the limiting factor and when all these compaies jump on the LLU bandwagon.

Re: LLU
 

It has very little to do with the past, and I do try to keep up with technology I am well aware that speeds can be increased, and will be increased all the time.

If you take all the broadcast channels on ntl's current line up and add all the bandwidth together, do you ever think it will fit down a twisted pair designed for audio?

The bottom line to the whole discussion is that ancient twisted pair!

PS: It only takes a couple of hundred watts from my HF amateur radio transmitter to stop my ADSL downloading dead at my house, this just shows how poor the balance is at those sort of frequencies with BT's old twisted pair network. I often wonder if it has the same affect to other ADSL users in the street when I'm using full power.

If it does I guess they just blame the slow provider. :D

Re: LLU
 

Doesn't TV-over-DSL just send one channel at a time? That's probably a maximum of 3Mbit/sec, and probably less. All but the shortest runs of phone wire should be able to cope with that.

Re: LLU
 

But one channel will and that's all that a set top box can display at one time so there's actually no benefit from having hundreds of channels available to it via coax.

Re: LLU
 

Did you believe 15 years ago that speeds of 8Mbs could fit down that ancient twisted pair?

Looking at it another way, that twisted pair only has to carry two or three TV channels at the most and in many cases only one. What is at the other end of it is really what matters.

When you look at technological advances you have to think how fast they are coming about and todays impossibility is tomorrows taken for granted.

If you look at what we have today, most of the technology would have been classed as a pipe dream when I was a child.

Re: LLU
 

One of my earlier posts in this thread said that, I made a comment about it being suitable for VOD or if we change our view and considered it a VOD type service instead of broadcast.

Yes, the set top box can only display one channel at a time, but currently the customer has facility in many cases to watch one channel, record one of the off air bypass channels and surf the net at the same time. This will be impossible with the current bandwidth available down DSL.

I understand (from BBKing) that improvements have been made in bandwidth available over ADSL, and I assume it could now be possible to have 2 or 3 different services running on the available bandwidth.
I assume much of this has been made possible by clever Error correction, Software and protocol changes to overcome the shortcomings of the twisted pair.

ADSL is a method of making a silk purse out of a sows ear, there will only be so far they can go with software changes/fudges until they need to start upgrading the distribution network.

Time will only tell if higher bandwidth services over BT's ancient twisted pair network will be relaible and just as importantly available to the mass majority of householders. Even some people within the required distance of an ADSL enabled BT exchange are still not able to get ADSL service!

Re: LLU
 

IGMP

You're thinking of this too much like a CATV network, rather than what it is, video over IP using ADSL as a low level transport stream. What's a webcast / multicast if it isn't accessing a broadcast on demand? Multiple streams may also be possible, depending on bandwidth and encoding requirements. Currently it's not possible to record a cable channel and watch another due to tuner restrictions, no great change here.

So long as the line can take the bandwidth for one stream all channels delivered to the exchange / DSLAM can be provided on demand on a per port basis, in contrast to VoD where an individual transport stream will be supplied.

For the interested, I'm not giving away anything interesting, this is the only way this sytem could work, and is how HomeChoice manage to offer VoD and 'broadcast' TV over their network.

Re: LLU
 

Thats what I was getting at, the service will be different to the one currently offered to on-net customers.

Unless the latest technology/service allows the customer to watch one TV channel and record either an off-air one, or one from a second box whilst surfing the net it will be a lower level of service. (Even if a customer doesn't have by-pass facility they can currently subscribe to a second box)

Perhaps I didn't put it over very well, but what I was getting at is it is more of a low cost VOD service for broadcast channels than an alternative to ntl CATV or SKY.

Re: LLU
 

Cable & wireless are also getting into LLU big time with their purchase of Bulldog.
They claim 4 Mb speeds over DSL!!
Also the age of line equipment at the exchange is irrelevant because the line is intercepted at the MDF and connected to a DSLAM and to the exchange line card. The telephony path is transparent to DSL. As someone has already pointed out, the oldest exchanges are about 20 years old. (Ntl's oldest are about 10 years old but without the BT advantage of regular software & hardware upgrades, costs too much money you know?)
NTL are committing a lot of resources to this project. :dunce:

Re: LLU
 

The point I was trying to make is the ancient twisted pair, that was designed for audio frequencies. ADSL down an old audio cable with many repaired joints is always going to be a compromise when compared to a good quality coax cable.

Looking inside a BT cabinet around my area a while ago, when a BT engineer was working on it makes me wonder how it ever works. The twisted pair certainly needs to be made off correctly to provide correct balance and good rejection to ingress/egress, as you are probably aware (sorry if I appear to be pushing something you already know) rejection on twisted pair relies on the twist to cancel out any out of balance signal being picked up by the cable. It provides a push-push effect that is cancelled out at the twist, as both signals appear in phase and cancel one another out.

I have some past knowledge of Rediffusions old HF CATV systems using twisted pair, we also carried out some digital TV tests on one system but had big problems with group delay and balance of the twisted pair network.

The local BT box was certainly a shambles for efficiency in this area.