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.