ADSL2+ on NTL phone lines? [Archive]

Escapee

25-03-2005, 09:15

Has anybody read this article on the reg?

http://www.theregister.co.uk/2005/03/22/ntl_adsl2/

I mentioned this as a possibility in another thread but they said it wouldn't happen! :D

I bumped into a thread about this on one of my rare trips onto the Digitalspy site last night.

The thread is covering this topic, and as they are discussing there it seems a strange choice. VOD is better suited to this sort of technology, an individual pair of wires to each house is the only way to go with it. (FTTH) The bandwidth is re-usable to every single customer, unlike the HFC system where its main task is broadcast.

I expect rolling out VOD on ADSL would be a lot more costly than piggy backing it on the HFC network, both technologies have their plus and minus points.

HFC

Broadcast with lots of bandwidth efficiency available to all customers at a reasonable cost, but not that good for targetted services like full VOD because the frequency allocations can only be used again if the network is spilt, allowing that bandwidth to be ised again elsewhere. VOD cheaper to implement on this service but never likely to be the long term solution.

ADSL-2

large amount of bandwidth re-usable ie: dedicated to each cable feeding the customer. This technology is a step towards FTTH and will probably be a stepping stone for the future network build, service is more costly to implement initially because unlike HFC its difficult to install equipment to cover a large area, and then split the network and upgrade equipment as customers take up the service.

I saw talk about using the ADSL-2 service for off-net customers, I wonder how ntl are going to achieve this by relying on a BT network with much longer drops to the customer. I guess it will end up being a 2 tier service, where on-net customers will get better services than off-net.

I am an avid supporter of the HFC networks and the job its very suitable for carrying out, but HFC is not the right technology for VOD. The right technology will involve sending bandwidth down a single cable targetted to an individual customer, FTTH is the best solution, ADSL-2 goes a long way towards meeting the criteria, but HFC is a poor long long term solution.

BBKing

25-03-2005, 09:25

I think you're partly right, Kevin, but your objections to VOD over HFC apply doubly so to satellite and terrestrial broadcasting (no splits and no return path *at all*). ADSL 2+ (and no doubt follow ons with even higher bandwidth) is still futureware in many ways, and obviously a large-scale roll out with thousands of people viewing VOD events in an area has colossal demands on the back-end kit (in a way, the protocol and the kit in the home are the easy bit).

So VOD over HFC is about the best we're going to get in the near future, but it's not going to supplant conventional broadcasting any time soon. After all, splitting the network down, if taken to its logical conclusion results in each house having its own feed back to a central point, which is effectively a copper pair or FTTH.