On 12/01/11 23:15, Lisi wrote:
So what would you have me call them to distinguish between whatever goes over LLU and what one can get on BT lines in a non-updated exchange? (I.e. one with a maximum ADSL speed of up to 8MB.) The speeds are completely different.
Firstly, let me state that I am not an expert in telecoms, I'm only regurgitating what I think I understand to be the case. LLU has got nothing to do with ADSL per se, it is an acronym for Local Loop Unbundling. This is a regulatory thing, best read up on it on Wikipedia [1] to properly understand the nerdy bits behind it. Other telecoms companies here that has LLU arrangements include TalkTalk, Tiscali and others. Most companies however simply re-sell BT Wholesale products at cheaper rates than BT's retail pricing.
What you might be referring to from a speed perspective are the different ADSL standards in use today. "ADSL Max" is a service and standard developed by BT (I don't know of any other country that has it), and it is re-sold by a lot of smaller ADSL service providers. ADSL Max typically offers speeds of 8Mb/s downstream, and 448Kb/s upstream. The new kid on the block is "ITU G.992.5", better known as ADSL2+. This have downstream speeds of currently up to 24Mb/s and upstream speeds of 1Mb/s. I'm not sure how prevalent ADSL2+ is, since it is quite new (it was only introduced in my local exchange less that 12 months ago). From what I can suss out, ADSL2+ providers typically have their own LLU arrangements, meaning that they are in full control of that last little bit of kit between the local exchange and your phone socket. Please don't take this as "telecoms gospel", it is quite possible that I don't know what the heck I'm talking about! ;-) I find the industry to be a rather complex beast.
In short: Where ADSL is concerned, ADSL2+ is the way to go. There are other connectivity options around - cable is interesting (speeds of up to 50Mb/s downstream), but we only have Virgin Media offering it as far as I know. Optical fibre seems to be making an entry into the consumer market, which is about time (places like Singapore, Hong Kong and Japan had it for years). Fibre optic speeds can easily go into the gigabit range. It is also fully synchronous in terms of speeds (same speeds upstream and downstream), since it is treated in the same way as normal ethernet. Both BT and Virgin have fibre offerings, still rather pricey at the moment, but certainly attainable if you really want it.
Links: [1] LLU definition: http://en.wikipedia.org/wiki/Local-loop_unbundling -- Regards, Jan Henkins -- Please post to: [email protected] Web Interface: https://mailman.lug.org.uk/mailman/listinfo/hampshire LUG URL: http://www.hantslug.org.uk --------------------------------------------------------------
