Joseph Gibbs wrote:
There are several reasons why you get that speed: 1) Your line quality might suck. 2) A sucky DSLAM (Conklin) 3) Congestion from your DSLAM to the ISP 4) Congestion from the ISP to your destination site.
LLU fixes the first 2 trivially, and makes 3 avoidable.
A correction to this, it fixes the second trivally. It actually has the potential to make the first point much much worse due to less co-ordination between the users of the copper
Excuse my ignorance, but is a DSLAM and the 'exhange' in fact one in the same (or in the same 'box')?
DSLAMs live (traditionally) in Exchanges.
Also (perhaps this warrants a new topic), Telecom won't give us or our ISP any indication of when our local exhange will be upgraded. Any ideas on how I can hassle Telecom to get that done faster? Our ISP says that they have many people with the same problem, and that no one knows when any particular exhange may be upgraded, just that there's a list of exchanges that need it.
Also, out of interest, what sort of area (in terms of size or amount of lines) does any one particular exchange usually service?
As a rough guide. A typical DSLAM terminates roughly 2k DSL connections and I believe has a 155Mbps upstream link to a RAN. A DSLAM of this type takes up about half a rack (20-30U) and generates lots of power and heat. In cases like Craig mentioned where fibre has been pushed out closer to the home and the DSLAM lives in a cabinet small mini-DSLAM devices called Conklins are used. These have 8 ports (although they are stackable up to about 48 ports I believe). Conklins only have capacity for an 4Mbps upstream link. Further complicating things DSLAMs can be subtended of each other (Conklins are always subtended to a bigger DSLAM) causing futher sharing of the available bandwidth. Cheers -- Matt Brown matt(a)mattb.net.nz Mob +64 21 611 544 www.mattb.net.nz