As to whether Comtralis's claim to be "number one" is right or wrong, is up for debate, of course!
:-)
As to the performance of broadband, it's an area I'm happy to admit I'm no expert in. Nor, I think, do many people understand the way it works.
Yes, I'm pretty sure that
/m4 is right, and Zen would have to have bandwidth enough in their own network to cover all their customers logging in at full speed simultaneously. That can happen!
What is less clear, is that it will happen as a rule, any more than on any other broadband network. Here's how I understand it (correct me if I have it badly wrong!)
1) BT provides a link from you, the ADSL customer, to its exchange. That goes into a DSLAM, the access module that takes your data and feeds it back into the network.
2) The Internet connection from the DSLAM is, for our purposes, unmeasurable unless we have access to BT's ATM network logs. It is assumed to be "sufficient" and BT has promised to ensure that it is.
3) BT routes your data link from its DSLAM to your ISP - say, Zen. When it gets to Zen, Zen has to be able to accept the data at the rate guaranteed by its contract with you, and it has to be able to feed it back at contract rate, too. If it has five customers with a one megabit service, it has to be able to cope with five megabits in its own network and forward it on to the next hop.
4) However, the link into the DSLAM is shared. Business lines are (typically) shared with 19 other users; home lines with 49 other users. There are also 7:1 contention ratios available.
5) In these early days for broadband, most people don't use their broadband most of the time. But already, there are starting to be issues. Some stream music at 48K for hours at a time; they'd rate as "heavy" data users. You can work out that this uses about 10% of your share of the DSLAM's capacity; that means that if ten of you are using it for this purpose, you've used up all your group's download capacity. There are, however, 50 of you on home, and 20 of you on the typical business contention group...
To me, it means that if you have
about a megabit per second, and you share it with 20 people, then ordinary Web access is going to work quite well. But if several of you start using big chunks of bandwidth continuously, it falls apart.
The advantage of the Mesh approach is that all traffic inside the Mesh is free. It isn't contended at all, except for the mesh overhead, which is small; the more nodes you have, the more bandwidth you have between members of the mesh.
Thoughts?
