[mikester]

Up until recently my career has been in the Cable industry - specifically Cable modems in Southern California.

Let me tell you what I know briefly.

The arguement that DSL makes is not false; the cable medium is a "shared" medium much like Ethernet is "shared."

Traffic these days is not sniffable, which means that your neighbor can't see what you're doing but it is still shared.

What makes their arguement false is capacity planning that cable providers do typically makes it such that you'd never know you were on a shared medium. To be honest - unless you're on a point to point network (which even DSL isn't) you're ALWAYS on a shared medium. Dedicated circuits are expensive. The difference between cable and DSL in that is that DSL gives you some separation to their CO - then you're shared. That's physical separation but in a network diagram showing the logical network it's really no separation and it gives you zero increase in bandwidth and contention if the CO is oversubscribed (which is a term invented by the telecom industry - they do it as a rule).

Oversubscription was an idea started back in the modem based internet days. For example - you could have 1000 customers served by 700 modems. The chances that all 1000 customers would be calling at the same time was slim - but with capacity planning you could add modems as your subscriber base expanded yet still have less modems than subscribers. Far far less in fact, busy signals became a marketing ploy back then if you recall; "We have more modems!" or "No more busy signals!"

That's what DSL tried to put Cable down with - something they themselves do as a rule.

Not saying Cable companies don't over subscribe as well - they do, make no mistake they do. But in their environment with the newest deployments almost all doing VoIP they have very thin margins of error. VoIP is very sensitive to latency and congestion on networks and call quality will degrade extremely quickly if they exhist. So to combat that the over subscription rates have been drastically reduced which makes for a more robust and available network (the goal in fact).

Cable is not going to last sadly as Fiber to the home is the reality and everyone knows it. Fiber has extremely high possiblities of speed AND can carrier more independant data in different colors of light than DSL or Cable can do by changing frequency or modulation (which is how they carry more data). With Fiber you can separate the colors of light into different and distinct data pathways and while one could be completely congested (say the data line) the other line could be completely uncongested (say the voice line). At the moment these technologies are quite costly but in the next decade we'll refer to cable modems the way we refer to dial up modems.

Where DSL suffers the most I believe is in the telco mentality and the telco pricing that mentality fosters. Telcos sell tiered services (some cable companies do as well but I won't get too much into that). The CONsumer grade product you get in your home typically sucks by design. You can almost always buy a higher tier and get faster speeds but you'll also have a much lighter wallet.

Cable companies are up until recently "best effort services" companies. So they try and always have tried to give the best bang for the buck; recently Time Warner upgraded eveyone carte blanche because they could. They built the network out better and so they could and did.

If you have questions regarding cable - I'll be happy to answer them. I don't work for the Cable Co any more so I have no vested interest. Cables not really "better" it's just better done because it has to be to support all of the services. Data, Video, Voice, all high demand services.