Cable/DSL "shared" access myth (was Re: [TriLUG] Port 25 blocked)

[Ken Mink]

On May 18, 2004, at 3:48 PM, Jeremy Portzer wrote:

> On Tue, 2004-05-18 at 15:32, Stephen Hoffman wrote:
>>    I'm still feeling the service out, but so far I love it...The 
>> reason I
>> stayed with DSL was the dedicated bandwidth (I'll sacrifice speed for
>> consistancy).
>
> The idea that DSL has "dedicated" bandwidth is one of the biggest myths
> of broadband Internet.  Sure, the bandwidth is "dedicated" from the CO
> (Central Office) or DSLAM (DSL access module) for the "last mile" to
> your home or business.  But it's not dedicated from there upstream!
> You're still sharing bandwidth with your neighbors, and anyone else at
> at your ISP, where the ISP connects to the Internet backbone!  Plus,
> your DSL modem has significant bandwidth caps that negate how much of
> the backbone you can use anyway.
>
> A cable modem connection shares the cable with your immediate 
> neighbors;
> usually a very small number like 10-15 (maybe slightly more in
> apartments).  But this doesn't matter, because the capacity of the 
> cable
> modems is high (55 Mbit or something).  Your individual modem is 
> limited
> to a much smaller value (with TWC it's usually 3 Mbit down/384Kbit up).
> So you're never going to be in contention with your neighbors anyway!
>
> The fact is, cable modems offer much more bandwidth for the money
> (standard DSL in this area is often 1.5 down/128kbit up -- Cable is
> twice the download and three times the upload speed).  Cable is usually
> slightly less absolute cost than DSL ($41.95/mo. for Earthlink vs. 
> 49.95
> for full DSL service).  Sure, both cable and DSL can become congested
> during peak periods when the Internet *backbone*  -- the ISP's upstream
> connection -- becomes clogged.  But you should NEVER have any problem
> due to congestion in the "last mile" section, even though this is
> technically "shared" in cable access.  The shared access segment is
> simply not a factor in your connection's speed or utility!

Jeremy is right on with this. I have RR service and when I was having 
problems I spent a long afternoon trouble shooting with one of their 
network engineers. He was checking port configurations and such. We 
were talking about bandwidth and such. According to this guy, if they 
have a hub that goes over 40% usage, they resegement.

The last mile won't be your bottleneck. The download speeds I get from 
RR's nntp servers are insane, even during peak hours.

Ken
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