[10866] in Commercialization & Privatization of the Internet
Re: Two-way Internet service from Continental Cable?
daemon@ATHENA.MIT.EDU (Dave Crocker)
Sat Mar 12 23:53:37 1994
Date: Sat, 12 Mar 1994 16:40:08 -0800
To: "Martin L. Schoffstall" <marty@psilink.com>
From: dcrocker@mordor.stanford.edu (Dave Crocker)
Cc: com-priv@psi.com, fellows@farnsworth.mit.edu
At 6:02 PM 3/11/94 +0000, Martin L. Schoffstall wrote:
>A TV channel is 6Mhz.
>
>In Cambridge we are using two.
Does this mean one upstream and one down, effectively creating a 6Mbps (or
thereabouts?) single ethernet?
How are you able to get any sort of reasonable contention mediation for the
upstream (customer-to-headend) in the absence of customer equipment being
able to see each other (i.e., no carrier sense and no collision detect?) or
are you, in fact, able to get full CSMA-CD functionality? If so. Wow.
And how?
Also, how many customers are going to be sharing these two channels? A
not-so-minor issue with community data cable access is the level of
sharing. From your analysis of the "peak" capacity, I couldn't tell how
many customers that meant would be sharing the local wire, or how many
would be sharing the capacity of the up-link concentrator
(super-neighborhood) channels.
Thanks.
Dave
