[mythtv-users] Way OT: High-speed Data Service Delivery

Jay Ashworth jra at baylink.com
Tue Jul 12 05:52:34 UTC 2011


----- Original Message -----
> From: "Jason Long" <jlong at jasonlong.com>

> On 7/11/11 7:35 PM, Jay Ashworth wrote:
> > Though, these days, it's almost never actually a T-3 bringing you
> > your DS-3/STS-1. It usually fiber.
> 
> That's not correct. A DS3 is delivered via copper coax.

Not quite.

A DS-3 is a *bit stream* (equivalent in speed, though not necessarily
in framing, to an STS-1) that has traditionally been delivered over dual
coaxes (a "T-3") to customer facilities, yes.

If you can get a LEC to deliver you a *newly installed* copper T-3
to you these days, my hat is off to you.  If they have to do all that
engineering and trenching anyway, I guarantee you they will be putting
fiber in the dirt, and the only thing that will be a physical copper
T-3 will be the 10 or 20 feet from their side of your room to yours...
assuming you cant take delivery on 100BaseT these days for some reason.

>           Sure, once your bits hit that fiber they travel close to the
> speed of light, but your DS3 signal still only allows you to transmit
> bits onto the wire at a line rate 44.54Mbps (after signaling
> overhead), so it's a moot that fiber is even involved.

Not if you're the one installing it, it's not.  I put in a copper T-3 and
all those repeaters, and that's *all* I can shove down it.  If I give
you fiber, even if the handoff from my mux to your gear is coax, my mux can
do a *lot* more stuff.  Looking from the carrier side, there, in case I
wasn't clear.

My last job, I took a 10baseT Ethernet handoff from Level3... and their
physical delivery to me came out of a mux with OC-12 SONET on the back of 
it -- 622Mbps to the building, to give me 10.

No, no one's installing T-3 *distribution* services anymore, so far as I 
know.

Cheers,
-- jra
-- 
Jay R. Ashworth                  Baylink                       jra at baylink.com
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates     http://baylink.pitas.com         2000 Land Rover DII
St Petersburg FL USA      http://photo.imageinc.us             +1 727 647 1274


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