Phasing out of telco TDM Backbones (was: Phasing out of copper)

Jay Ashworth jra at
Sun Nov 30 05:59:58 UTC 2014

----- Original Message -----
> From: "Nathan Anderson" <nathana at>

kbones (was: Phasing out of copper)
> On Saturday, November 29, 2014 9:10 PM, Jay Ashworth <> wrote:
> > But let us not conflate being ok with telcos replacing analog copper
> > last-mile with being ok with telcos replacing PCM with VoIP,
> > especially
> > in trunking applications, ... [snip]
> Let's also not conflate audio codecs with L2. "PCM" and "VoIP" are not
> mutually-exclusive things by any stretch.

Oh, sure.  But my point is this:

How many Erlangs can you fit through that clear-channel T-3?

There's man-centuries of engineering in the design of the TDM backbone,
and the people making the decisions about abandoning that design weren't
even alive, in some cases, when that work was done, and don't know what
"Notes On The Networks" is.

-- jr 'I can lay hands on my copy in 60 seconds' a
Jay R. Ashworth                  Baylink                       jra at
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates          2000 Land Rover DII
St Petersburg FL USA      BCP38: Ask For It By Name!           +1 727 647 1274

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