SONET Interconnect (was RE: MCI)

According to Paul Ferguson:

>Currently, the only way of doing this is the "traditional way" of using
>SONET add-drop muxes to get you up to higher rates. You mux the STS-3c into
>an STS-12 and then mux the 12's into a STS-48. This is what we are doing
>in ATDNet which is a ATM OC-48 bidirectional line-switched ring for ARPA
and DoD.
>As per our previous discussion, the trend seems to be putting the switching
>and transport functions in one box so that you may be able to buy an
>ATM switch that also does SONET protection switching.

I fail understand, however, why ATM over SONET is desirable when there is
such a loss to overhead, especially when viable alternatives may exist to
get more bang-for-the-buck.

Perhaps someone could enlighten me on this particular datapoint?

Several of our clients seriously consider
ATM/SONET the best way to go because they feel that a switched
technology like ATM is the best single technology (currently)
to offer them high speed and support for multiple applications (like
video and voice, as well as data). They are not just sending around
200-byte IP packets. Furthermore, the ability to get
quality of service support and guarantees is important them. They don't
think that RSVP, when it comes, will be enough. Finally,
to them, the economics makes sense. They understand the limitations
(i.e. overheads) and believe that they are acceptable.

If viable alternatives exist that are cheaper and better for your
applications, you should use them. All I'm saying is that to lots of
other people, ATM/SONET is just as viable.