Paul Coxwell wrote:
> Off on a tangent somewhat, but is there any sort of numbering system
> applied to these modern ID numbers or is it more or less random
> allocation?
It's more or less random, and depends on the particular carrier's
prefernce for numebring schemes. For example, MCI/Worldcom has a
different numbering schme for its major switches than AT&T or Sprint.
> I'm familiar with the old-style IDs such as "914-1" for White Plains
> etc., but I've never been able to figure out how the current system is
> supposed to work.
It doesn't work, really, and is actually becoming less and less
relevant as the network topology flattens. The New Orleans 4ESS is
probably among the last of its breed, and I remember hearing that AT&T
removed a lot fo them from service long ago as they shifted towards a
decentralized network.
> For example, dialing into the NANP from the U.K. using an unallocated
> prefix within a valid area code often results in a "Your call cannot
> be completed as dialed" recording with an ID of "two" followed by two
> letters, e.g. 2BM. Are these class 2 tandem offices?
No, those are MCI offices, and their equivalent of class 4 switches.
(MCIWorldcom uses/used the NAA labeling system for their class 4
switches, i.e. "2BM" "2CU" "2CX" etc.) MCI is probably the last major
carrier to have a hierarchical structure in place, as it's widely known
that during the big telecom bubble that they helped create and then
burst, they were too busy cooking their books to actually invest in
restructuring and upgrading their network, and instead merely spent
only the money they needed to keep it running at a semi-decent level.
That practice continues to this day, pending the buyout of MCI by
Verizon, at which time it becomes Verizon's headache.
> Does the network even still use the same class designations as in
> the past?
Only in vestigial references. The Number 5 ESS is still around and
its reference is still used when operated as a class 5 end office, but
then you'll find lots of 5ESS (the model number, but not acting as the
class) performing tasks that resemble what a class 4 switch would do.
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Isaiah Beard (sacredpoet@sacredpoet.com)