Some More Info on CLLI Code Assignments/Formats/Structures
Mark J Cuccia
"complete" list of (current) rules/etc. on CLLI code assignments and
structure ...
Jay R. Ashworth wrote:
> Can you clarify how it might be that *every switch in my county* has a
> "building" of "XA":
> SGBHFLXA39H
> NGBHFLXA39H
> BAYUFLXA54F
In the "old" days (and most CLLIs or at least top-level CLLIs have a
great deal of "legacy" aspects about them), the 2-character "building"
code beginning with 'X' was "reserved" for non-Bell telcos in US
jurisdictions, and non-TCTS-member telcos in Canada.
The "building code" part could be 2-alphas or 2-numerics, but *NOT* a
mixed alpha-num or num-alpha.
*NOT* all of the independent telcos necessarily had building codes
starting off with 'X', but *MOST* did use them.
And the "popular convention" was to have the first (or "main")
building in that city (town, location) served by an independent telco
was to have 'XA', and then 'XB', etc. This wasn't always consistant
neither where 'X' was used.
This is now only "legacy", because the only "rule" that (still)
applies to the encoding of "buildings" in CLLIs is that it be
2-alphas, OR 2-numerics, but *NOT* a mixed alpha-num nor
num-alpha. (THAT is reserved for other types of network elements not
inside a building, and it would be a complete 5-character form to fill
out the remainder of the eleven character CLLI, as
alpha-num-num-num-num-num, or num-alpha-alpha-alpha-alpha.
> I thought it was sort of neat how GTE coded the NXX into the CLLI:
> it's the first two digits of the prime prefix on the switch, and
> whether it serves Half the prefixes in that block, or Full.
Of course, that was "nice" because in the "old" days, it indicated the
*range* of prefixes, usually in SxS switching offices. However, as
that SXS switch was replaced, many telcos (incluing BOCs, such as some
places of Southern/South Central Bell), retained that trailing
three-characters of num-num-alpha (with some restrictions on what that
final alpha could be, in this case of encoding a CLLI for a local
central office).
Some CLLIs used the actual three-numerics of the (first) c.o.code
served by that c.o.switch. That's "nice" for small towns or switches
in rural areas that will never have more than a single c.o.code.
But when things become portable more-and-more, this format of
num-num-num or num-num-alpha, based on the NXX c.o.code, will become
meaningless, and even *misleading*!
A better, and more *PREFERRED* method of encoding CLLIs for *local*
c.o.switches, is "tecnology" or "service" based, i.e...
-SG(char) for Step-by-Step (Selector Group)
-MG(char) for Crossbar (Marker Group)
-CG(char) for non-digital ESS (Control Group)
-DS(char) for Digital ESS (Digital Switch)
-RS(char) for Remote Switch
-RL(char) for Remote Line (card)
-PS(char) for Packet Switch
-RP(char) for Remote Packet (switch)
-CM(char) for Cellular/Mobile (switch)
-VS(char) for Video Switch
-OS(char) for Optical Switch
-OL(char) for Optical Line (card)
etc.
And there are other formats of the "trailing three characters" to
identify operator boards/positions, call distributors, toll or tandem
switches, SS7 signaling nodes, etc ...
Mark J. Cuccia
mcuccia (at) tulane (dot) edu
New Orleans LA USA
AND, since this is a post about CLLIs, and I've had requests from time
to time about my some things in my various old sig-lines, here it
goes!
NWORLASKDS0 (BellSouth #5ESS Cl.5 Local "Seabrook" 504-24x-)
NWORLAIYCMx (BellSouth-Mobility MTSO NOL ?Ericsson Cellular -CM3?)
NWORLAMT01T (BellSouth DMS-100 "Metairie" Tndm; Cellular routes thru)
NWORLAMA0GT (BellSouth DMS-100/200 inTRA-LATA/fg.B-C-D Tndm "Main" 504+)
NWORLAMA20T (BellSouth DMS-200 TOPS:inLATA Opr.Svc.Tndm "Main" 504+053+)
NWORLAMA04T (AT&T #4ESS Class-2 Toll 060-T / 504-2T "Main" 504+)
JCSNMSPS06T (AT&T #5ESS OSPS:Operator-Services-Tandem 601-0T 601+121)
JCSNMSPS14T (AT&T #4ESS Class-3 Toll 040-T / 601-2T; OSPS routes thru)
NWORLAELH01 (PBX NEC-2400 504: 862-3/8xxx 865-4/5/6xxx 314-2,7xxx)
NWORLACADS0 (BellSo.DMS-100 Cl.5 Lcl "Carrollton" 504-86x-;PBX 'homes' on)