Circuit numbering scheme - best practice?

Justin M. Streiner streiner at
Sat Jan 17 00:10:28 UTC 2009

On Fri, 16 Jan 2009, Jay Hennigan wrote:

> Any suggestions from those who have been down this road as to a schema that 
> makes sense and is scalable?  Are there documented best practices?

Many of the RBOCs (if they can be called that anymore) use the Common 
Language Circuit Identifier (CLCI) nomenclature for identifying circuits.
Many large carriers, especially those that have spent more time buying up 
competitors then integrating previous acquisitions' provisioning systems, 
have a mish-mash of different circuit numbering schemes, depending on 
whose underlying plant and provisioning systems were used to build the 
circuit in the first place.

Like you, I have seen everything from telcos that just use a number and 
not much else, to telcos that try to tell someone's life story in the form 
of a circuit ID, to forms that are somewhere in between.  I won't say one 
is better than another, but I do favor shorter ones, if for no other 
reason than they're easier to key into provisioning systems, interface 
desciptions and put on wire labels :)

I also got into the habit a long time ago of recording every circuit ID 
for a particular circuit.  Many of the circuit I dealt with were long-haul 
circuits, or were provisioned by a LEC and had to be handed off to an 
incumbent carrier for final delivery to the customer, and one particular 
LEC burned me several times by stating, "Oh, I see we hand that off to 
$TELCO... I don't have a circuit ID for that piece....".

Since you have the luxury of starting from scratch, you have the option of 
creating a system that best fits your needs.  If you have or can build a 
provisioning system that captures all of the information you need, then 
you can get away with a simpler ID, such as a plain number.  The 
information you want to capture would depend on the type of circuit, but 
would generally include things like carrier/customer handoff points, 
router interface/switch ports, VLANs, MPLS labels, patch assignments, 

It's also a good idea to come up with a standard format for identifying 
your facilities/rooms/racks if you haven't already.  Many providers use 
Common Language Location Identifier (CLLI) codes for this, which is 
another telco hold-over, but you can ID them however you want, as long as 
it makes sense to you and scales as you grow your network.


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