Hi,
CLECs may terminate circuits in a couple of different ways, and how they choose to do so might have a lot to do with their size and geography related to the ILECs they are working with and the region that they serve. Generally speaking, the last mile of a circuit or the local loop would be terminated at the demarc from the ILEC and get carried back to the ILEC’s nearest CO.
The CLEC may or may not have colocation space in that same CO as the ILEC to terminate the circuit. Depending on the size of a deployment, the CLEC might have a single central office where the circuits and services for their customers finally terminate, and they might have facilities that terminate to the near-end ILEC CO to carry the leased circuits. The ILEC may then need to carry those circuits to different remote offices.
For an example of leased DS1 circuits through ILECs, a CLEC might have one central office where they have a telephony switch and routers for customer voice and data termination, and they might have a few channelized OC3s going out to ILEC COs to carry the DS1s. The ILEC may then break out the DS1s at that local CO for the local loops to be terminated at the customer's demarc, or they might carry them out to other COs depending on the geographic range for the service region.
In short, the CLEC might have POP/colo space in the local CO that terminates the local loop from the ILEC, or it might require further backhaul across the ILEC facilities/offices to reach the final termination at a CLEC CO. How this might be setup would depend on size and geographic range of the deployment, if there is even colocation space in certain offices that is available, and if the type of services that are offered need to be centrally terminated or can be terminated in remote POP/colo spaces when possible.
Hope this helps!
