Creating a Circuit ID Format

We are building a new fiber network, and need help creating a circuit ID format to for new fiber circuits. Is there a guide or standard for fiber circuit formats? Does the circuit ID change when say a customer upgrades for 100Mbps to 1Gbps port? What do the larger carriers do? Any advice on creating a circuit ID format for a brand new fiber network? Originally we ran a CLEC using a LECs copper, and our circuit ID was historically a telephone number for DSL circuits. The ILEC had a complex method for assigning circuit IDs. I am sure anything will work as long as you keep track of it, but any advice would be great!