In the US, the standard for labeling is <a href="http://www.hellermanntyton.us/assets/6A705996-74CC-4505-BC11-A60EF28585CE.pdf">ANSI/TIA/EIA 606A</a>. That said, this is a voluntary standard and you are welcome to tune it to suit your needs. The <a href="http://www.milspecwireonline.com/?gclid=CJXJn8_S-5gCFQ8eDQodbG3Ulw">MIL</a> also has specs, but I'm afraid I'm not familiar with the exact number. In short, you label one end of a cable with the location of the other end. This holds true for data centers and horizontal cabling. That doesn't work for everyone, but it works for most. Your telecom areas are located by floor number, location, etc. -- the same holds true for your work area. In a data center, you label your tiles alpha-numerically on an X and Y axis. The position of the right front corner of the cabinet on your floor grid is the cabinet name (by location). Again, you can change this to suit you.