What are the priorites of work and responsibilities of the Ground Lines of Communication GLOC?

I believe GLOC security is a traditional mission for MP units. Whether they have the manning for this in the current TOE, I don't know. It is an additional responsibility of Scout/Reconnaissance units under Security, but the current iteration of the TOE doesn't provide the manning for it. Any mane it unit can perform the function, however.

I'm not really sure that GLOC is under one domain as more so its a global concept involving many such as EOD, Styker teams, scouts, air support, FOB's, JSS's, MP's and just about any one else if needed.
I think of GLOC in terms of deep, close, and rear areas and either in prograde or retrograde states.
Deep being in the shaping stages, close being very volatile, rear being rather secured yet still prone.
As GLOC is highly dynamic I think what force to project in order to keep things open depends on the SITREP at the time. As far as priorities I would bet force protection, logistics/supply then on to other less critical elements. If anything the ORBAT would dictate the capabilities of any military force via the identification, strength, command structure, and disposition of the personnel, units, and equipment deployed. Not sure who prepares the ORBAT maybe USCENTCOM.

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA309692

Priorities of Work (SCTPCS)
Security
Communication
Technical Maintenance
Personnel Hygiene
Chow
Sleep