For buyers contracting authority
Pick 72315200 when the contract is about operating a network day to day, not fixing it when it breaks. The split that catches contracting authorities is the sibling, Data network support services (72315100): support resolves incidents and answers the helpdesk; management plans capacity, applies configuration changes, monitors, and keeps the estate current. Many operational contracts blend both, so set the primary CPV code by whichever dominates the statement of work.
If the deal bundles management and support evenly, the parent (72315000) is the cleaner tag than forcing it down one branch. Reserve 72315200 for scopes where proactive operation is the main job.
One more line to hold: this is a service code, not a hardware one. Buying or maintaining the routers, switches and cabling themselves belongs under equipment maintenance (50312300), even when the same supplier also runs the network.