A Partial List of Networking
and Support Services include:

Local (LAN)
Wide area (WAN),
Virtual private networking (VPN)
Wireless networks
Firewalls
Hubs, switches, routers
System and device configuration
Network services include:
Network design, installation and maintenance
Network systems diagnosis and analysis
Network cable and jack installation,
Network troubleshooting
Security testing
Intrusion detection systems (IDS)