The topology structure of your network is the backbone. While many networks are "flat" without subnetworks and multiple routers, a skilled specialist can diagram a new network structure that can greatly enhance your security level. For example, an office can be on a separate firewall than the warehouse, and a wireless network, exchange server or web server should be on a separate network with separate routing or DHCP. Comprehensive network design and access strategies include firewalls, intrusion detection systems and VPN networks.

An on-site Infrastructure assessment and proposed network diagram. Starting at $380
Written estimate for parts and labor to infrastructure "upgrade"