NIC teaming involves combining multiple network interfaces on a server to act as a single unit. This practice not only increases the available bandwidth but also provides redundancy, so if one NIC fails, the others can continue to operate, maintaining network connectivity. Load balancing helps to distribute traffic evenly across the NICs. A switch manages multiple VLANs to segregate and manage network traffic, a router establishes a connection between different networks, and full duplex sets the communication to send and receive signals simultaneously but doesn't aggregate bandwidth or provide redundancy.