Terms you'll need to understand:
Open Systems Interconnection (OSI) Reference model.
Connectionless protocol
Connection-oriented protocol
Encapsulation
Framing
Latency
Static route
Techniques you'll need to master:
The responsibilities of each layer of the OSI Reference model
The responsibilities of the three layers of the Cisco Hierarchical model and the types of device found at each layer
The steps involved in the Internetwork Troubleshooting model