Fundamentals of Communications and Networking, 3rd Edition

CHAPTER SUMMARY

Layer 1 of the OSI Reference Model is the Physical Layer. The Physical Layer provides the wiring and electrical signaling, or optical signaling if fiber optic cabling is used. OSI Layer 2, the Data Link Layer, is close enough to the Physical Layer to provide fast data transfer; however, because it is separate from the Physical Layer, it also can provide flexibility to group and separate nodes based on communication needs.

Layer 2 networking or switching means forwarding or filtering decisions are made by examining the destination MAC address of the Ethernet frame. Layer 2 switching can support high-speed network connections with minimal delays. Depending on the physical environment and quantity of endpoints, a Layer 2 network ...