?– Layer 1 devices provide the connection to the physical media and its encoding.
104 Chapter 1: Building a Simple Network
?– Layer 2 devices provide an interface between the Layer 2 device and the physical
media.
?– Layer 2 addresses are MAC addresses.
?– The network layer provides connectivity and path selection between two host systems.
?– Layer 3 addresses provide identi?¬?cation of a network and a host, such as an IP address.
?– Before a host can send data to another host, it must know the MAC address of the other
device.
?– ARP is a protocol that maps IP addresses to MAC addresses.
?– TCP uses a three-way handshake to establish a session before sending data.
?– Most operating systems offer tools to view the device ARP table as well as tools like
ping and traceroute to test IP connectivity.
Understanding Ethernet
A LAN is a common type of network found in home of?¬?ces, small businesses, and large
enterprises. Understanding how a LAN functions, including network components, frames,
Ethernet addresses, and operational characteristics, is important for an overall knowledge
of networking technologies.
This lesson describes LANs and provides fundamental knowledge about LAN
characteristics, components, and functions.
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