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CCNA Quick Reference Sheets (CCNA Exam 640-802) by Jim Doherty, Eric Rivard

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Chapter 2. Understanding TCP/IP

TCP/IP Overview

The TCP/IP suite of protocols is used to communicate across any set of interconnected networks. The protocols initially developed by DARPA are well suited for communication across both LANs and WANs.

The protocol suite includes Layer 3 and Layer 4 specifications as well as specifications for higher-layer applications, such as e-mail and file transfer.

Internet Protocol (IP)

IP is a connectionless protocol that provides best-effort delivery routing of packets.

IP has the following characteristics:

  • Operates at Layer 3 of the OSI (network) and Layer 2 of the TCP/IP (Internet) model

  • Is connectionless

  • Uses hierarchical addressing

  • Provides best-effort delivery of packets

  • Has no built-in data recovery

Figure 2-1

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