Unit 4

Lesson 4 - The Network Layer

   Network Layer Protocols

Common protocols used by the Network Layer include:

X.25 is a connection-oriented, packet-switching protocol defined by the International Telecommunication Union-Telecommunications Standardization Sector (ITU-T). X.25 was widely used for public data networks, especially in Europe; however, it has been largely replaced by faster protocols based on the same basic approach.

Internet Protocol (IP), derived from X.25, is the primary Layer 3 protocol used across the Internet.

Internetwork Packet Exchange (IPX) is Novell NetWare's Network Layer protocol. It was derived from the Xerox Network System (XNS) protocol suite, which was used in early LANs.

Real Audio Clip

Why would it take longer for a router to forward data through a network than a switch?

   Activities

See the Activities and Extended Activities section in Unit 4 Lesson 4 in your textbook Introduction to Networking to test what you have learned so far.

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