1.17 Summary

1.17 Summary

This chapter has been a whirlwind tour of the TCP/IP protocol suite, introducing many of the terms and protocols that we discuss in detail in later chapters.

The four layers in the TCP/IP protocol suite are the link layer, network layer, transport layer, and application layer, and we mentioned the different responsibilities of each. In TCP/IP the distinction between the network layer and the transport layer is critical: the network layer (IP) provides a hop-by-hop service while the transport layers (TCP and UDP) provide an end-to-end service.

An internet is a collection of networks. The common building block for an internet is a router that connects the networks at the IP layer. The capital-I Internet is an internet that spans the globe and consists of more than 10,000 networks and more than one million computers.

On an internet each interface is identified by a unique IP address, although users tend to use hostnames instead of IP addresses. The Domain Name System provides a dynamic mapping between hostnames and IP addresses. Port numbers are used to identify the applications communicating with each other and we said that servers use well-known ports while clients use ephemeral ports.



TCP.IP Illustrated, Volume 1. The Protocols
TCP/IP Illustrated, Vol. 1: The Protocols (Addison-Wesley Professional Computing Series)
ISBN: 0201633469
EAN: 2147483647
Year: 1993
Pages: 378

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