Data Networks: Routing, Security, and Performance Optimization
Provides coverage of routing, security, multicasting, and advanced design topics, as well as strategies for overcoming challenges in network design and management.
TABLE OF CONTENTS Data Networks: Routing, Security, and Performance Optimization
2.3 Name-to-address mapping
2.3 Name-to-address mapping
Most people have difficulty remembering numbers, so a user-friendly scheme is often required for real networks, where names are used to refer to computer systems, networking devices, and services. In essence there are two basic ways to use names on a network, as follows:
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By static mapping tables associating addresses with names, such as the /etc/hosts file under UNIX.
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By using a dynamic name resolution system, such as the Domain Name Service (DNS).
Another key advantage of mapping names to addresses is that there is another layer of abstraction between users and resources. This enables hosts and network devices to be swapped out or modified without affecting users or services. For example, a file server is installed called BigDisk, and is mapped to 192.162.35.5. Subsequently this host is reassigned to other duties (perhaps because a host supporting a disk array is subsequently installed). The new host could be located on a different subnet and simply mapped to the name BigDisk without the user ever knowing.
In this section we discuss naming techniques and services used to complement the network design. Note that advanced applications such as load balancing and performance optimization of these services are covered in reference [4].
2.3.1 Static name service: The hosts file
The simplest method of mapping names to addresses can be achieved using a simple text lookup file, held locally on each device. On many operating systems this file is referred to as the hosts file. Under UNIX, for example, this function...
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