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Unformatted text preview: u.edu The set of domain names forms a hierarchy and each domain name encodes its position in the hierarchy. An example is the easiest way to understand this. Figure 12.10 shows a portion of the domain name hierarchy. The hierarchy is represented as a tree. The nodes of the tree represent domain names that are formed by the path back to the root. Sub-trees are referred to as subdomains. The ﬁrst level in the hierarchy is an unnamed root node. The next level is a collection of ﬁrst-level domain names that are deﬁned by a non-proﬁt organization called ICANN (Internet Corporation for Assigned Names and Numbers). Common ﬁrst-level domains include com, edu, gov, org, and net. At the next level are second-level domain names such as cmu.edu, which are assigned on a ﬁrst-come ﬁrst-serve basis by various authorized agents of ICANN. Once an organization has received a second-level domain name, then it is free to create any other new domain name within its subdomain. 12.3. THE GLOBAL IP INTER...
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- Spring '10
- The American