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Hi, guys, and welcome back, having talked about the composition of a domain name, we will now proceed
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to discussing the context in which domain names exist only on the coasts.
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We compare DNS with a phonebook in the sense that names are mapped to numbers.
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That is where the similarities between a phone book and DNS.
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And however, and I will now expand on that.
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In the first case, a phone book is used as a single authority, a central database of all available
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names and their associated numbers within a specific geographic region.
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Consequently, all users of that specific region would need to obtain a copy of that database.
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This is an example of what we call flat name architecture, where there is no sophisticated internal
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structure and no clear relationships between the names themselves exist.
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In the case of Dennis, on the other hand, having a central database of all available domain names
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of the entire internet along with their IP addresses, that each of those names translates to is simply
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not feasible for several reasons.
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The first reason would be the administrative overhead involved in managing every possible domain name
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in the internet.
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Another reason would be that the flat name architectures that work with a central database did not scale
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well to name systems containing hundreds of thousands of machines.
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Another important reason would be that it's extremely difficult to ensure that domain names are unique
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across the entire namespace.
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Given these challenges, the designers of the NSA came up with the ingenious decision to move away from
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the flat name approach and adopt hierarchical name architecture, whereby a multiple level structure
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is used to organize names in a specific way and within the structure a particular device is can be determined
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by looking at its name as a result, instead of having a singular database of domain names.
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We have a globally distributed collection of databases forming a tree like structure that is indexed
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by domain names and where each domain name is essentially just a path in that large tree.
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In this globally distributed name, system administration is decentralized completely, and delegation
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is handed over to organizations, allowing this way many authorities to share in the registration and
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administrative process and take over the responsibility of managing their own data.
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By the same token, every organization administering a domain can further divided into subdomains,
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and each subdomain can in turn be delegated to other organizations, which are then entitled to change
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the data freely and even divide those subdomains into more subdomains and delegate those.
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Benefits.
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Decentralised administration, thanks to its ability to delegate authority to organizations, so easy
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management flexibility as it allows a namespace to scale and the internet to grow.
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And the guarantee that every domain name is unique.
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The district consists of the root name servers are the top, followed by the top level domain name servers,
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followed by authoritative name servers.
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In the next lecture, we're going to study the root name servers and the important role they play in
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the DNS namespace.
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Thank you for watching, guys, and I will see you in the next one.
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