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Naming (Domain Name System (DNS) (Two name servers for each domain…
Introduction
Names
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Pure names: contains no info about the object itself + must be looked up to obtain an address (vs. non-pure name)
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Domain Name System (DNS)
Maps human readable domain names to IP addresses and other kinds of attributes such as the type of host and time for which the DNS entry remains valid
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Host information: usually not provided by the administrator because it constitutes a security problem
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Names and services
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When a service allocates a resource, it generates a unique name -> client to the service needs to provide this name to access the resource
Clients can specify the desired name for a new resource to the service -> service needs to ensure name is locally uniqu
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Name services
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Motivations
Unification: resources managed by different services use the same naming scheme, as in the case of URIs
Integration: to share resources that were created in different administrative domains requires naming those resources -> without common naming servcice, the administrative domains may use entirely different name formats
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Name spaces
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Alias: typically substituted by the name service for another name that is harder to remember OR a common name that allows ease of access to a resource which is managed using some other name
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Naming domain: name space where there is a single overall administrative authority for assigning names within it; admin authority usually delegated by dividing a domain into sub-domains
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Naming strategies
Absolute names
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Provides a complete address to a file, including both server and path names
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Global name space
All nodes have an identical name space: path + name of file on one machine will be the same on every other machine, regardless of where it is stored
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When a user access a file, the server sends a copy of it to the client machine where it is cached
Advantages
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Storage servers are able to seamlessly move files around because clients always contact the server to learn where files are located
Disadvantages
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Can lead to performance problems, particularly when the scale of the system grows