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Naming - PowerPoint PPT Presentation

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Naming. Naming. Access point & address Location independent naming Identifier It refers to at most one entity Each entity has at most one id An id always refers to the same entity Name-to-address binding Name resolution vs message routing Flat naming Broadcasting and multicasting.

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  • Access point & address

  • Location independent naming

  • Identifier

    • It refers to at most one entity

    • Each entity has at most one id

    • An id always refers to the same entity

  • Name-to-address binding

  • Name resolution vs message routing

  • Flat naming

    • Broadcasting and multicasting

Naming versus locating entities

Naming versus Locating Entities

  • Direct, single level mapping between names and addresses.

  • T-level mapping using identities.

Forwarding pointers

Forwarding Pointers

  • The principle of forwarding pointers using (proxy, skeleton) pairs.

Forwarding pointers1

Forwarding Pointers

  • Redirecting a forwarding pointer, by storing a shortcut in a proxy.

Home based approaches

Home-Based Approaches

  • The principle of Mobile IP.

Distributed hash tables

Distributed Hash Tables


    • FT_p[i] = first node in range [p+2^(i-1), p+2^i).

    • Enhance by storing r nodes in the range and during lookup use closest to query



Searching for 26 from 1

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Hierarchical approaches

Hierarchical Approaches

  • Hierarchical organization of a location service into domains, each having an associated directory node.

Hierarchical approaches1

Hierarchical Approaches

  • An example of storing information of an entity having two addresses in different leaf domains.

Hierarchical approaches2

Hierarchical Approaches

  • Looking up a location in a hierarchically organized location service.

Hierarchical approaches3

Hierarchical Approaches

  • An insert request is forwarded to the first node that knows about entity E.

  • A chain of forwarding pointers to the leaf node is created.

Pointer caches

Pointer Caches

  • Caching a reference to a directory node of the lowest-level domain in which an entity will reside most of the time.

Pointer caches1

Pointer Caches

  • A cache entry that needs to be invalidated because it returns a nonlocal address, while such an address is available.

Scalability issues

Scalability Issues

  • The scalability issues related to uniformly placing subnodes of a partitioned root node across the network covered by a location service.

Structured name spaces

Structured Name Spaces

  • A general naming graph with a single root node.

Absolute vs relative path names

Name spaces

Name Spaces

  • The general organization of the UNIX file system implementation on a logical disk of contiguous disk blocks.

Linking and mounting

Linking and Mounting

  • The concept of a symbolic link vs a hard link explained in a naming graph.

Linking and mounting1

Linking and Mounting

  • Mounting remote name spaces through a specific process protocol.

  • Mount point vs mounting point

Linking and mounting2

Linking and Mounting

  • Organization of the DEC Global Name Service

Name space distribution

Name Space Distribution

  • An example partitioning of the DNS name space, including Internet-accessible files, into three layers.

Name space distribution1

Name Space Distribution

  • A comparison between name servers for implementing nodes from a large-scale name space partitioned into a global layer, as an administrational layer, and a managerial layer.

Implementation of name resolution

Implementation of Name Resolution

  • The principle of iterative name resolution.

Implementation of name resolution1

Implementation of Name Resolution

  • The principle of recursive name resolution.

Implementation of name resolution2

Implementation of Name Resolution

  • Recursive name resolution of <nl, vu, cs, ftp>. Name servers cache intermediate results for subsequent lookups.

Implementation of name resolution3

Implementation of Name Resolution

  • The comparison between recursive and iterative name resolution with respect to communication costs.

The dns name space

The DNS Name Space

  • The most important types of resource records forming the contents of nodes in the DNS name space.

Dns implementation

DNS Implementation

  • An excerpt from the DNS database for the zone

Dns implementation1

DNS Implementation

  • Part of the description for the domain which contains the domain.

Attribute based naming

Attribute-based naming

  • Describe an entity via (attribute,value) pairs

    • Partial match queries in DB lingo

  • LDAP and X.500

  • Scalability issues

    • Decrentralized implementations

      • Attribute-value tree: hash-index for all paths to nodes in XML-like tree

The x 500 name space

The X.500 Name Space

  • A simple example of a X.500 directory entry using X.500 naming conventions.

The x 500 name space 2

The X.500 Name Space (2)

  • Part of the directory information tree.

The x 500 name space 3

The X.500 Name Space (3)

  • Two directory entries having Host_Name as RDN.

The problem of unreferenced objects

The Problem of Unreferenced Objects

  • An example of a graph representing objects containing references to each other.

Reference counting 1

Reference Counting (1)

  • The problem of maintaining a proper reference count in the presence of unreliable communication.

Reference counting 2

Reference Counting (2)

  • Copying a reference to another process and incrementing the counter too late

  • A solution.

Advanced referencing counting 1

Advanced Referencing Counting (1)

  • The initial assignment of weights in weighted reference counting

  • Weight assignment when creating a new reference.

Advanced referencing counting 2

Advanced Referencing Counting (2)

  • Weight assignment when copying a reference.

Advanced referencing counting 3

Advanced Referencing Counting (3)

  • Creating an indirection when the partial weight of a reference has reached 1.

Advanced referencing counting 4

Advanced Referencing Counting (4)

  • Creating and copying a remote reference in generation reference counting.

Tracing in groups 1

Tracing in Groups (1)

  • Initial marking of skeletons.

Tracing in groups 2

Tracing in Groups (2)

  • After local propagation in each process.

Tracing in groups 3

Tracing in Groups (3)

  • Final marking.

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