1. DISTRIBUTED SYSTEMS Principles and Paradigms Second Edition ANDREW S
DISTRIBUTED SYSTEMS Principles and Paradigms Second Edition ANDREW S. TANENBAUM MAARTEN VAN STEEN Chapter 5 Naming (skip 5.1, 5.3)
Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

2. 5.1 Names, Identifiers, And Addresses
A name is a string of bits or characters that is used to refer to an entity.
The name of an access point of an entity is called an address.
A name for an entity is location independent if it is independent from its address
Properties of a true identifier:
An identifier refers to at most one entity.
Each entity is referred to by at most one identifier.
An identifier always refers to the same entity
Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

3. 5.2 Flat Naming
Figure 5-1. The principle of forwarding pointers using (client stub, server stub) pairs.
Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

4. Forwarding Pointers (2)
Figure 5-2. Redirecting a forwarding pointer by storing a shortcut in a client stub.
Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

5. Home-Based Approaches
Figure 5-3. The principle of Mobile IP.
Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

6. Distributed Hash Tables General Mechanism
FTp[i]=succ(p+2i-1)
Figure 5-4. Resolving key 26 from node 1 and key 12 from node 28 in a Chord system.
Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

7. Hierarchical Approaches (1)
Figure 5-5. Hierarchical organization of a location service into domains, each having an associated directory node.
Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

8. Hierarchical Approaches (2)
Figure 5-6. An example of storing information of an entity having two addresses in different leaf domains.
Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

9. Hierarchical Approaches (3)
Figure 5-7. Looking up a location in a hierarchically organized location service.
Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

10. Hierarchical Approaches (4)
Figure 5-8. (a) An insert request is forwarded to the first node that knows about entity E.
Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

11. Hierarchical Approaches (5)
Figure 5-8. (b) A chain of forwarding pointers to the leaf node is created.
Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

12. Hierarchical Implementations: LDAP (1)
5.4 Attribute-Based Naming
Hierarchical Implementations: LDAP (1)
Figure A simple example of an LDAP (Lightweight Directory Access Protocol) directory entry using LDAP naming conventions.
Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

13. Hierarchical Implementations: LDAP (2)
Figure (a) Part of a directory information tree. (b) Two directory entries
having Host_Name as RDN.
Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

14. Decentralized Implementation
Every path is assigned a unique hash value
Skip p.224 about range query
Figure (a) A general description of a resource. (b) Its representation as an AVTree.
Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

15. Semantic Overlay Networks
No a priori deterministic scheme
Small world effect
Figure Maintaining a semantic overlay through gossiping.
Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved