Naming in Distributed Systems Flashcards

Flashcards about Naming in Distributed Systems

What are the three naming concepts discussed in the lecture?

Flat Naming, Structured Naming, Attribute-based Naming

What are the key elements in naming of distributed systems?

Names, Identifiers, and Addresses

In a distributed system, what is a 'name'?

A string of bits or characters used to refer to an entity.

What is an identifier in a distributed system?

A special name that uniquely identifies an entity.

What are the three properties of a true identifier?

Each identifier refers to at most one entity, each entity is referred to by at most one identifier, and an identifier always refers to the same entity.

What are the goals of naming systems?

Scalable to arbitrary size, have a long lifetime, be highly available, have fault isolation, tolerate mistrust

What are the solutions to the flat naming resolution problem?

Simple solutions (broadcasting), home-based approaches, distributed hash tables (structured P2P), hierarchical location service.

How does broadcasting work in the context of flat naming?

Each entity compares the requested ID with its own ID; the target entity returns its current address.

What is an advantage of using forwarding pointers?

Support for mobile nodes.

How do home-based approaches facilitate communication with mobile entities?

The home agent gives the new location to the client (efficient but not transparent) or forwards the messages (transparent but may not be efficient).

How does a Distributed Hash Table (DHT) resolve a flat ID?

Each node is assigned a random m-bit identifier and every entity is assigned a unique m-bit key; the entity falls under the jurisdiction of the node with the smallest id >= k.

How is key resolution achieved in DHT?

Linearly resolve a key k to the address of succ(k) using neighbors.

How does Chord improve key resolution?

Node p will forward it to node q with index j in Fp where q = FTp[j] <= k < FTp[j+1]

What is the basic idea behind Hierarchical Location Services (HLS)?

Building a large-scale search tree where the underlying network is divided into hierarchical domains.

What is a name space?

A collection of valid names forming a directed graph.

What is name resolution?

Looking up a name by starting at a directory node and following labels until reaching the desired node.

What are the two ways of aliasing in naming graphs?

Hard links and Soft Links

What is mounting in the context of name spaces?

A technique where two or more name spaces can be merged transparently.

What are the three logical layers in a distributed name space?

Global, administrational, and managerial layers.

What are the two ways of name resolution implementation

Iterative and recursive

What makes the Domain Name System scalable?

Partitioned database and caching, replication

What are some common domain names in DNS?

com, edu, gov, mil, net, org, int, and country codes.

What does a zone contain in DNS terms?

Attribute data for names in a domain minus the sub-domains administrated by lower-level authorities

What are the functions of the DNS server?

Getting the IP addresses, mail host, reverse resolution, information on hardware and OS

What is the role of the client in resolution?

Is responsible for detecting delivery of stale data and recovering

What is attribute-based naming?

Looking up entities by means of their attributes.

What are the solutions for expensive lookup operations in directory services?

Combination with traditional structured naming system or DHT-based decentralized implementation.

What does an LDAP directory service consist of?

A set of records where each entry is made up of (Attribute, Value(s)) pairs.