meow 327 Indirect Comm

Indirect Communication

Communication through an intermediary with no direct coupling between sender and receiver

Space Uncoupling

The sender does not need to know the receiver's identity and vice versa

Time Uncoupling

The sender and receiver can have independent lifetimes

Group Communication

A communication method where a message is sent to a group and delivered to all members

Multicast Communication

Sending a message to multiple recipients in a group

Reliability in Multicast

Ensures messages are delivered without loss, duplication, or corruption

FIFO Ordering

Messages from the same sender are received in the order they were sent

Causal Ordering

Messages maintain causal relationships; if message A causes message B, A is delivered first

Total Ordering

All processes receive messages in the same order

Group Membership Management

Handles joining and leaving of processes in a group

Failure Detection

Identifies failed members in a distributed system

Publish-Subscribe System

A communication model where publishers send events and subscribers receive relevant ones

Event Service

Manages event distribution between publishers and subscribers

Message Queues

A point-to-point communication model using a queue

Enterprise Application Integration (EAI)

Integrates different enterprise applications through messaging

Distributed Shared Memory (DSM)

Abstracts distributed memory as a single shared memory space

Tuple Space Communication

Processes place tuples in a shared space where others can read or remove them

Indirect communication requires the sender to know the receiver's identity

False

Publish-subscribe systems use a push-based model where subscribers receive all events

False – they receive only subscribed events.

Tuple space communication allows mutable tuples

False – tuples are immutable

Group communication guarantees message delivery to all members

True

Causal ordering ensures all processes receive messages in the same order

False – that is total ordering

Which of the following is an advantage of indirect communication?

Flexibility in system design

What is the main purpose of a message queue?

Store messages temporarily for asynchronous processing

Which type of ordering guarantees all recipients receive messages in the same sequence?

Total ordering

Which is NOT a subscription filtering model in a publish-subscribe system?

Sender-based

What is a key disadvantage of indirect communication?

Increased system complexity

What are two primary characteristics of indirect communication?

Space uncoupling and time uncoupling.

What are the three types of message ordering in group communication?

FIFO ordering, causal ordering, total ordering.

Name two applications of publish-subscribe systems.

Financial information systems, real-time monitoring applications.

What are the three key tasks of group membership management?

Managing group changes, detecting failures, notifying members of changes.

Why is distributed shared memory primarily used in parallel applications?

It allows processes to share data efficiently without direct physical memory sharing.

Subscription Filtering Models: Channel-based

Predefined topics

Subscription Filtering Models: Topic-based

Messages categorized under topics

Subscription Filtering Models: Content-based

Filters based on message content

Subscription Filtering Models: Type-based

Based on data type of messages

Tuple Operations: Write

Adds a tuple to space

Tuple Operations: Read

Retrieves a tuple without removing it

Tuple Operations: Take

Retrieves and removes a tuple

In a publish-subscribe system, which of the following is NOT a key feature?

Subscribers receive all events published by publishers

Message queues in a point-to-point communication model ensure that messages are processed in the order they arrive

True

Causal ordering ensures that all processes see messages in the same order, regardless of the sender

False (Causal ordering maintains the cause-effect relationship, but not necessarily the same order for all processes.)

Group communication guarantees that every message will be received by all members of the group

True

A key advantage of publish-subscribe systems is that they offer synchronous message delivery

False (Publish-subscribe systems are generally asynchronous.)

Failure detection systems help in identifying active system components and eliminating failed nodes

True

What is the main difference between multicast communication and broadcast communication?

Multicast communication sends messages to a specific group of recipients, whereas broadcast sends messages to all members of the network.

What are the benefits of using a publish-subscribe model over direct communication between sender and receiver?

It decouples senders and receivers, allows asynchronous communication, and provides scalability as subscribers can join or leave without impacting the publisher

What is the purpose of group membership management in distributed systems?

It ensures that processes can join or leave groups seamlessly, and manages communication within the group, including handling failures.

How does distributed shared memory (DSM) help with parallel computing?

DSM allows processes to access shared data as if it were in a single memory space, enabling efficient coordination without direct physical memory sharing

Why is total ordering important in group communication?

Total ordering ensures that all processes receive messages in the exact same order, which is crucial for consistency in distributed systems.