Interprocess Communication and TCP/IP Model Overview, Multicast Communication and TCP Overview, Introduction to Cloud Computing Concepts and Models

TCP/IP Model

Framework for network communication protocols.

Transport Protocols

Enable communication between application processes.

Sender

Breaks messages into segments for transmission.

Receiver

Reassembles segments into complete messages.

User Datagram Protocol (UDP)

Unreliable, unordered delivery of segments.

Transmission Control Protocol (TCP)

Reliable, in-order delivery of segments.

3-way handshake

Connection setup method in TCP.

Flow Control

Regulates data transmission rate between sender and receiver.

Congestion Control

Manages packet loss during network congestion.

Corrupted Packets

Packets that arrive with errors and are discarded.

Retransmission

Resending lost packets to ensure delivery.

Synchronous Communication

Blocking communication requiring acknowledgment.

Asynchronous Communication

Non-blocking communication without immediate acknowledgment.

Queue

Storage for messages at the destination.

Port

Endpoint for communication, unique to each process.

Point-to-Point Message Service

Reliable delivery despite packet drops.

Message Integrity

Ensures messages arrive uncorrupted and unduplicated.

Message Ordering

Messages delivered in the order sent.

Sockets

Endpoints for sending and receiving messages.

InetAddress Class

Represents Internet addresses in Java.

Datagram

Message unit sent via UDP without acknowledgment.

Socket Binding

Associating a socket with a local port.

Timeouts

Prevent indefinite waiting during communication.

Checksum

Ensures message integrity in UDP.

DatagramPacket Class

Holds message data, length, IP, and port.

DatagramSocket Class

Supports sending and receiving UDP datagrams.

AF_UNIX

Address format for UNIX pathname.

AF_INET

Address format for host and port.

UDP Applications

Used in multimedia streaming and DNS queries.

Multicast communication

A multicast sends a single message from one process to each of the members of a group of processes.

Sender in multicast

The sender is unaware of the identities of the individual recipients and of the size of the group.

IP multicast

IP multicast is built on top of the Internet Protocol (IP).

Multicast group address

A multicast group is specified by a Class D Internet address, an address whose first 4 bits are 1110 in IPv4.

Membership of multicast groups

The membership of multicast groups is dynamic, allowing computers to join or leave at any time and to join an arbitrary number of groups.

Application programming level for IP multicast

At the application programming level, IP multicast is available only via UDP.

Multicast routers

IP packets can be multicast both on a local network and on the wider Internet.

224.0.0.1

All systems on the local subnet.

224.0.0.2

All routers on the local subnet.

224.0.0.11

Mobile agents on the local subnet.

MulticastSocket

The Java API provides a datagram interface to IP multicast through the class MulticastSocket, which is a subclass of DatagramSocket with the additional capability of being able to join multicast groups.

joinGroup method

A process can join a multicast group with a given multicast address by invoking the joinGroup method of its multicast socket.

leaveGroup method

A process can leave a specified group by invoking the leaveGroup method of its multicast socket.

TCP

Transmission Control Protocol (TCP) is connection-oriented.

TCP session

Explicit set-up and tear-down of TCP session.

Stream-of-bytes service

Sends and receives a stream of bytes, not messages.

Reliable delivery in TCP

Reliable, in-order delivery with checksums to detect corrupted data.

Flow control

Prevent overflow of the receiver's buffer space.

Congestion control

Adapt to network congestion for the greater good.

Acknowledgments

Positive: 'okay' or 'ACK'; Negative: 'please repeat that' or 'NACK'.

Timeout by the sender

Don't wait indefinitely without receiving some response.

Retransmission by the sender

After receiving a 'NACK' from the receiver or receiving no feedback from the receiver.

Challenges of Reliable Data Transfer

Over a lossy channel with bit errors, some data are missing, and some bits are corrupted.

Checksum in TCP

Used to detect corrupted data at the receiver, leading the receiver to drop the packet.

Sequence numbers in TCP

Used to detect missing data and for putting the data back in order.

Cloud Computing

Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.

Cloud Computing

Cloud Computing refers to manipulating, configuring, and accessing the applications online.

Cloud Computing

It offers online data storage, infrastructure and application.

Cloud Computing

Cloud Computing is both a combination of software and hardware based computing resources delivered as a network service.

Deployment Models

Deployment models define the type of access to the cloud, i.e., how the cloud is located.

Public Cloud

The Public Cloud allows systems and services to be easily accessible to the general public.

Private Cloud

The Private Cloud allows systems and services to be accessible within an organization.

Community Cloud

The Community Cloud allows systems and services to be accessible by a group of organizations.

Hybrid Cloud

The Hybrid Cloud is a mixture of public and private cloud, where critical activities are performed using private cloud while non-critical activities are performed using public cloud.

Service Models

Service Models are the reference models on which the Cloud Computing is based.

Infrastructure as a Service (IaaS)

IaaS is the delivery of technology infrastructure as an on-demand scalable service.

Infrastructure as a Service (IaaS)

IaaS provides access to fundamental resources such as physical machines, virtual machines, virtual storage, etc.

Platform as a Service (PaaS)

PaaS provides the runtime environment for applications, development & deployment tools, etc.

Platform as a Service (PaaS)

PaaS provides all of the facilities required to support the complete lifecycle of building and delivering web applications and services entirely from the Internet.

Software as a Service (SaaS)

SaaS model allows to use software applications as a service to end users.

Software as a Service (SaaS)

SaaS is a software delivery methodology that provides licensed multi-tenant access to software and its functions remotely as a Web-based service.

Advantages of Cloud Computing

Lower computer costs, Improved performance, Reduced software costs, Instant software updates, Improved document format compatibility, Unlimited storage capacity, Increased data reliability, Universal document access, Latest version availability, Easier group collaboration, Device independence.

Disadvantages of Cloud Computing

Requires a constant Internet connection, Does not work well with low-speed connections, Features might be limited, Can be slow, Stored data can be lost, Stored data might not be secure.