Protocol Stack Architecture

The protocol stack or network stack is an implementation of a computer networking protocol suite or protocol family. Some of these terms are used interchangeably but strictly speaking, the suite is the definition of the communication protocols, and the stack is the software implementation of them.

Individual protocols within a suite are often designed with a single purpose in mind. This modularization simplifies design and evaluation. Because each protocol module usually communicates with two others, they are commonly imagined as layers in a stack of protocols. The lowest protocol always deals with low-level interaction with the communications hardware. Each higher layer adds additional capabilities. User applications usually deal only with the topmost layers.

In practical implementation, protocol stacks are often divided into three major sections: media, transport, and applications. A particular operating system or platform will often have two well-defined software interfaces: one between the media and transport layers, and one between the transport layers and applications. The media-to-transport interface defines how transport protocol software makes use of particular media and hardware types and is associated with a device driver. For example, this interface level would define how TCP/IP transport software would talk to the network interface controller. Examples of these interfaces include ODI and NDIS in the Microsoft Windows and DOS environment. The application-to-transport interface defines how application programs make use of the transport layers. For example, this interface level would define how a web browser program would talk to TCP/IP transport software. Examples of these interfaces include Berkeley sockets and System V STREAMS in Unix-like environments, and Winsock for Microsoft Windows.

 

Service Architecture

Service-Oriented Architecture

Service-Oriented Architecture (SOA) is an architectural approach in which applications make use of services available in the network. In this architecture, services are provided to form applications, through a communication call over the internet.

• SOA allows users to combine a large number of facilities from existing services to form applications.

• SOA encompasses a set of design principles that structure system development and provide means for integrating components into a coherent and decentralized system.

• SOA based computing packages functionalities into a set of interoperable services, which can be integrated into different software systems belonging to separate business domains.

There are two major roles within Service-oriented Architecture:

1. Service provider: The service provider is the maintainer of the service and the organization that makes available one or more services for others to use. To advertise services, the provider can publish them in a registry, together with a service contract that specifies the nature of the service, how to use it, the requirements for the service, and the fees charged.

1. Service consumer: The service consumer can locate the service metadata in the registry and develop the required client components to bind and use the service.

Components of SOA:

Guiding Principles of SOA:

1. Standardized service contract: Specified through one or more service description documents.

1. Loose coupling: Services are designed as self-contained components, maintain relationships that minimize dependencies on other services.

1. Abstraction: A service is completely defined by service contracts and description documents. They hide their logic, which is encapsulated within their implementation.

1. Reusability: Designed as components, services can be reused more effectively, thus reducing development time and the associated costs.

1. Autonomy: Services have control over the logic they encapsulate and, from a service consumer point of view, there is no need to know about their implementation.

1. Discoverability: Services are defined by description documents that constitute supplemental metadata through which they can be effectively discovered. Service discovery provides an effective means for utilizing third-party resources.

1. Composability: Using services as building blocks, sophisticated and complex operations can be implemented. Service orchestration and choreography provide a solid support for composing services and achieving business goals

IP Addressing

 IP Addressing

 IP addresses are managed by the Internet Assigned Numbers Authority (IANA), which has overall responsibility for the Internet Protocol (IP) address pool, and by the Regional Internet Registries (RIRs) to which IANA distributes large blocks of addresses.

The RIRs manage, distribute, and publicly register IP addresses and related Internet number resources, such as Autonomous System Numbers (ASN) and reverse Domain Name System (DNS ) delegations within their respective regions. They do this according to policies which are developed within their respective regional communities, through open and bottom-up processes.