TCP/IP Networking Model
Exam: Cisco 640-822 - Interconnecting Cisco Networking Devices Part 1
Networking model also termed as networking blueprint is defined as a broad arrangement of documents. Each document is to define a particular function. Some define protocol while others define the physical needs for the purpose of networking. One can build his own network, prepare a software or networking cards.
As on date, the computer networking world utilizes a networking model - TCP (transmission control protocol) /IP (internet protocol). In the absence of networking protocols, the protocols so created by the vendors used to support only his computer. For example-if a company used to buy computers from 2 different vendors, two different networks had to be created.
Though the vendor-defined models worked well, ISO has aims with reference to the OSI model:
- Standardization of data networking protocols and
- Allowing communication between all systems spread the world over.
Creation of an networking model that was vendor-neutral and public was initiated by a defense contract of us department. The result was TCP/IP - a networking model that was open. Later, TCP/IP became popular as compared to OSI in 1990s. The OSI model was left behind as the standardization process in it was slower in comparison to TCP/IP.
TCP/IP working model communicates in-between the computers through a large collection of protocols. TCP/IP uses documents called Requests for Comments. It avoids the repentance of work already performed.
There are two alternative models for TCP/IP
- The original TCP/IP model
- The updated TCP/IP model
The Two TCP/IP Networking Models
The Application Layer
The application helps in providing services to the application software. It defines the services required by the application. Quiet famous TCP/IP application is a web browser. Some architecture layer example protocols are HTTP, POP3, SMTP. The full version of most web addresses-also called universal resource locators (URL)-begin with the letters "http," which means that HTTP is used to transfer the web pages.
The Transport Layer
Smaller number of protocols is used in the transport layer. Commonly used protocols are Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP). Transport layer helps in providing services to the application layer. The adjacent-layer interaction- it refers to the working of adjacent layers together in a working model.
The same layer interaction- it refers to the communication of same layers between two computers. It is the process of setting and interpreting the information in the headers.
The Internet Layer
The internet layer uses a smaller number of protocols including one major protocol i.e. internet protocol. IP provides addressing and routing. The internet protocol works like a postal service. IP defines address in a unique manner so that it can be identified in a network.
The Network Access Layer
It provides services to the layers above it as shown in the model. It includes a large number of protocols and standards. It includes all the variations of Ethernet, several LAN standards and popular WAN standards. Network access layer divides its functions in two layers: data link and physical as embedded in the table.
