TCP/IP (Transmission Control Protocol/ Internet Protocol)

Transmission Control Protocol TCP/IP

             Transmission Control Protocol/Internet Protocol (TCP/IP) is the most common protocol used today. A routable protocol, TCP/IP is the protocol on which the internet is built. TCP/IP originally was designed in the 1970s to be used by the Defence Advance Research Projects Agency (DARPA) and the US Department of Defence (DOD) to connect dissimilar systems accross the country. This design recquired the capability to cope with unstable network conditons. Therefore, the design of TCP/IP included the capability to route packects.

             TCP/IP provides end-to-end connectivity specifying how data should be formatted, addressed, transmitted, routed and received at the destination. It has four abstraction layers, each with its own protocols. From lowest to highest, the layers are:

1. The Link (Commonly Ethernet) contain communication technologies for local network.
2. The internet layer (IP) Connect local networks thus establishing internetworking.
3. The Transport Layer (TCP) handles Host-to-Host communications.
4. The application layer (for example HTTP) containsall protocols for specific data communications services on a process-to-process level (for example how a web browser communicate to a web server).

The TCP/IP model and related protocols are maintained by the Internet Engineering  Task Force (IETF).

THE LINK LAYER  The link layer is the networking scope of the local network connection to which a host is attached. This regime is called the link in Internet literature. This is the lowest component layer of the Internet protocols, as TCP/IP is designed to be hardware independent. As a result TCP/IP is able to be implemented on top of virtually any hardware networking technology.

The link layer is used to move packets between the Internet layer interfaces of two different hosts on the same link. The processes of transmitting and receiving packets on a given link can be controlled both in the software device driver for the network card, as well as on firmware or specialized chipsets.

THE INTERNET LAYER: The internet layer has the responsibility of sending packets across potentially multiple networks. Internetworking requires sending data from the source network to the destination network. This process is called routing.

In the Internet protocol suite, the Internet Protocol performs two basic functions:

• Host addressing and identification: This is accomplished with a hierarchical addressing system (see IP address).
• Packet routing: This is the basic task of sending packets of data (datagrams) from source to destination by sending them to the next network node (router) closer to the final destination.

THE TRANSPORT LAYER The transport layer establishes host-to-host connectivity, meaning it handles the details of data transmission that are independent of the structure of user data and the logistics of exchanging information for any particular specific purpose. Its responsibility includes end-to-end message transfer independent of the underlying network, along with error control, segmentation, flow control, congestion control, and application addressing (port numbers). End to end message transmission or connecting applications at the transport layer can be categorized as either connection-oriented, implemented in TCP, or connectionless, implemented in UDP.

THE APPLICATION LAYER: The application layer contains the higher-level protocols used by most applications for network communication. Examples of application layer protocols include the File Transfer Protocol (FTP) and the Simple Mail Transfer Protocol (SMTP). Data coded according to application layer protocols are then encapsulated into one or (occasionally) more transport layer protocols (such as TCP or UDP), which in turn use lower layer protocols to effect actual data transfer.

 

Advantage and Disadvantage of TCP/IP

One of the major advantage of TCP/IP was the fact that it could be used to connect heterogenous (dissimilar) environments together. Which is why it has become the protocol of the internet - but what are its drawbacks? TCP/IP has two major drawbacks.

•  Configuration - TCP/IP is a protocol that recquires configuration, and to administer it, you need to be familiar with IP addresses, Subnet masks, and default gateways. - not complicated topics once you are familiar with them.
• Security - Because of the open design of TCP/IP, it has become a very insecure protocol. If security is of concern, you need to make certain that you inplement additional technologies to secure the network traffic or systems running TCP/IP.

  For example if you want to make sure other individuals cannot read the data sent to your web server, you would SSL enable the website - which would encrypt traffic between a client and your webserver. To know more about security check out network security.