Network Protocols

Data that is being sent between computers is car­ried in the data field of the Ethernet frame and structured as high-level network protocols. The high-level network protocol information carried inside the data field of each Ethernet frame is what actually establishes communications between appli­cations running on computers attached to the network. The most widely used sys­tem of high-level network protocols is called the Transmission Control Protocol/ Internet Protocol (TCP/IP) suite.

The important thing to understand is that the high-level protocols are indepen­dent of the Ethernet system. There are several network protocols in use today, any of which may send data between computers in the data field of an Ethernet frame. In essence, an Ethernet LAN with its hardware and Ethernet frame is simply a trucking service for data being sent by applications. The Ethernet LAN itself doesn't know or care about the high-level protocol data being carried in the data field of the Ethernet frame.

Since the Ethernet system is unaffected by the contents of the data field in the frame, different sets of computers running different high-level network protocols can share the same Ethernet. For example, you can have a single Ethernet that supports four computers, two of which communicate using TCP/IP, and two that use some other system of high-level protocols. All four computers can send Ether­net frames over the same Ethernet system without any problem.

Design of Network Protocols

Network protocols are easy to understand since we all use some form of protocol in daily life. A network protocol acts much like the letter protocol described above. To carry data between applications, the network software on your computer creates and sends a network protocol packet with its own private data field that corresponds to the message of the letter. The sender's and recipient's names (or protocol addresses) arc added to complete the packet. After the network software has cre­ated the packet, the entire network protocol packet is stuffed into the data field of an Ethernet frame. Next, the 48-bit destination and source addresses arc provided, and the frame is handed to the Ethernet interface and the Ethernet signal and cabling system for delivery to the right computer.

Ethernet frame is then placed on the Ethernet media system for delivery to Station 15.

Questionnaire:

• Explain about the Network protocols?