Computer Network-Network Protocols

Network protocols are the sets of rules which govern communication over the network. This works like a stack of protocols in which each protocol uses the one below it. Protocols have signaling, authentication, error detection and correction capabilities. Protocols are of two types in nature, "Connection Oriented" and "connectionless" whether they are on Circuit switching or Packet Switching network. There are many types of network protocols, we will discuss some of them below:

Ethernet:

Ethernet is a family of network protocols mostly used for Local Area Network (LAN). The original 10Base5 Ethernet used coaxial cable as shared medium but later on coaxial cable was replaced with twisted pair and then later fiber optics in conjunction with switches or hubs. Advancement resulted in a periodic increase in data transfer rate from 10 megabits to 100 gigabits per second. Over Ethernet, data packets are divided into small pieces called frame. Each frame contains source address, destination address and error checking data so damaged or lost data can be retransmitted. Ethernet has a sound reputation about its compatibility since its commercial release.

TCP/IP:

TCP/IP, also known as Internet protocol suite is the set of communications protocols used for the Internet and the most popular protocol for wide area networks. TCP/IP is a combination of two networking protocols which are "Transmission Control Protocol (TCP)" and "Internet Protocol (IP)". TCP/IP specifies end-to-end connectivity specifying how data should be formatted, addressed, transmitted, routed and received at the destination. It works on four layer to sort all internet protocols according to the scope of the network. These layers are:

• Link Layer: contains communication technologies for a local area network (LAN).
• Internet Layer (IP): connects local networks to establish inter-networking.
• Transport Layer: responsible for host-to-host communication.
• Application Layer: contains all protocols for specific data communications services on a process-to-process level. For example, HTTP specifies the web browser communication with a web server.

Asynchronous Transfer Mode (ATM):

Asynchronous transfer mode (ATM) is a switching technique for telecommunication networks. It uses asynchronous time-division multiplexing and encodes data into small, fixed-sized pieces called cells. Here it is different from other network protocols such as TCP/IP and Ethernet who uses variable size packets. ATM uses a combination of both Circuit and Packet switching. This makes ATM a good choice for a network that must handle both traditional and real-time, low-latency content such as voice and video. ATM uses connection oriented model which means a virtual connection must be established between two ends before actual communication took place.

SONET/SDH:

Synchronous Optical Networking and Synchronous Digital Hierarchy are multiplexing protocols that transfer multiple digital bit streams over optical fiber. SONET/ SDH was originally standardized for connecting one fiber system to another at the optical level, to form a single international standard for fiber interconnects between telephone networks of different countries. Today it is a widely deployed, mature technology used in implementing high-speed, large-scale IP networks. It combines high bandwidth capacity with efficient link utilization, making it a major building block for accommodating fast-growing IP infrastructure both in the core and at the edge. Due to its protocol neutrality and transport-oriented features, SONET/SDH also was the obvious choice for transporting Asynchronous Transfer Mode (ATM) frames.