Computer Network Tutorial

Introduction of Computer Network Types of Computer Network Network Topology Computer Networking Architecture Transmission Modes (Data Flow) Basic Networking Devices Integrate Services Digital Network (ISDN)


OSI Model TCP/IP Model

Physical Layer

Digital Transmission Analog Transmission Transmission Media Switching

Data Link Layer

Error detection and Error correction Data Link Control Multiple Access Aloha

Network Layer

Network Layer - Logical Address Address Mapping Unicast Routing Protocol

Transport Layer

Process to Process Delivery User Datagram Protocol Transmission Control Protocol Stream Control Transmission Protocol Session Layer and Presentation Layer

Application Layer

Domain Name System Application Protocol E-mail Cryptography


Classes of Routing Protocols Classification of Routing Algorithms Controlled Access Protocols in Computer Networks Differences between IPv4 and IPv6 Fixed and Flooding Routing Algorithms Advantages and Disadvantages of Fibre Optics Cable APIPA Difference between Active and Passive FTP Fiber Optics and its Types Method of Joining and Fusion of Fiber Optic Cable Define Framing in Computer Network Disadvantages of Computer Network Mesh Topology Diagram in Computer Network Ring Topology in Computer Network Star Topology in Computer Networks 4G Mobile Communication Technology Advantages and Disadvantages of LAN Advantages and Disadvantages of MAN Advantages and Disadvantages of WAN Application Layer in OSI Model Cyclic Redundancy Check Example Data link layer in OSI model Difference between Transport and Network Layer Hamming Code Example Network Layer in OSI Model Session Layer in OSI Model Transport Layer in OSI Model Two Port Network in Computer Networks Uses of Computer Networks What is Computer Network What is Framing in a Computer Network Advantages and Disadvantages of Bus Topology Difference between Star Topology and Bus Topology Subnetting in Computer Network Subnetting Questions and Answers What is Bus Topology What is Network Topology and Types in Computer Networks Access Control in Networking Basic Characteristics of Computer Network Benefits of SOCKS5 Proxy in Computer Networks Computer Network viva Questions Difference between BOOTP and RARP Difference Between Network Topologies and Network Protocols Difference between NFC and RFID Difference Between Point-to-Point Link and star Topology Network Differences Between MSS and MTU Differences Between Trunk Port and Access Port Different Modes of Communication in Computer Networks MIME Protocol in Computer Networks Modes of Communication in Computer Networks Network Attack in Computer Network Port Address in Networking Simplest Protocol in Computer Network Sliding Window Protocol in Computer Network Stop And Wait Protocol in Computer Networks TCP 3-Way Handshake Process in Computer Networks What is a Proxy Server What is APPN What is ICMP Protocol What is Point-to-Point Protocol What is Port Address in Networking What is the HDLC Protocol What is VRRP Protocol Difference Between Analog and Digital Signals Difference Between Hub and Repeater Difference between Repeater and Switch Difference Between Transparent Bridge and Source Routing Bridge Source Routing Bridge in Computer Networks Transparent Bridge in Computer Networks Transport Protocol in Computer Networks Types of CSMA in Computer Networks What is Wired and Wireless Networking Network Security in Computer Network Disadvantages of Extranet Difference Between TELNET and FTP Define Protocol in Computer Networks Guided Transmission Media in Computer Network What is a Gateway in a Computer Network IGMP in Computer Networks LAN Protocols in Computer Networks MAN Meaning in Computer Modulation Techniques in Computer Networks Switching in DCN TCP/IP Applications What is IGMP? What is Modem in Networking What is Non-Persistent CSMA Difference between Cell Splitting and Cell Sectoring Forouzen Computer Network Open Loop and Closed Loop Congestion Control Types of Cluster Computing WAP-Wireless Access Point What are the elements of the Transport Protocol Difference between Gateway and Switch Flow Control in Data Link Layer Body Area Network Flooding in Computer Network Token Ring in Computer Networks VoIP in Computer Networks What is Infrared Transmission Congestion Control Techniques Forward Error Correction (FEC) Switching Techniques What is Telnet in Computer Network What are the Types of IPv4 Addresses IEEE 802.6 (DQDB) IEEE 802.15.4 Technology What is HDLC (High-level Data Link Control)? What is SMS Hubbing in Telecom? Circuit Switching in Computer Networks Communication Satellites in Computer Networks Features of HTTP Protocol IMAP4 (Internet Message Access Protocol) Internet Services How to Set up a Wireless Router Internetwork Routing in Computer Networks Distributed Computing System Features of GSM The 802.11 MAC Sublayer Protocol What is IEEE 802.3? What are Hubs and Switches in Computer Networks? What is Modem in a Computer Network? What is multicasting in Computer Networks? GSM -The Mobile Station What is Network Server? Slotted Aloha in Computer Network What is Ethernet in Computer Networks What is Arpanet? Radio Access Network (RAN) TCP 3-Way Handshake Process PING SWEEP (ICMP SWEEP) Print Server Private IP Address Security Services in Computer Networks Protocol Data Unit (PDU) CSMA with Collision Avoidance (CSMA/CA) What is Gateway in Computer Network? Advantages of Networking Data Link Layer Design Issues DHCP in Computer Networks Internet Security Association and Key Management Protocol (ISAKMP) What is Switch Hub? Telnet Full form in Networking Multimedia Systems Quality of Service in Computer Networks What is Carrier Sense Multiple Access (CSMA)? What is Circuit Switching What is Duplex Network? What is Web Protocol Network LAN Technologies Classes in Computer Network Low-Density Parity Check (LDPC) Wireless Internet Service Providers(Wisps) What is Handshaking?

What is IEEE 802.3?

Ethernet technologies are mainly utilized in LANs. For wire Ethernet networks, IEEE 802.3 specifies the physical layer and the data link layer's medium access management (MAC) sub-layer. Ethernet-based networks are defined by the requirements and methods included in IEEE 802.3. Although they can also be employed in the MANs and even WANs,LANs are the main application for the set of protocols and systems known as Ethernet. The IEEE 802.3 standard initially codified it in the 1980s. For wired Ethernet connections, IEEE 802.3 specifies the physical layer and the data link layer's media access control (MAC) sub-layer. There are two types of Ethernet: switching Ethernet and traditional Ethernet.

The first version of Ethernet, known as classical Ethernet, had data speeds ranging from 3 to 10 Mbps. The variants are known as 10BASE-X in common parlance. In this case, the maximum throughput is 10, or 10 Mbps. BASE stands for baseband transmission, and X indicates the kind of media that is being used. Most of the original Ethernet variants are no longer relevant in the current communication environment. A switching Ethernet uses switches to establish connections with LAN stations. It enables complete bandwidth usage and replaces the repeaters required in traditional Ethernet.

IEEE 802.3 Popular Versions

The IEEE 802.3 protocol exists in several variants. The most well-liked ones are:

What is IEEE 802.3?
  1. IEEE 802.3: This was the 10BASE-5 protocol originally provided. It used a substantial single coaxial cable with a connector made by cutting into the cable to the centre. Here, BASE stands for base delivery, 5 is the maximum segment length of 500 meters, and 10 is the maximum productivity or 10 Mbps.
  2. IEEE 802.3a provided the 10BASE-2 norm for thin coax, a thinner type in which BNC connections join coaxial cable segments. The two denote a maximum section length of 185 or roughly 200 meters.
  3. IEEE 802.3i: This provided the twisted couple (10BASE-T) standard, which employs copper wires that are unshielded twisted pair (UTP) as the actual physical layer medium. IEEE 802.3u provided more versions for 100BASE-TX, 100BASE-T4, and 100BASE-FX.
  4. IEEE 802.3j: This provided the 10BASE-F Internet over Fibre accepted, which employs optical cables as the communication medium.

Frame Format of Classic Ethernet and IEEE 802.3

A traditional Ethernet frame's primary fields are:

What is IEEE 802.3?

A traditional Ethernet frame's primary fields are:

  • Preamble: An Ethernet frame begins with a preamble of seven bytes. This alternate sequence of 0s and 1s denotes the beginning of the frame and permits bit synchronization between the message's sender and the recipient. To accommodate for the loss of a few bits owing to transmission delays, PRE (Preamble) was first devised. Preamble, however, is no longer necessary for protecting the frame bits in fast speeds Ethernet. The PRE (Preamble) lets the receiver lock on the data stream before the start of the frame by notifying it of its impending arrival.
  • Beginning of Frame Delimiter: The Beginning of Frame Delimiter (SFD) is a 1-byte field with a constant value of 10101011, indicating the imminent start of the frame. The preamble is frequently stated as 8 Bytes since SFD is occasionally regarded as a component of PRE. This is the final opportunity for timing, the SFD alerts to the station or stations.
  • Destination Address: The actual location of the final station stations is contained in a 6-byte field.
  • Source Address: The transmitting station's location is in a 6-byte field.
  • Length: The total amount of pixels in the information field is stored in a 7-bit field.
  • Data: This is the payload—the actual data—placed here. If the Internet Protocol is utilized over Ethernet, the IP address and the data will be placed here. Up to 1500 Bytes can be the maximum amount of present data. The padding 0s are added to the data if its length is less than the least, which is 46 bytes, to make it as short as feasible.
  • Padding: The data is cushioned to meet the minimum necessary length of 46 bytes.
  • CRC: A 4-byte field is the CRC. A 32-bit hashing algorithm of the data is contained in this field and created using the data, length, source address, and destination addresses. Data retrieved is damaged if the destination's computed checksum differs from the provided checksum value.
  • Virtual Local Area Network (VLAN) tags :VLAN tags, consisting of 4-byte fields, are inserted into an Ethernet frame after the original address and the EtherType field. With this tag, network managers can logically divide an actual network into several simulated networks, each with a unique VLAN ID.
  • Jumbo Frames: Some network equipment enables frames with a payload bigger than 1500 bytes, known as Jumbo Frames, and the usual Ethernet frame size of 1518. Jumbo Frames lower the cost of sending many small frames at once, which can boost networking performance.
  • Ether Type Field: The protocol carried within a message's payload is identified by the EtherType field in the frame's Ethernet header. For instance, a payload of IP packets is indicated by a value of 0x0800, whereas an ARP (Address Resolution Protocol) packet is indicated by a quantity of 0x0806.
  • Multicast and Broadcast Frames: Ethernet supports Multicast and Broadcast messages alongside Unicast frames, which target specific destinations based on MAC addresses. Broadcasting frames are transmitted to every device on the network at once, whereas multicast messages are distributed to a particular set of machines that are part of a broadcast group.
  • Collision Detection: A collision may happen when multiple devices try to send data simultaneously across half-duplex Ethernet connections. Ethernet employs the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol, which stops data transmission in the event of an incident and waits for network activity to resume before starting data transmission.


  • Simple format: Ethernet connections are simple to establish and debug due to the frame format's simplicity and ease of understanding.
  • Flexibility: Its Ethernet frame format is adaptable to various connection topologies and data sizes, making it appropriate for a wide variety of network-related tasks.
  • Adopted widely: Many suppliers and network devices support the Ethernet frame format, guaranteeing interoperability and compatibility.
  • Error detection: To assist in guaranteeing the confidentiality of information during transmission, the Ethernet frame structure incorporates a check for cyclic redundancy (CRC) field for identifying errors.
  • Virtual local area networks (VLANs)  enable network managers to logically divide a real LAN into several smaller virtual LANs for better network administration and safety, supported by the Ethernet cable format.


  • Restricted frame size: The biggest frame size allowed by the Ethernet packet format is 1500 bytes. This might limit the data sent in a single frame and raise overhead because bigger packets must be fragmented and reassembled.
  • Broadcast storms: Broadcast storms can occur when excess devices send broadcasting frames simultaneously, causing network traffic jams and performance problems. Ethernet connections use broadcasting broadcasts to send images to every device on the network.
  • Security errors: Because the Ethernet frame format lacks intrinsic security protections, wiretapping and spoofing are two common security risks that affect Ethernet networks.
  • Limited speed: the maximum speed of Ethernet connections is constrained, making it insufficient for networks of immense size or applications that require rapid speeds.
  • Restricted distance: An Internet network's actual coverage may be restricted by the greatest distance that two endpoints can be distanced together.