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? Cache Server What Is WSN Network? Check Sum Error Detection Linear Bus Topology Functions of the Transport Layer Infrared Transmission in Computer Networks Digital Signal in Computer Network Digital Data Transmission in Computer Networks Define Checksum with Example Computer Network Security Requirements Brust Errors in Computer Network Back Side Bus (BSB) 2-Dimension Parity Check in Computer Network Router and Brouter Microwave Transmission in Computer Networks Magnetic Media in Computer Network A One-Bit Sliding Window Protocol CDMA-Near-Far Problem Reference Models in Computer Networks Uni-cast, Broadcast, and Multicast in Computer Networks Uses Of Bridges in Computer Networks What are Gateways in Computer Network?

IEEE 802.15.4 Technology


Low-cost, low-data-rate wireless access technology for battery-operated devices is IEEE 802.15.4. This explains the operation of low-rate wireless personal area networks or LR-WPANs.

IEEE 802.15.4e: 

IEEE 802.15.4e enhances the standard by introducing features such as channel hopping, multichannel communication, and time-slotted access, aimed at improving network efficiency and versatility.

The following general functional enhancements are introduced by IEEE 802.15.4e:

 1. Low Energy (LE): Applications able to exchange latency for energy efficiency are the target audience for this technique. It allows a node to run at an extremely low-duty cycle.

2. Elements of Information (IE): At the MAC sublayer, it is an extendable framework for information sharing.

3. Enhanced Beacons (EB): Offering more versatility, Enhanced Beacons expand the 802.15.4 beacon frames. Making application-specific frames is possible with them.

4. Multipurpose Frame: This mechanism offers an adaptable frame format that can handle various MAC functions. It is predicated on Internet Explorers.

5. MAC Performance Metric: This is a way to give networking and higher layers the proper input on the channel quality to make the right decisions.

6. Rapid Assemblies (RapidA): The 802.15.4 association mechanism adds a substantial delay to preserve energy. Energy efficiency is secondary to latency for applications that must be completed on time.

IEEE 802.15.4e has five additional MAC behaviour modes defined:

IEEE 802.15.4e defines five additional MAC behavior modes, including Time Slotted Channel Hopping (TSCH), DSME, LLDN, BLINK, and AMCA, catering to diverse application domains such as industrial automation, process control, tracking, and infrastructure monitoring.

1. Time Slotted Channel Hopping (TSCH): Using a TDMA technique, it supports multi-hop and multichannel communications and is aimed at application domains, including industrial automation and process control.

2. DSME: The goal of Deterministic and Synchronous Multi-channel Extension (DSME) is to facilitate the use of DSME in commercial and industrial settings.

 3. LLDN: Single-hop and single-channel networks are the target audience for the Low Latency Deterministic Network (LLDN).

 4. Identification of Radio Frequencies Blink (BLINK): It is designed for application domains like tracking, location, and item/person identification.

 5. Asynchronous multi-channel adaptation (AMCA): This technology is intended for application domains like process control, infrastructure monitoring, and smart utility networks where extensive deployments are necessary.


1. Alliances and standardization: It outlines the MAC layer and low-data-rate PHY specifications for wireless personal area networks (WPAN).

IEEE 802.15 - List of Protocol Stacks:

ZigBee: ZigBee is a low rate task group 4 Personal Area Network task group. It's a home networking technology. A technology standard called ZigBee was developed for network sensing and control. Since ZigBee is the Personal Area network of Task Group 4, it was developed by the Zigbee Alliance and is based on IEEE 802.15.4.

6LoWPAN: Wireless sensor networks are among the many uses for the 6LoWPAN architecture. IPv6 over Low power Wireless Personal Area Networks is the moniker given to this type of wireless sensor network, which uses IPv6 and transmits data in packets.

ZigBee IP: Designed for low-cost and low-power wireless machine-to-machine (M2M) and internet of things (IoT) networks, Zigbee is a standards-based wireless technology.

ISA100.11a: This mesh network offers process control users safe wireless connectivity.

Wireless HART: Another wireless sensor network technique that uses self-organizing and time-synchronized architecture is called wireless HART.

Thread: Thread is an IEEE 802.15 wireless mesh network's IPv6-based networking technology for low-power Internet of Things devices. Each thread is autonomous.

2. Physical Layer: A variety of PHY alternatives in ISM bands, from 2.4 GHz to sub-GHz frequencies, are made possible by this standard. Data transfer rates of 20 kilobits per second, 40 kilobits per second, 100 kilobits per second, and 250 kilobits per second are made possible by IEEE 802.15.4. The basic design makes the assumption that the distance is 10 meters and the data rate is 250 kilobits per second. Even lower data rates are feasible in order to further minimize power consumption. At the physical layer, IEEE 802.15.4 controls the RF transceiver, channel selection, and even a few aspects of energy and signal management. Six PHYs are now specified based on the required data throughput and frequency range. Direct Sequence Spread Spectrum (DSSS) frequency hopping techniques are used by four of them. To preserve a shared, basic interface with MAC, the PHY data service and management service use a single packet structure.

3. MAC layer: By finding out which devices in the same area will share the allocated frequencies, the MAC layer establishes a connection to the PHY channel. This layer is also responsible for managing packet scheduling and routing. The 802.15.4 MAC layer is in charge of many functions, including:

  • beaconing for hardware used in a network as controllers.
  • utilized to employ devices to associate and disassociate PANs.
  • the device's safety.
  • reliable communication in a peer-to-peer link between two MAC devices.

The MAC layer performs these tasks using a number of recognized frame types. There are four distinct MAC frame types in 802.15.4:

  • data frame
  • Beacon frame
  • Structure of Recognition
  • Structure for MAC directives

4. Topology: IEEE 802.15.4-based networks can be designed with a mesh, peer-to-peer, or star topology. Numerous nodes are connected using mesh networks. This allows nodes that would not normally be able to communicate with one another to employ intermediary nodes as a means of data relaying.

5. Security: The IEEE 802.15.4 standard uses the Advanced Encryption Standard (AES) as the foundational encryption method, with a 128-bit key length. Enabling these security protocols for 802.15.4 modifies the frame format considerably and utilizes some of the payloads. The Security Enabled field in the Frame Control section of the 802.15.4 header must be used in order to initiate AES encryption. This field is a single bit that is assigned to 1 for safety's sake. When this bit is set, the Source Address field is followed by a field called the Auxiliary Security Header, which is created by extracting specific bytes from the Payload field.

6. Competitive Technologies: Different networking profiles that function in various IoT access scenarios are based on the IEEE 802.15.4 PHY and MAC layers. A rival radio system that has different MAC and PHY layers is called DASH7.

The benefits of IEEE 802.15.4

  • Inexpensive
  • long-lasting battery
  • easy to install
  • simple
  • extensible protocol stack

Drawback of IEEE 802.15.4

  • Multipath fading and interference are caused by IEEE 802.15.4.
  • does not use a frequency-hopping strategy.
  • Unlimited latency sensitivity to interference

The uses of IEEE 802.15.4

  • Wireless sensor networks in industries.
  • Automation of buildings and homes
  • Playthings that interact and remote controls
  • Vehicle networks