• Skip to main content
  • Skip to primary sidebar
  • Skip to secondary sidebar
  • Skip to footer

Computer Notes

Library
    • Computer Fundamental
    • Computer Memory
    • DBMS Tutorial
    • Operating System
    • Computer Networking
    • C Programming
    • C++ Programming
    • Java Programming
    • C# Programming
    • SQL Tutorial
    • Management Tutorial
    • Computer Graphics
    • Compiler Design
    • Style Sheet
    • JavaScript Tutorial
    • Html Tutorial
    • Wordpress Tutorial
    • Python Tutorial
    • PHP Tutorial
    • JSP Tutorial
    • AngularJS Tutorial
    • Data Structures
    • E Commerce Tutorial
    • Visual Basic
    • Structs2 Tutorial
    • Digital Electronics
    • Internet Terms
    • Servlet Tutorial
    • Software Engineering
    • Interviews Questions
    • Basic Terms
    • Troubleshooting
Menu

Header Right

Home » Networking » Access » Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)
Next →
← Prev

Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)

By Dinesh Thakur

• CSMA/CA protocol is used in wireless networks because they cannot detect the collision so the only solution is collision avoidance.

• CSMA/CA avoids the collisions using three basic techniques.

(i) Interframe space

(ii) Contention window

(iii) Acknowledgements

CSMA/CA

1. Interframe Space (IFS)

• Whenever the channel is found idle, the station does not transmit immediately. It waits for a period of time called interframe space (IFS).

• When channel is sensed to be idle, it may be possible that same distant station may have already started transmitting and the signal of that distant station has not yet reached other stations.

• Therefore the purpose of IFS time is to allow this transmitted signal to reach other stations.

• If after this IFS time, the channel is still idle, the station can send, but it still needs to wait a time equal to contention time.

• IFS variable can also be used to define the priority of a station or a frame.

We’ll be covering the following topics in this tutorial:

  • 2. Contention Window 
  • 3. Acknowledgement  
  • CSMA/CA Procedure:

2. Contention Window 

• Contention window is an amount of time divided into slots.

• A station that is ready to send chooses a random number of slots as its wait time.

• The number of slots in the window changes according to the binary exponential back-off strategy. It means that it is set of one slot the first time and then doubles each time the station cannot detect an idle channel after the IFS time.

• This is very similar to the p-persistent method except that a random outcome defines the number of slots taken by the waiting station.

• In contention window the station needs to sense the channel after each time slot.

• If the station finds the channel busy, it does not restart the process. It just stops the timer & restarts it when the channel is sensed as idle.

3. Acknowledgement  

• Despite all the precautions, collisions may occur and destroy the data.

• The positive acknowledgment and the time-out timer can help guarantee that receiver has received the frame.

CSMA/CA Procedure:

Fig. Shows the flow chart explaining the principle of CSMA/CA.

CSMA/CA Procedure

• This is the CSMA protocol with collision avoidance.

• The station ready to transmit, senses the line by using one of the persistent strategies.

• As soon as it find the line to be idle, the station waits for an IFG (Interframe gap) amount of time.

• If then waits for some random time and sends the frame.

• After sending the frame, it sets a timer and waits for the acknowledgement from the receiver.

• If the acknowledgement is received before expiry of the timer, then the transmission is successful.

• But if the transmitting station does not receive the expected acknowledgement before the timer expiry then it increments the back off parameter, waits for the back off time and resenses the line.

You’ll also like:

  1. Carrier Sense Multiple Access with Collision Detection (CSMA/CD)
  2. Carrier Sense Multiple Access (CSMA)
  3. Frequency Division Multiple Access (FDMA).
  4. Time Division Multiple Access (TDMA).
  5. Code Division Multiple Access (CDMA).
Next →
← Prev
Like/Subscribe us for latest updates     

About Dinesh Thakur
Dinesh ThakurDinesh Thakur holds an B.C.A, MCDBA, MCSD certifications. Dinesh authors the hugely popular Computer Notes blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps.

Dinesh Thakur is a Freelance Writer who helps different clients from all over the globe. Dinesh has written over 500+ blogs, 30+ eBooks, and 10000+ Posts for all types of clients.


For any type of query or something that you think is missing, please feel free to Contact us.


Primary Sidebar

Networking

Networking Tutorials

  • Network - Home
  • Network - Uses
  • Network - Advantages
  • Network - Classification
  • Network - Architecture Type
  • Nework - Networks Vs Comms

Networking Devices

  • Network - Modem
  • Network - Routers Types
  • Network - Bluetooth
  • Network - RS-232C
  • Network - Hub
  • Network - Devices
  • Network - Bridges
  • Network - Repeaters
  • Network - Routers
  • Network - Switching Hubs
  • Network - Transceiver
  • Network - Multiplexer
  • Network - Gateway
  • Network - BNC Connector
  • Network - Optical Connectors
  • Network - NICs
  • Networking Protocol

  • Protocol - Definition
  • Protocol - IP
  • Protocol - Aloha
  • Protocol - MAC Layer
  • Protocol - Sliding Window
  • Protocol - Stop & Wait
  • Protocol - Network Protocols
  • Protocol - Token Passing
  • Protocol - SIP
  • Protocol - Ad-Hoc Networks Routing
  • Protocol - Lap-f
  • Protocol - Point-to-Point
  • Protocol - PPP
  • Protocol - PPP Phases
  • Protocol - LDP
  • Protocol - MPLS
  • Protocol - MPOA
  • Protocol - HDLC
  • Protocol - Distance Vector routing
  • Protocol - IGMP
  • Protocol - ICMP
  • Protocol - SLIP
  • Protocol - DVMRP
  • Protocol - SDLC
  • Protocol - Routing
  • Protocol - UDP
  • Protocol - ARP and RARP
  • Protocol - Link-State
  • Protocol - ARP Table
  • Protocol - RTP
  • Protocol - NHRP
  • Network Addressing

  • Addressing - Home
  • Addressing - SubNetting
  • Addressing - Classless
  • Addressing - Classes or Classful
  • Addressing - IPV4 vs IPV6
  • Addressing - IPv6
  • Addressing - Subnet Mask
  • Addressing - MAC Address
  • Addressing - Supernetting
  • Addressing - Private IP
  • Addressing - IPv4
  • Addressing - Public IP
  • Addressing - Multihomed
  • Addressing - Indirect Addressing
  • Addressing - ASP
  • Addressing - VLSM
  • Addressing - Routing Algorithms
  • Addressing - Hierarchical Routing
  • Addressing - Routing
  • Addressing - Distributed Routing
  • Addressing - Data Routing
  • Addressing - Services
  • Addressing - IP forwarding
  • Addressing - Aging
  • Addressing - Algorithm CR
  • Networking Media

  • Transmission - Home
  • Transmission - Modes
  • Transmission - Media
  • Transmission - System
  • Transmission - Bound
  • Transmission - Unbound
  • Transmission - Baseband
  • Transmission - Wired
  • Transmission - Fiber Benfits
  • Transmission - Infrared
  • Transmission - UnGuided
  • Transmission - Microwave
  • Transmission - Infrared
  • Transmission - Radio Wave
  • Transmission - Network
  • Transmission - Digital Signal
  • Transmission - Data
  • Transmission - Asynchronous
  • Transmission - Sync Vs Async
  • Cable - Twisted-Pair
  • Cable - Coaxial
  • Cable - UTP and STP
  • Cable - Fiber Optics
  • Cable - Gigabit Ethernet
  • Cable - Fast Ethernet
  • Cable - Ethernet Cable
  • Cable - Fiber-Optic Using
  • Cable - CATV
  • Cable - 100Base T
  • Cable - 10BASE T
  • Cable - 10 Base 2
  • Cable - 10 Base 5
  • Networking Types

  • IEEE - 802.11
  • IEEE - 802.5
  • IEEE - 802.15
  • IEEE - 802.11e
  • IEEE - 802.11n
  • Network - Ethernet
  • Network - Arpanet
  • Network - Frame Relay
  • Network - X.25
  • Network - Telephone
  • Network - WSN
  • Network - Metro Ethernet
  • Network - WAN Ethernet
  • Network - Wireless Mesh
  • Network - SAN
  • Network - SNA
  • Network - Cisco Architecture
  • Network - Vlan
  • Network - FDDI
  • Network - 100VG-Any
  • Network - EPON
  • Network - ISDN
  • Network - ARCNet
  • Network - Passive Optical
  • Networking Reference Models

  • Models - TCP/IP
  • Models - OSI
  • Models - MAC Layer
  • Models - Network Layer
  • Models - MAC Layer Functions
  • Models - TCP/IP Vs OSI
  • Models - CSMA
  • Models - CSMA/CD
  • Models - CSMA/CA
  • Models - CDMA
  • Models - STDM
  • Models - FDMA
  • Models - TDMA
  • Models - SDH
  • Models - CDM
  • Models - Multiplexing
  • Models - Reference
  • Models - Random Access Methods
  • Models - TCP/IP Architecture
  • Models - FDM
  • Models - IP Header
  • Models - OTN
  • Models - Amplitude Levels
  • Models - MIMO
  • Models - Plesiochronous Media
  • Models - Half Duplex
  • Models - ISO Architecture
  • Models - Data-Link Layer
  • Models - WDM
  • Models - Duplex
  • Models - Ethernet FDSE
  • Networking Switching Techniques

  • Switching - Home
  • Switching - Techniques
  • Switching - Packet
  • Switching - Circuit
  • Switching - Message
  • Switching - Packet Vs virtual Circuit
  • Switching - Cell
  • Switching - ATM Cell Structure
  • Switching - Virtual Circuit Vs Datagram
  • Switching - Time Space
  • Switching - Modulation
  • Switching - Cell Relay
  • Switching - ATM Structure
  • Switching - VC Vs PVC
  • Switching - Packet and Circuit
  • Switching - VPC
  • Switching - IP
  • Switching - Logical Channels
  • Switching - TDM
  • Switching - FDM
  • Network Codes

  • Codes - CRC
  • Codes - Error Correction and Detection
  • Codes - Hamming
  • Codes - Piggybacking
  • Codes - Encoding Techniques
  • Codes - Error Control
  • Codes - Parity Check
  • Codes - Parity bit
  • Codes - Bit Error
  • Codes - CRC
  • Codes - Transmission Errors
  • Codes - Error Detection and Correction
  • Network Communication

  • Communication - Home
  • Communication - Satellite
  • Communication - Wireless
  • Communication - Data Type
  • Communication - Congestion Control
  • Communication - Network
  • Communication - Data
  • Communication - Software
  • Communication - Layering Process
  • Networking Signaling

  • Signal - Analog
  • Signal - Digital
  • Signal - Analog Vs Digital
  • Signal - Digitization
  • Network Security

  • Security - Home
  • Security - Requirements
  • Security - Threats
  • Security - Services

Other Links

  • Networking - PDF Version

Footer

Basic Course

  • Computer Fundamental
  • Computer Networking
  • Operating System
  • Database System
  • Computer Graphics
  • Management System
  • Software Engineering
  • Digital Electronics
  • Electronic Commerce
  • Compiler Design
  • Troubleshooting

Programming

  • Java Programming
  • Structured Query (SQL)
  • C Programming
  • C++ Programming
  • Visual Basic
  • Data Structures
  • Struts 2
  • Java Servlet
  • C# Programming
  • Basic Terms
  • Interviews

World Wide Web

  • Internet
  • Java Script
  • HTML Language
  • Cascading Style Sheet
  • Java Server Pages
  • Wordpress
  • PHP
  • Python Tutorial
  • AngularJS
  • Troubleshooting

 About Us |  Contact Us |  FAQ

Dinesh Thakur is a Technology Columinist and founder of Computer Notes.

Copyright © 2023. All Rights Reserved.