Multiple Access Protocols

Understanding protocols for shared channel access in networks

Introduction to Multiple Access

Multiple Access Protocols are methods that allow multiple devices to share a common communication channel efficiently. These protocols are essential in network environments where multiple users need to access the same transmission medium.

Types of Multiple Access Protocols

Random Access Protocols

No centralized control:

ALOHA
CSMA (Carrier Sense Multiple Access)
CSMA/CD (Collision Detection)
CSMA/CA (Collision Avoidance)

Controlled Access Protocols

Centralized or distributed control:

Reservation
Polling
Token Passing
Time Division Multiple Access (TDMA)

Channelization Protocols

Dividing channel capacity:

Frequency Division Multiple Access (FDMA)
Time Division Multiple Access (TDMA)
Code Division Multiple Access (CDMA)
Orthogonal Frequency Division Multiple Access (OFDMA)

Common Protocols in Detail

CSMA/CD

Used in Ethernet networks:

Listen before transmit
Detect collisions
Back off and retry
Binary exponential backoff

CSMA/CA

Used in wireless networks:

Virtual carrier sensing
RTS/CTS mechanism
Collision avoidance
Priority-based access

Comparison of Protocols

Protocol Type	Advantages	Disadvantages	Applications
Random Access	Simple, No overhead	Collisions possible	Ethernet, WiFi
Controlled Access	No collisions	Overhead, Delay	Token Ring, Polling
Channelization	Efficient, No collisions	Complex, Fixed allocation	Cellular, Satellite

Multiple Access का परिचय

Multiple Access Protocols वे methods हैं जो multiple devices को एक common communication channel को efficiently share करने की अनुमति देते हैं। ये protocols network environments में essential हैं जहां multiple users को एक ही transmission medium का access चाहिए।