In this tutorial, we’ll discuss a popular wireless networking protocol that allows multiple devices to access the network simultaneously without causing interference or collisions: Multiple Access with Collision Avoidance (MACA).
Finally, we’ll spotlight the crucial advantages and disadvantages of this protocol.
2. Basic Idea
We generally use Multiple Access with Collision Avoidance (MACA) protocol in computer networks that allows multiple devices to access a shared communication medium without colliding. Additionally, MACA is a variant of Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA), which is a protocol frequently employed in wireless networks.
In MACA, a device that intends to transmit data monitors the communication channel. The aim is to determine whether the communication medium is busy or not. Additionally, a device does such sensing of a medium for a predetermined period of time. If the medium is idle, the device can start transmitting its data. However, if the medium is busy, the device waits until it’s free before transmitting.
Furthermore, MACA utilizes Request to Send (RTS) and Clear to Send (CTS) mechanisms to prevent collisions. Before a device transmits data, it sends an RTS packet to request permission to transmit. If the receiving device is free to receive data, it responds with a CTS packet. If the sender receives a CTS packet from the receiver, the receiver is ready to receive the data. Hence, the transmitting device can then proceed with the data transmission.
Hence, the use of RTS and CTS packets helps to avoid collisions by ensuring that multiple devices don’t try to transmit data simultaneously. Additionally, the MACA protocol is especially useful in wireless networks. In wireless, the communication medium is shared among multiple devices. Additionally, due to the sharing nature and wireless signal propagation, collisions are common in wireless.
Here are the steps involved in MACA:
The first step is to sense the medium. Before transmitting data, the device senses the medium to check if it is busy or idle. Additionally, if the medium is busy, the device waits for it to become idle before transmitting.
As soon as the sender realizes the communication medium is free, the sender starts preparing for the transmission. Furthermore, the device that wants to transmit data sends an RTS packet to the receiving device to request permission.
Now at this point, it’s essential to determine that the receiving device is ready to receive the data. Additionally, the receiving device may be already engaged in data transmission with other devices. When the receiving device is prepared to accept data, it transmits a CTS packet to signal its readiness to the sender. Once the transmitting device receives the CTS packet, it can start transmitting data to the receiving device.
After the data transmission is complete, the receiving device sends an acknowledgment (ACK) packet to acknowledge the receipt of the data.
Now let’s talk about a situation where there’s a collision. Such a situation occurs when the transmitting device doesn’t receive a CTS packet in response to the RTS packet. Therefore, the sender assumes that there’s a collision with another device and waits for a random period of time before retrying the transmission.
These steps are repeated for every data transmission in the network, ensuring that multiple devices can share the communication medium without colliding with each other. Additionally, MACA is a popular technique in wireless networking as it mitigates collisions and enhances the effectiveness of data transmission.
4. Advantages and Disadvantages
Let’s talk about the advantages and disadvantages of MACA:
In this tutorial, we discussed Multiple Access with Collision Avoidance (MACA) protocol. Furthermore, we explored the steps involved in this protocol. Finally, we listed the major advantages as well as disadvantages of this protocol.