Question

A group of friends gets togcther to play highly interactive CPU- and network- intensive video games. The friends play together using a high-bandwidth wireless network. The wireless signal cannot propagate through walls, but the friends are all in the same room. In such a setup, would it be best to use nonpersistent CSMA or the token ring protocol? Please explain you answer.

Short answer

The token ring protocol is better as it minimizes latency and avoids collisions, which is crucial for gaming.

Step-by-step solution

Understanding the Nonpersistent CSMA Protocol

In a nonpersistent CSMA (Carrier Sense Multiple Access) protocol, devices check if the communication medium is free before sending data. If the medium is busy, they wait for a random time before checking again. This can lead to collisions when multiple devices try to send data simultaneously once the medium becomes free, causing delays in high traffic scenarios.

Understanding the Token Ring Protocol

In a token ring protocol, a token circulates among the devices. Only the device holding the token can send data, virtually eliminating the chances of collisions. This protocol ensures a fair and predictable access to the network, making it suitable for real-time gaming where latency and synchronization are critical.

Comparing the Protocols for Gaming Needs

For highly interactive and network-intensive gaming, minimizing latency and avoiding collisions is crucial. Nonpersistent CSMA might introduce random delays due to collisions and random back-off periods, which are undesirable in gaming. In contrast, the token ring protocol ensures orderly access and minimizes delays, providing more stable performance.

Choosing the Best Protocol

Given the need for low latency and reliable communication in gaming where all friends are in the same room, the token ring protocol is preferable. It provides controlled access and predictable delays, enhancing the gaming experience by reducing potential disruptions.

Key concepts

Nonpersistent CSMA

Nonpersistent CSMA is a network protocol where each device checks if the communication medium is free before sending data. If the medium is busy, the device waits for a random amount of time and checks again. This method aims to reduce the chances of a collision, but it doesn't eliminate them entirely.
When using nonpersistent CSMA:

• Devices operate independently, reducing the coordination needed between them.
• There is a risk of collisions, especially when several devices become ready to send data at the same time after the medium becomes free.
• Collisions result in the need for retransmissions, causing delays.

While nonpersistent CSMA can be efficient in networks with lighter traffic, in high-traffic environments like interactive gaming, the risk of collisions can lead to disruptive delays.

Token Ring Protocol

The token ring protocol provides a structured way of managing access to the network. In this system, a token circulates continuously among all devices connected to the network. A device can only send data when it possesses the token, significantly reducing the chance of collisions.
This method involves:

• Seamless circulation of a token, ensuring orderly and predictable network access.
• Virtual elimination of data collisions, which is beneficial for high-demand applications like gaming.
• A system where delays are controlled and can be predicted, enhancing the user experience for time-sensitive activities.

The predictability and reliability of the token ring protocol make it suitable for applications that require consistent network performance and low latency.

Wireless Network

A wireless network is a type of computer network that uses wireless data connections for connecting network nodes. Within a room where the signal can ripristate efficiently, such as the gaming setup described, wireless networks offer flexible and convenient connectivity without the need for physical cables.
A wireless network setup includes:

• Transmission of data via radio waves instead of through wired connections.
• Flexibility in device placement, as devices aren't restricted by cable lengths.
• Potential issues with interference or range limitations, though these are minimized in small, single-room environments.

In gaming, a reliable wireless network is crucial since it must support high data rates and low latency for seamless play. Proper network protocol selection within such a network is key to ensuring an optimal gaming experience.

Collision Avoidance

Collision avoidance is a critical aspect of maintaining network efficiency, particularly in environments where multiple devices are transmitting data simultaneously, like in a gaming session.
Effective collision avoidance involves:

• Utilizing protocols that prevent data collisions from occurring in the first place.
• Implementing mechanisms where devices are aware of network conditions and adjust their actions accordingly.
• Ensuring higher bandwidth usability and lower latency by reducing the need for data retransmissions.

Choosing a protocol that successfully avoids collisions, such as the token ring protocol, is essential in environments requiring consistent performance, like the gaming network described in the exercise.