Question

Why would the token-ring protocol be inefficient if a LAN had a very large perimeter?

Short answer

A large perimeter leads to longer token circulation times, causing delays and inefficiencies.

Step-by-step solution

Understanding Token-Ring Protocol

The token-ring protocol is a type of network design in which a token, a small data packet, circulates around a network. A device must have possession of the token to send data over the network. This method ensures that there is no collision, as only one device can send data at any one time.

Role of Network Perimeter

The perimeter of a LAN refers to the physical or logical boundaries within which all network devices must communicate. A larger perimeter increases the distance data must travel around the ring to reach the intended recipient. This is important because it affects how long it takes for the token to complete one full circuit of the network.

Impact of Large Perimeter on Efficiency

With a larger perimeter, the token takes longer to travel around the entire network. This increased travel time results in longer wait times for devices wanting to send data, as each must wait for the token to reach them. These delays significantly reduce the protocol's efficiency.

Analysis of Data Transmission Delays

Since devices send data only when they have the token, any increase in time taken for the token to return increases the time data packets spend in queue. This can lead to idle times where no data is being transmitted, while all devices wait for their turn to get the token. Such delays magnify when added over multiple devices and transmissions.

Conclusion on Inefficiency

In summary, a large perimeter results in longer token circulation time around the ring, causing increased wait times for devices. This makes the protocol inefficient because it introduces unnecessary delays in data transmission, limiting the overall throughput of the network.

Key concepts

Network Perimeter

When discussing the network perimeter in the context of a token-ring protocol, we refer to the overall boundary of a Local Area Network (LAN). This boundary encompasses all the devices interconnected to form a complete loop. In a token-ring network, a small data packet, called a token, travels around this loop, allowing devices to communicate in an orderly manner.
The larger the network perimeter, the more time it takes for the token to travel around the entire loop. This physical or logical distance impacts how quickly data can be transmitted across the network.
It's important to note:

• The token needs to circulate the entire network to allow each device an opportunity to send data.
• A larger perimeter means the token spends more time traveling, which can introduce delays.

Understanding the network perimeter's role is essential, as it directly impacts the token's journey time around the ring.

Data Transmission Delays

Data transmission delays are a key aspect to consider when analyzing the efficiency of a token-ring protocol. In this type of network, a device can only send data once it obtains the token. The time it takes for the token to circulate back to any given device is critical, as longer times mean longer waits for devices wanting to sends their data.
Here's what happens:

• A larger network perimeter increases the token circulation time.
• This increase leads to longer waiting periods for all devices in the network.
• Idle times grow as the devices wait for the token, not just affecting one device, but extending across the entire network.
• Cumulative delays arise, as each device waits for the token to complete its loop, slowing down overall data transmission.

By understanding these delays, we can identify how they hinder the smooth function of a large token-ring network.

Network Efficiency

Network efficiency, within the context of a token-ring protocol, is the ability of a network to handle data transmissions swiftly and with minimal delays. An efficient network is one that minimizes downtime and ensures a continuous data flow.
However, as the network perimeter increases, efficiency tends to decline:

• In longer networks, the token takes more time to complete its circuit.
• This creates unnecessary delays, as devices must wait for the token to arrive before initiating data transmission.
• Delays result in longer cycle times for data to pass through the network, thus reducing overall throughput.
• In extreme cases, this inefficiency can make a network unsuitable for time-sensitive communications, where quick data transmission is critical.

By addressing these inefficiencies, one can look to optimize the network setup, potentially adopting different protocols or configurations to suit larger network environments better.