- How is a repeater different from an amplifier?
- What do we mean when we say that a bridge can filter traffic? Why is filtering important?
- What is a transparent bridge?
- How does a repeater extend the length of a LAN?
- How is a hub related to a repeater?
- What is the difference between a forwarding port and a blocking port?
The Correct Answer and Explanation is :
1. How is a repeater different from an amplifier?
A repeater and an amplifier both serve to extend the range of signals, but they function in different ways.
- A repeater is an electronic device that receives a signal, amplifies it, and then retransmits it without altering the signal itself. It works by cleaning up the signal, removing noise, and retransmitting it to extend its range. It is used to maintain signal integrity over long distances, such as in network communication.
- An amplifier, on the other hand, simply increases the strength of a signal without any filtering or correction of noise. It amplifies the existing signal, including any degradation or noise it may have accumulated over a distance. An amplifier is typically used in audio and radio applications.
2. What do we mean when we say that a bridge can filter traffic? Why is filtering important?
A bridge filters traffic by selectively passing or blocking data between two segments of a network based on the MAC addresses of the devices involved. Filtering ensures that only relevant data is forwarded, reducing congestion on the network. It acts like a gatekeeper, checking if the destination address of a data packet is in the same segment or a different one. If it is within the same segment, the bridge will not forward it, reducing unnecessary traffic.
Filtering is crucial because it optimizes network performance by minimizing the traffic in each network segment, thus preventing collisions and reducing the chances of network congestion. It enhances efficiency by ensuring that only necessary data is transmitted to each network segment.
3. What is a transparent bridge?
A transparent bridge is a type of network bridge that operates invisibly to the devices on either side of the bridge. It does not require any configuration or modification of the devices in the network, which means the bridge “transparently” forwards data between the segments without the devices being aware of its presence. It learns the network’s MAC addresses and makes forwarding decisions based on that information, acting as an intermediary for data transmission.
4. How does a repeater extend the length of a LAN?
A repeater extends the length of a Local Area Network (LAN) by boosting and retransmitting the electrical signals between network devices. Over longer cable runs, signals degrade, causing a drop in signal strength and possible data loss. A repeater regenerates the weakened signal, amplifies it, and sends it again, allowing the network to span longer distances than would otherwise be possible. This ensures the signal integrity is maintained over extended distances, improving network performance and reliability.
5. How is a hub related to a repeater?
A hub can be thought of as a multi-port repeater. While a repeater typically has two ports and is used to extend the signal between two devices, a hub operates like a repeater but for multiple devices. It receives a signal from one device, amplifies it, and broadcasts it to all other connected devices, regardless of the destination. The hub essentially acts as a signal extender for multiple devices, similar to a repeater but with more ports.
6. What is the difference between a forwarding port and a blocking port?
In the context of bridges and network switches, the concepts of forwarding port and blocking port are part of the Spanning Tree Protocol (STP), which is used to prevent network loops and ensure efficient data transmission across multiple paths.
- A forwarding port is a port on a bridge or switch that is actively participating in forwarding data between network segments. It allows data packets to pass through to their destination. When a port is in the forwarding state, it is open for traffic, and the switch or bridge will forward frames based on the MAC addresses of the devices on the network.
- A blocking port, on the other hand, is a port that is not allowed to forward any data. It is in a “blocked” state to prevent network loops or congestion. The blocking port does not pass data frames and effectively stops any traffic from reaching the segment it is connected to. The blocking port is typically used when STP identifies a potential loop or redundancy and decides that the port should not be actively used to avoid an undesirable network condition.
300-Word Explanation:
The difference between a forwarding port and a blocking port stems from the Spanning Tree Protocol (STP), which is essential for preventing loops in network topologies where multiple redundant paths exist. Without STP, the network would encounter broadcast storms and infinite loops that could severely degrade performance or bring down the network entirely.
A forwarding port is used when a switch or bridge determines that it is safe to send data through that port. The decision is based on the topology of the network, and if that port leads to a network segment where data can safely be forwarded to its destination, it will be marked as “forwarding.” This port is open and actively transmits traffic.
In contrast, a blocking port is used when the switch or bridge detects that using a particular port could create a loop or redundant path that would interfere with the network’s performance. The port is blocked to ensure that data is not forwarded through a route that could cause a network-wide disruption. It is part of STP’s loop prevention mechanism.
The dynamic allocation of forwarding and blocking ports helps ensure that the network operates efficiently, using optimal paths for data flow while preventing issues caused by network loops. The blocking port state is temporary, and if the topology changes, it may switch to a forwarding state if necessary to balance network traffic and redundancy. This process allows networks to maintain high availability and prevent downtime due to routing errors.