Network redundancy (ring topology) in SCADA systems - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding ring topology redundancy

In a ring topology network used for SCADA systems, what is the primary advantage of having a ring structure for redundancy?

A It allows all devices to connect directly to a central hub for faster communication.

B If one connection breaks, data can still travel the opposite way around the ring to reach its destination.

C It reduces the number of cables needed by connecting devices in a straight line.

D It prevents any device from communicating unless all devices are active.

💡 Hint

Think about how data can flow if one link in the ring fails.

Ring topology allows data to flow in both directions. If one link breaks, the network can still send data the other way, maintaining communication.

💻 Command Output

intermediate

Interpreting ring topology failure detection output

You run a diagnostic command on a SCADA ring network device that outputs the following:

Link status: OK
Neighbor device: 192.168.1.2
Ring health: Broken at segment 3
Failover status: Active

What does this output indicate?

A The ring is fully operational with no breaks or failover.

B All ring segments are healthy and no failover is needed.

C The ring has a break at segment 3, but failover is active to maintain communication.

D The device cannot detect any neighbors and the ring is down.

💡 Hint

Look at the 'Ring health' and 'Failover status' lines carefully.

The output shows a break in the ring at segment 3, but failover is active, meaning the network is using the backup path to keep communication alive.

❓ Configuration

advanced

Configuring ring redundancy protocol on SCADA switches

Which configuration snippet correctly enables a ring redundancy protocol on a SCADA network switch to detect and recover from link failures?

A

ring-protocol enable
ring-timer 300
ring-port 1
ring-port 2

B

ring enable true
timer=300
ports=1,2

C

enable ring
set timer 300
ports add 1 2

D

activate ring
timer 300
port1 enable
port2 enable

💡 Hint

Look for the correct syntax to enable ring protocol and specify ports and timer.

Option A uses the correct commands to enable the ring protocol, set the timer, and specify the ring ports on the switch.

❓ Troubleshoot

advanced

Diagnosing ring topology failover failure

A SCADA ring network fails to switch to the backup path after a link break. Which of the following is the most likely cause?

A The devices are connected in a star topology, not a ring.

B The network cables are all fiber optic instead of copper.

C The IP addresses of devices are not in the same subnet.

D The ring timer is set too high, delaying failover detection.

💡 Hint

Consider what controls how quickly failover happens in ring networks.

If the ring timer is set too high, the devices take longer to detect a break and switch to the backup path, causing failover failure.

🔀 Workflow

expert

Steps to restore ring topology after a link failure

Arrange the correct order of steps to restore full ring topology operation after a link failure in a SCADA network.

A 1,2,3,4

B 2,1,3,4

C 1,3,2,4

D 3,1,2,4

💡 Hint

Think about logical troubleshooting and repair steps from detection to confirmation.

First identify the break, then fix it physically, check protocol status, and finally test communication to confirm full restoration.