A technician sets up a small office network using two unmanaged switches to connect 25 computers. After connecting both switches to the router, the network becomes extremely slow and many computers lose connectivity intermittently. The technician notices that the router's status lights on all ports are flashing rapidly. Which of the following is the MOST likely cause of this issue?

A faulty router causing packet loss

While a faulty router can cause slowness, it would not typically cause all router port lights to flash rapidly simultaneously. A broadcast storm affects all devices on the same broadcast domain.

DNS server misconfiguration

DNS issues would prevent name resolution but would not cause intermittent loss of connectivity or rapid flashing of router port lights. The physical network would still function normally.

Incorrect DHCP scope size

Incorrect DHCP scope could cause some computers to fail to obtain an IP address, but it would not cause network-wide saturation or rapid flashing of all router ports. Existing connections would remain stable.

What does this 220-1101 question test?

CIDR notation defines the prefix length.

What is the correct answer to this question?

The correct answer is: A broadcast storm caused by a network loop — When two unmanaged switches are connected to each other by two separate cables (or inadvertently connected in a loop), a network loop is created. Without Spanning Tree Protocol (STP), which is not present on unmanaged switches, broadcast frames circulate endlessly, causing a broadcast storm. This floods the network with traffic, overwhelming the router and switches, leading to high port activity, packet loss, and severe performance degradation. A faulty router, DNS misconfiguration, or incorrect DHCP scope would not cause such widespread, immediate symptoms with rapid flashing lights on all ports.

What should I do if I get this 220-1101 question wrong?

Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.