Be able to configure VLANs, trunks, and SVIs, and verify them with show vlan, show interfaces trunk, and show ip interface brief. The single most important thing: confirm the VLAN exists, is allowed on the trunk, and has an active SVI before troubleshooting routing.
Start practicing
Infrastructure — choose a session length
Free · No account required
Domain overview
Infrastructure covers how Cisco switches and routers move frames and packets: VLANs, trunking, inter-VLAN routing, STP, EtherChannel, and the Cisco hierarchical design model. Questions are scenario-based, asking you to pick the right protocol, command, or design layer to isolate traffic, restore connectivity, or enable remote management.
Exam objectives
VLAN creation, access and trunk port assignment, and 802.1Q encapsulation on Cisco switches
Inter-VLAN routing using SVIs on Layer 3 switches or router-on-a-stick subinterfaces
VTP for dynamic VLAN propagation, plus STP and EtherChannel for loop-free redundant links
Management access via dedicated management VLAN, SSH, and switch virtual interfaces
Confusing VTP modes: only server mode can create, modify, or delete VLANs and propagate them; client and transparent cannot originate changes.
Forgetting that a trunk port must allow the VLAN and that the SVI needs an IP address and no shutdown before inter-VLAN routing works.
Assuming management traffic is isolated by default; it requires a dedicated management VLAN and correct access restrictions.
Click any question to see the full explanation and answer options, or start a focused practice session above.
A network administrator needs to connect a workstation to a Cisco switch. Which cabling standard and medium should be utilized to ensure full-duplex communication while preventing collision domains?
2Which device is primarily responsible for managing traffic between different IP subnets in a corporate network?
3Which TWO functions are performed by a Cisco switch at the Data Link layer? (Choose two.)
4Which THREE factors influence the selection of a specific router interface for traffic forwarding? (Choose three.)
5An administrator wants to implement a security policy that prevents unauthorized devices from accessing the network via open switch ports. Which feature should be enabled to achieve this?
6Which primary benefit does the implementation of VLANs provide to a corporate network infrastructure?
7Which transmission medium is best suited for long-distance data communication with high immunity to electromagnetic interference?
8What is the function of the Default Gateway in an IP configuration?
9Which TWO protocols are commonly used to remotely manage Cisco network devices? (Choose two.)
10What is the primary function of a network switch's 'store-and-forward' switching method?
11Which mechanism does the Spanning Tree Protocol (STP) use to detect and prevent Layer 2 loops in a network with redundant links?
12An enterprise network administrator needs to deploy a secure out-of-band management network for enterprise switches and routers. Which infrastructure design approach provides the highest level of isolation and security?
13A network engineer is troubleshooting high CPU utilization on a core switch caused by excessive broadcast traffic across multiple VLANs. Which infrastructure technology should be deployed to contain broadcast domains while maintaining Layer 3 connectivity?
14An organization is designing a redundant campus distribution layer to ensure high availability and fast failover. Which TWO infrastructure features should be implemented to achieve sub-second convergence and eliminate routing loops? (Choose two)
15Which cabling infrastructure standard should an engineer deploy to support 10 Gigabit Ethernet transmissions across a 300-meter horizontal run inside a modern enterprise building?
16Refer to the exhibit. An engineer observes that the interface status for Vlan100 is listed as 'up' but the protocol status is 'down'. What is the most likely root cause of this operational state?
17An administrator is configuring Power over Ethernet on an enterprise access switch to power IP security cameras requiring up to 25.5 watts of power each. Which IEEE standard must the switch ports support?
18An enterprise network design incorporates Power over Ethernet to supply power to VoIP desk phones and wireless access points. A technician notes that the power supply unit inside the switch is operating near maximum capacity. Which feature should be configured to prevent unexpected power drops?
19A network administrator needs to connect two switches using a link that allows multiple VLANs to traverse a single physical path. Which configuration step is essential to ensure this functionality is enabled properly?
20Refer to the exhibit. An administrator observes high error counts on a switch port. Based on the output, what is the most likely cause of the issue?
21Which TWO of the following are primary benefits of implementing a hierarchical network design like the Cisco Three-Tier Model?
22Which device is primarily responsible for performing inter-VLAN routing in a modern enterprise network?
23What is the primary purpose of a default gateway in an IP host configuration?
24Which type of cabling is best suited for long-distance data transmission that requires high bandwidth and is immune to electromagnetic interference?
25Refer to the exhibit. If a third device with a different MAC address is connected to this port, what will occur?
26Which protocol is used to provide dynamic, automatic configuration of VLANs across a domain of switches?
27Which THREE of the following are characteristics of the Cisco IOS CLI environment that facilitate efficient network administration?
28A switch is experiencing high levels of broadcast traffic. Which technology can be used to divide the switch into smaller, independent broadcast domains?
29What is the primary function of the 'show running-config' command on a Cisco switch?
30Which component of the Cisco network architecture is specifically designed to provide high-speed switching and fast transport between different parts of the network?
31What is the primary function of the Spanning Tree Protocol (STP) in a network with redundant links?
32Refer to the exhibit. What can be determined about the status of interface FastEthernet 0/1?
33A technician connects a new laptop to a Cisco Catalyst switch. The switch receives a frame destined for a MAC address that is not currently present in its MAC address table. What action will the switch take to ensure the frame reaches its intended destination?
34A network technician is configuring a new Cisco switch port for a server that must support both voice and data traffic on separate VLANs. The server's network interface card is VLAN-aware and will tag its own frames. The technician wants to ensure the switch port can carry traffic for multiple VLANs. Which type of switch port configuration should the technician apply?
35A network technician is configuring a new Cisco switch and needs to assign an IP address to the management VLAN interface so the switch can be reached remotely via SSH. The switch currently has no VLAN interfaces configured. Which command must the technician use to create the management interface and enter interface configuration mode?
36A network administrator is setting up a small office network with a Cisco router and several switches. The administrator wants to ensure that devices on the local network can communicate with each other and access the internet. Which IP address configuration parameter must be set on each device to allow communication with remote networks?
37A network technician connects a new Cisco Catalyst switch to an existing production switch using a copper straight-through cable. The link lights on both ends remain off, and the technician confirms the cable is functional. The technician then replaces the cable with a crossover cable, and the link comes up. What is the most likely reason the straight-through cable failed to establish a link?
38A user reports that they cannot access any network resources, including the internet. A technician checks the user's workstation and finds that it has an IP address of 169.254.10.5 with a subnet mask of 255.255.0.0. The technician verifies that the switch port is active and the cable is connected. What is the most likely cause of the problem?
39A network administrator is setting up a small office network with a single Cisco router and multiple switches. The administrator wants to ensure that devices on different VLANs can communicate with each other. Which feature should be configured on the router?
40A network engineer is deploying a new Cisco switch and needs to configure it for remote management. The engineer wants to ensure that management traffic is isolated from user data traffic and that only authorized personnel can access the switch. Which two configuration steps should the engineer perform? (Choose two.)
41A network administrator is configuring a Cisco switch and wants to ensure that only the MAC addresses of known devices are allowed to send traffic on a specific access port. The administrator wants to manually specify the allowed MAC addresses and have the port shut down if a violation occurs. Which feature should be configured?
42A network engineer is configuring a Cisco switch and needs to ensure that only the MAC address 00:1A:2B:3C:4D:5E is allowed to communicate through interface GigabitEthernet0/1. The engineer enters the command 'switchport port-security mac-address 00:1A:2B:3C:4D:5E' on the interface. However, the switch rejects the command. What is the most likely cause?
43A small branch office has a Cisco Layer 2 access switch with three access ports assigned to VLAN 10 for the sales team and two access ports assigned to VLAN 20 for the finance team. The finance team reports that they cannot reach the sales team's shared file server, even though both teams are connected to the same physical switch. No router or Layer 3 switch is deployed at this branch. What is the most likely explanation for the connectivity failure?
44A network administrator is troubleshooting a connectivity issue between two hosts on the same VLAN. The administrator uses the 'show mac address-table' command on the switch and notices that the MAC address of one host appears on multiple ports. What is the most likely cause of this behavior?
45A network administrator is troubleshooting a connectivity issue between two switches connected via a trunk link. The administrator notices that the trunk link is up, but VLAN 10 traffic is not passing. The administrator runs the show interfaces trunk command and sees that VLAN 10 is not listed in the 'VLANs allowed and active in management domain' output. What is the most likely cause?
46A technician is deploying a new Cisco switch in a wiring closet and needs to connect it to a distribution switch so that it can carry traffic for VLAN 5, VLAN 15, and VLAN 25 between the two devices. The link must carry frames from all three VLANs simultaneously. Which type of port configuration should be applied to the uplink interface on both switches?
47A network technician is configuring a new Cisco switch for a small business. The technician needs to ensure that the switch can be managed remotely from a different subnet. Which TWO configurations are required to enable remote management access? (Choose two.)
48A network technician is configuring a Cisco switch for a new VLAN. The technician wants to verify that the VLAN has been created and is active, and also see which ports are assigned to it. Which command should the technician use?
49A network engineer is reviewing how a Cisco switch builds and maintains its MAC address table as frames arrive from attached devices. Which TWO statements correctly describe this Layer 2 forwarding behavior? (Choose two.)
50A network administrator is reviewing the MAC address table on a Cisco access switch and notices that the same MAC address appears on two different access ports in the same VLAN. The administrator confirms that the device with that MAC address is connected to only one port. What is the most likely cause of this duplicate entry?
51A network engineer is configuring a Cisco router interface that connects to an ISP. The ISP has assigned the engineer a single public IP address of 203.0.113.10 with a subnet mask of 255.255.255.252 and a default gateway of 203.0.113.9. The engineer needs to configure the router interface with the correct IP address and mask. Which configuration should be applied?
52A network administrator is deploying a new Cisco switch in a small office and wants to apply basic security hardening to protect the management plane. The administrator plans to restrict remote access and prevent unauthorized configuration changes. Which two actions should the administrator take to secure management access to the switch? (Choose two.)
53Users on VLAN 20 report that they can reach servers on VLAN 30 but cannot reach any hosts on VLAN 40. The administrator confirms that inter-VLAN routing is configured on a Layer 3 switch with switched virtual interfaces for all three VLANs. Which action should the administrator take first to isolate the problem?
Be able to configure VLANs, trunks, and SVIs, and verify them with show vlan, show interfaces trunk, and show ip interface brief. The single most important thing: confirm the VLAN exists, is allowed on the trunk, and has an active SVI before troubleshooting routing.
The Courseiva 100-150 question bank contains 53 questions in the Infrastructure domain. Click any question to see the full explanation and answer breakdown.
Start with a 10-question focused session to identify your baseline accuracy in this domain. Read every explanation — even for questions you answer correctly — to understand the reasoning. Once you score consistently above 80%, move to a 20–30 question session to confirm depth before moving to the next domain.
Yes — the session launcher on this page draws questions exclusively from the Infrastructure domain. Choose 10, 20, 30, or 50 questions for a focused session, or click individual questions to review them one by one.
Save your results, see per-domain analytics, and get readiness scores — free, for every certification.
Sign Up FreeFree forever · Every certification included