Aruba Certified Switching Associate (ACSA) Interview Questions

Employers are always on the search for well-rounded individuals that can assist the firm or business in achieving its goals, which explains why recruitment processes are becoming more thorough over time. To get a job, you must provide something extra. We’ll look at some of the questions you’ll be asked during a switching interview in this article. These should provide a solid foundation for you to succeed in the Aruba Certified Switching Associate (ACSA) interview. We’ve also created our own responses to help you figure out how to respond to the questions. Let’s take a closer look at these:

What is VLAN and how does it work in Aruba switches?

A VLAN (Virtual LAN) is a network segmentation method used to divide a physical network into multiple logical subnets. In Aruba switches, VLANs are used to segment network traffic and improve network security and organization.

Each VLAN operates as a separate network, with its own broadcast domain, allowing devices within the same VLAN to communicate directly without the need for routing. Traffic between different VLANs must pass through a router to be transmitted.

In Aruba switches, VLANs are configured by assigning switch ports to specific VLANs and tagging traffic on those ports with the appropriate VLAN ID. The switch then forwards the tagged traffic to the appropriate VLAN and ensures that traffic from different VLANs remains separate.

How does Spanning Tree Protocol (STP) work and what is its purpose in Aruba switches?

Spanning Tree Protocol (STP) is a network protocol used to prevent loops in a network topology by selecting a single active path for network traffic to flow. The purpose of STP in Aruba switches is to prevent bridging loops and ensure that network traffic flows correctly.

STP operates by selecting one switch in the network as the root bridge and determining the best path to the root bridge. The root bridge then sends out a “topology change notification” to the other switches in the network, which then recalculate their forwarding tables to reflect the new network topology.

In Aruba switches, STP is enabled by default and operates automatically, but it can be configured and optimized for specific network requirements. For example, the root bridge can be manually specified, and certain switch ports can be designated as “edge ports” to improve network performance.

Can you explain the role of the Spanning Tree Protocol (STP) in a network?

Spanning Tree Protocol (STP) is a network protocol used to prevent the creation of loops in a network topology. Its role is to ensure that there is only one active path for network traffic to flow between any two points in a network.

STP operates by selecting a root switch, which is the center of the network, and determining the best path to the root switch for each switch in the network. The root switch then sends out a “topology change notification” to the other switches in the network, which then recalculate their forwarding tables to reflect the new network topology.

If a loop occurs in the network, STP will detect it and block one of the redundant links to prevent the loop. This allows the network to continue to operate normally, without the negative effects of looping traffic.

In summary, the role of STP is to maintain a stable network topology by preventing the formation of loops and ensuring that there is only one active path for network traffic to flow.

How would you configure VLANs and VLAN tagging on an Aruba switch?

Here is a high-level overview of how to configure VLANs and VLAN tagging on an Aruba switch:

1. Connect to the Aruba switch using a terminal client and log in with administrative credentials.
2. Enter configuration mode by typing “configure” at the command prompt.
3. Create a new VLAN by typing “vlan <VLAN ID>” and replacing “<VLAN ID>” with the desired VLAN ID number.
4. Assign a name to the VLAN by typing “name <VLAN name>” and replacing “<VLAN name>” with the desired VLAN name.
5. Assign switch ports to the VLAN by typing “untagged <port list>” and replacing “<port list>” with the list of switch ports to be assigned to the VLAN (e.g. “1-24”).
6. Enable VLAN tagging on the switch ports by typing “tagged <port list>” and replacing “<port list>” with the list of switch ports that should send and receive tagged VLAN traffic (e.g. “25-48”).
7. Save the configuration by typing “write memory”.

This is a basic configuration, and additional steps may be required depending on the specific requirements of your network. It is also recommended to review the Aruba switch user guide and best practices for configuring VLANs and VLAN tagging.

Have you worked with Aruba’s Mobility Master and how does it manage wireless access points?

Aruba’s Mobility Master is a central management solution for Aruba’s wireless access points. It provides centralized control, configuration, and monitoring for wireless access points, allowing network administrators to manage their wireless network from a single interface.

The Mobility Master acts as the single source of truth for the wireless network, maintaining a consistent configuration and policy across all access points. It communicates with access points over the network to distribute configuration changes, monitor network performance, and provide real-time statistics on network usage and traffic.

Additionally, the Mobility Master provides advanced network management features such as real-time network monitoring, client tracking, and rogue access point detection. It also supports advanced wireless security features, including wireless intrusion detection and prevention, to help ensure the security of the wireless network.

In summary, the Mobility Master acts as the central management point for Aruba’s wireless access points, providing a single interface for configuring, monitoring, and managing the wireless network.

Can you explain how to set up Quality of Service (QoS) on an Aruba switch?

Here is a high-level overview of how to set up Quality of Service (QoS) on an Aruba switch:

1. Connect to the Aruba switch using a terminal client and log in with administrative credentials.
2. Enter configuration mode by typing “configure” at the command prompt.
3. Define the classes of service (CoS) by typing “qos class <class name> <priority>” and replacing “<class name>” with the name of the class of service and “<priority>” with the desired priority level.
4. Define the rules for mapping traffic to the classes of service by typing “qos rule <rule name> match <criteria> action <class name>”. Replace “<rule name>” with the name of the rule, “<criteria>” with the traffic match criteria (e.g. source IP address), and “<class name>” with the name of the class of service to which the traffic should be mapped.
5. Enable QoS on switch ports by typing “qos apply <port list>” and replacing “<port list>” with the list of switch ports that should have QoS enabled (e.g. “1-24”).
6. Save the configuration by typing “write memory”.

This is a basic configuration, and additional steps may be required depending on the specific requirements of your network. It is also recommended to review the Aruba switch user guide and best practices for configuring Quality of Service (QoS).

Have you used Aruba’s ClearPass policy manager? If so, can you give an example of how you have used it in a network deployment?

Aruba’s ClearPass Policy Manager is a network access control solution that provides authentication, authorization, and accounting (AAA) services for wireless, wired, and VPN networks. It integrates with various network access technologies, including 802.1X, MAC authentication, and captive portal, to provide a flexible and comprehensive network access control solution.

An example of how ClearPass Policy Manager can be used in a network deployment is to enforce role-based network access. In this scenario, the ClearPass Policy Manager can be configured to allow different types of users (e.g. guests, employees, contractors) to access different parts of the network based on their role. For example, guests may be limited to Internet access only, while employees may have full network access.

To implement this, the network administrator would first define the different roles in ClearPass Policy Manager and assign network access privileges to each role. Then, the administrator would configure the network access devices (e.g. wireless access points, switches) to send authentication requests to ClearPass Policy Manager. Finally, the administrator would configure ClearPass Policy Manager to enforce the defined network access policies based on the user’s role.

In this way, ClearPass Policy Manager can be used to enforce role-based network access and ensure that only authorized users have access to the network resources they need. This helps to improve network security and reduce the risk of unauthorized access.

Can you discuss the differences between static and dynamic IP addressing and when to use each in a network?

Static and dynamic IP addressing are two methods of assigning IP addresses to devices in a network.

Static IP addressing involves manually assigning a unique IP address to each device in a network. This IP address remains fixed and does not change over time, unless it is manually modified by an administrator. Static IP addresses are useful when you need to remotely access a device, or when you need to configure a device as a server, such as a web server or a file server.

Dynamic IP addressing involves assigning IP addresses to devices from a pool of available addresses, using a protocol such as DHCP (Dynamic Host Configuration Protocol). In this case, the IP address assigned to a device may change over time, such as when the device is restarted or when its lease with the DHCP server expires. Dynamic IP addressing is useful for networks where a large number of devices are connected, as it reduces the administrative overhead of manual IP address assignments.

In general, static IP addressing is best for servers, printers, and other devices that need to be accessed remotely, while dynamic IP addressing is best for client devices that do not require a permanent IP address. However, the specific needs of your network will dictate which type of IP addressing is most appropriate for your network environment.

Have you worked with Aruba’s Network Analytics and Performance Optimization (NAPO) solution?

Aruba’s NAPO solution is a network analytics and performance optimization tool that provides network visibility and performance optimization through real-time network analysis and data collection. It provides network administrators with a comprehensive view of network performance and helps to identify and resolve performance issues in real-time.

NAPO collects data from various sources within the network, such as switches, routers, and wireless access points, and uses machine learning algorithms to analyze the data and identify performance issues. The tool provides a range of features, including real-time performance monitoring, network topology visualization, and automatic root cause analysis, to help network administrators quickly identify and resolve performance issues.

In summary, Aruba’s NAPO solution provides network administrators with a powerful tool for monitoring and optimizing network performance, helping to ensure that network resources are used effectively and that network performance is optimized.

Can you discuss your experience with troubleshooting network issues and provide an example of a complex issue you have resolved?

Troubleshooting network issues involves identifying the root cause of a problem and implementing a solution to resolve the issue. This can be a complex process, especially when dealing with issues that impact multiple components of the network.

A common example of a complex network issue is slow network performance. Slow network performance can be caused by a variety of factors, including network congestion, high network utilization, network configuration issues, and hardware problems.

To resolve a slow network performance issue, network administrators would typically start by gathering information about the network environment and the devices involved. This information can be gathered through a variety of tools, such as network analyzers and performance monitoring tools.

Once the information has been gathered, the administrator would analyze the data to identify the root cause of the problem. For example, if the issue is network congestion, the administrator might look for bottlenecks in the network, such as high utilization on specific network segments or devices.

Once the root cause of the issue has been identified, the administrator can then implement a solution to resolve the problem. For example, if the issue is network congestion, the administrator might implement traffic management strategies to reduce network utilization and prevent further congestion.

In summary, resolving complex network issues involves a structured approach to identifying the root cause of the problem and implementing a solution to resolve the issue. Network administrators need to be knowledgeable about network technologies, have a strong understanding of the network environment, and be familiar with the tools and techniques used to troubleshoot network issues.

1.What exactly is Switching?

Switching is used to move data packets across devices on the same network.

2. What is the definition of “switch”?

A switch is a device that connects numerous devices together in a Local Area Network (LAN). Instead of simply repeating the signal to all ports, switches evaluate each packet and process it accordingly, unlike hubs. Switches are part of the OSI model’s Layer Two (Data Link Layer).

3. What is the distinction between a hub, switch, and router?

Hub is designed to link hosts without knowing what they’re sending or receiving. When a Hub gets a data packet from a connected device, it broadcasts it to all other ports, independent of the destination port. HUB is a Layer 1 network.

Switch also acts as a hub, connecting hosts to one another. The way a switch processes packets differs from that of a hub. When a switch gets a packet, it decides which hosts it is meant for and sends it solely to those addresses. It doesn’t broadcast the packet to all hosts like a hub, therefore bandwidth isn’t shared and the network is more efficient.

4. What are the purposes of switches?

The Switch has three primary functions:-

• Address the issue of education.
• Filtering and forwarding of packets.
• Spanning Tree Protocol avoids loops.

5. What exactly is a sub interface?

The router’s interface is separated into logical interfaces—one for each VLAN—to support ISL or 802.1Q routing on a Fast Ethernet interface. These are referred to as subinterfaces.

6. Define Broadcast domain.

Broadcast Domain – Broadcast is a method of communication in which a single copy of data is sent from one device to all other devices in the network segment. Every broadcast packet originating from any device within the network segment will be received by a Broadcast Domain, which is made up of all the devices that will receive it. By default, all ports on a hub or switch are in the same broadcast domain. A router’s ports are all in different broadcast domains, and routers do not forward broadcast traffic.

7. Explain Collision domain.

Collision Domain – is a network scenario in which one device delivers a packet over a network segment, causing all other devices on that segment to pay attention to it. If another device tries to transmit at the same moment, it will cause a collision, and both devices will have to retransmit one at a time. Because each port on a hub is in the same collision domain, this circumstance occurs frequently. Each port on a bridge, switch, or router, on the other hand, is in its own collision domain.

8. What is the difference between a hub and a switch in terms of broadcast and collision domain?

• One collision domain and one broadcast domain exist in Hub.
• There are many collision domains and one broadcast domain in Switch.

9. What is a mac address table, and how does a switch create one?

The switch uses an address table called the MAC address Table or CAM Table to efficiently exchange frames between LAN ports (Content Addressable Memory Table). When the switch receives a frame, the source MAC address, as well as the port of arrival, VLAN, and time stamp, are learned and entered in the CAM table. The MAC address table is dynamically built by the switch using the Source MAC address of the frames received. The switch then uses this table to identify where traffic on a LAN should be sent.

10. How does switch acquire mac addresses?

When an Ethernet frame arrives at a switch’s port, the switch reads the source device’s MAC address from the frame and compares it to its MAC address table (also known as the CAM (Content Addressable Memory) table). If the switch cannot find a comparable entry in the MAC address table, it will add the address to the table along with the Ethernet frame’s port number. If the MAC address is already in the MAC address table, the switch compares the incoming port to the one that is already in the MAC address table. The switch updates the MAC address table with the new port number if the port numbers are different.

11. What is the process by which a switch performs the forwarding function?

When a Layer 2 Ethernet frame arrives at a Switch port, it is read not only the source MAC address as part of the learning function, but also the destination MAC address as part of the forwarding function. The destination MAC address is needed to figure out which port the destination device is connected to. When the switch finds the target MAC address in the MAC address table, it forwards the Ethernet frame to the MAC address’s matching port.

12. What is flooding and how does it happen?

The switch forwards the frame out all of its ports except the one on which it was received if the target MAC address is not found in the MAC address table. This is referred to as flooding.

13. What is your definition of VLAN and what are some of the most common types?

It is a custom network formed from one or more local area networks and is formally known as the Virtual Local Area Network. It builds a Virtual LAN by combining devices from many networks into a single logical network. VLANs are divided into three categories: port-based, protocol-based, and MAC-based. The first, as the name implies, employs a port to group virtual area networks. Protocol VLAN, on the other hand, employs traffic that follows a protocol, whereas MAC-based VLAN permits untagged packets to be assigned to a Virtual LAN.

14. Could you please elaborate about Unicast Traffic?

This is frequently linked to the network switch’s learning process. The switches use their ports to locate the MAC addresses of the accessible devices before creating a table to determine the destination of each arriving frame. It may, however, result in unicast flooding, with periods ranging from bad performance to no network.

15. What Is Spanning Tree Protocol and How does it work? Could you further elaborate on your background in this field?

The Spanning Tree Protocol, or STP for short, eliminates the undesired network loops that occur when many levels of redundancy are attempted. It’s a link management protocol that provides path redundancy, which solves this issue. In the wake of several links, it permits just one path to destinations. As a result, the switches permit data interchange using bridge protocol data units.

16. Could you tell us about some of the functions of switches now that you’ve worked with them?

A switch has four primary purposes. The first is determining a device’s MAC or physical address on a switch port. The second is framing, which creates a known and unknown unicast. Filtering, in which the frame is passed through a switch port where the switch has learned the MAC address, and loop avoidance through spanning tree protocols are the third and fourth options. (You don’t have to go into great depth.) However, you are free to elaborate.)

17. Please distinguish between Broadcast and Collision Domain in Aruba Certified Switching Associate (ACSA).

• A collision domain allows traffic to flow in a network area where traffic is exchanged, whereas a broadcast domain allows traffic to flow throughout the network.
• In the collision domain, switches generally break, but this does not happen in the broadcast domain.
• In a collision domain, each port on the router is discovered in its own broadcast domain, whereas in the broadcast domain, all the ports on the switch or hub are found in the same area.
• Devices from other IP subnetworks can be included in a collision domain, which is a limitation that broadcast domains do not have.

18. What do you understand by vlan tagging in Aruba Certified Switching Associate (ACSA)?

This technology, also known as frame tagging, was devised to assist systems in identifying all packets travelling across a trunk link. When this happens, a special VPN tag is formed and added to the frame before it is transferred across the link. When the frame reaches the end of the trunk line, the tag is removed and the frame is transmitted to the right access link port.

19. Could you please use your years of switching experience to explain the concept of cut-through LAN switching?

The router sends out a data frame as soon as it gets it in this type of switching. Once the frame’s destination address has been read, something is done to advance it to the next network segment. It’s one of the most exciting switching methods.

20. What are data pockets made up of?

There are four contents in a data packet. It contains information on the sender and recipient, as well as data and an identification number. An identification number is a number that specifies the packet number as well as the order. Data is split down into data packets, which carry bits of information, whenever it is delivered across a network. As a result, the data packets contain both information and routing configuration for the transferred message.

21. Please explain the differences between Unicast, Multicast, Broadcast, and Anycast.

Unicast refers to communication between a single source and a single destination. The data address of the recipient is included in the packets delivered, so they are forwarded straight to the receiver. The exchange of information or messages between one sender and all possible receivers is known as broadcasting.

Multicast, on the other hand, entails the transmission of messages between a sender and several receivers. Unlike broadcast, however, the receiving clients are determined by the network parameters. Finally, anycast is a method of sending messages from one host to another. TCP and UDP protocols are used, and a copy of each data packet is sent to the correct host.

22. What are data pockets made up of?

There are four contents in a data packet. It contains information on the sender and recipient, as well as data and an identification number. An identification number is a number that specifies the packet number as well as the order.

Data is split down into data packets, which carry bits of information, whenever it is delivered across a network. As a result, the data packets contain both information and routing configuration for the transferred message.

23. What does an ip address mean to you? Could you please explain what you’re talking about?

The Internet protocol address (IP address) is a 32 to 128-bit identifier assigned to any TCP/IP device. It’s usually a one-of-a-kind number or figure that’s used to identify the connected item and is explicitly defined for communication. The host and location addresses are the two main purposes of an IP address. There are two versions of IP: IPv4, which is 32 bits, and IPv6, which is 128 bits.

24. How well do you understand network congestion in Aruba Certified Switching Associate (ACSA)?

When a network node carries more data than the network can process, network congestion occurs. In such cases, the network node loses packets and information, preventing the recipient from receiving the necessary information.

25. Please describe the OSI Model’s many layers in Aruba Certified Switching Associate (ACSA).

The OSI model is divided into seven layers, each with its own set of functions. The physical layer is the first, followed by the data link layer and finally the network layer. The transport layer, session layer, presentation layer, and application layer were the other four layers. Remember that in the OSI model, each of these layers has its own set of functions.

26. Mention the IPX Access Lists’ Two Main Lists in Aruba Certified Switching Associate (ACSA).

Standard and extended IPX access lists are the two types of IPX access lists that are currently available. The IP address of the source or destination is the sole thing that the conventional access lists filter. The extended access lists, on the other hand, use the source and destination IP addresses, as well as the protocol and socket, to filter a network.

27. What do you mean when you say “Subnetting”?

It is the division of a parent network into smaller networks. Additional parameters are frequently assigned to all subnets, indicating their subnet numbers.

28. Please explain the function of the Application Layer in terms of networking now that you’ve listed the different layers of the OSI Model.

An application’s communication components are supported by the application layer. It also provides network services to application processes that aren’t covered by the OSI reference model specifications.

29. Explain how switches work in a few words. Has this changed over time as a result of your observations?

Throughout, the functioning mechanism of switches has remained consistent. Signals are received by these devices, which are then used to construct frames. When data is transmitted to the Data Link or Network layer of the OSI model, data packets are passed between various LAN segments because the switch offers packet control. It’s worth mentioning that when transmitting packets, the signals are enabled, so they can be accessed when the switch reads the destination address.

30. What are data pockets made up of in Aruba Certified Switching Associate (ACSA)?

There are four contents in a data packet. It contains information on the sender and recipient, as well as data and an identification number. An identification number is a number that specifies the packet number as well as the order.

Data is split down into data packets, which carry bits of information, whenever it is delivered across a network. As a result, the data packets carry both the message’s information and its routing configuration.