300-615 Cisco Practice Test Questions and Exam Dumps
Question 1 :-
A server fails to boot from the operating system after migrating a RAID1 cluster. The RAID remains in an inactive state during and after the service profile association. Which action should be taken to resolve this issue?
A. Configure the SAN boot target in the service profile.
B. Configure the SAN boot target to any configuration mode.
C. Use a predefined local disk configuration policy.
D. Remove the local disk configuration policy.
Answer:
A. Configure the SAN boot target in the service profile.
Explanation:
When performing a RAID1 migration or server migration, it is essential to ensure that the server can properly boot from its storage array, especially in environments that use Storage Area Networks (SANs). In this specific scenario, after the migration of the RAID1 cluster, the server fails to boot from the operating system, and the RAID remains inactive during and after the service profile association. This suggests that there is an issue with the configuration of the boot process, particularly the mapping of the boot target.
The key to resolving this issue lies in configuring the SAN boot target correctly. The SAN boot target is a critical parameter that tells the server which storage location to use when initiating the boot process. This configuration must be set in the server's service profile—a logical representation of the server's configuration, including CPU, memory, storage, and network settings.
Why Option A is Correct:
Option A, “Configure the SAN boot target in the service profile,” is the correct action because it ensures that the server knows which storage device to use for booting. If the SAN boot target is not configured properly or if it is missing, the server cannot locate the operating system on the RAID1 array, leading to boot failures.
When the server profile is associated with the hardware, it often involves linking the server to a specific SAN storage device that contains the OS. If the boot target is not set or misconfigured, the RAID array can remain inactive, and the boot process will fail. By configuring the SAN boot target in the service profile, the server will know where to find the operating system and complete the boot sequence.
Why the Other Options Are Incorrect:
Option B ("Configure the SAN boot target to any configuration mode") is incorrect because setting the boot target to any configuration mode will not resolve the specific issue of the inactive RAID. The correct target must be configured to point to the specific SAN device containing the bootable operating system.
Option C ("Use a predefined local disk configuration policy") is incorrect because the problem in this scenario involves the RAID array connected to the SAN, not a local disk. A local disk configuration policy is irrelevant in the context of SAN boot issues.
Option D ("Remove the local disk configuration policy") is incorrect because removing the local disk configuration policy will not affect the SAN boot configuration. The issue is with the RAID array and the SAN boot target, not a local disk configuration.
Conclusion:
In conclusion, the key to resolving the boot failure after RAID1 migration lies in ensuring that the SAN boot target is properly configured in the service profile. This action will allow the server to recognize the correct bootable volume on the SAN and proceed with the boot process.
Question 2 :-
An engineer discovers that the NPV (Network Port Virtualization) or NPIV (N-Port ID Virtualization) uplink is experiencing a heavy load. To address this issue, the engineer plans to add more uplinks to improve performance.
What will happen when these new uplinks are added to the uplink configuration?
Answer Options:
A. Only new connections automatically use the new uplinks.
B. Paths must be defined before new connections use the new uplinks.
C. All connections must be reset before the new uplinks are used.
D. New and existing connections automatically use the new uplinks.
Correct Answer:
D. New and existing connections automatically use the new uplinks.
Explanation:
In a networking environment where Network Port Virtualization (NPV) or N-Port ID Virtualization (NPIV) is implemented, uplinks are responsible for carrying data between network devices such as switches, servers, or storage systems. When an uplink experiences heavy load due to high traffic, the engineer may consider adding more uplinks to balance the load and improve performance.
When new uplinks are added in such configurations, the typical behavior is that both new and existing connections will automatically begin using these new uplinks, assuming the network design and protocols are correctly configured to allow such dynamic adjustments. Here’s a breakdown of why Option D is correct:
Automatic Load Balancing: In many modern network designs, especially those using NPV or NPIV, uplinks are configured to handle load balancing automatically. This means that once new uplinks are added, the network protocol (like FCoE, FC, or Ethernet) can seamlessly distribute the load across both the existing and new uplinks without requiring manual intervention.
No Need for Path Definition or Reset: Unlike traditional methods where paths may need to be manually defined or connections might need to be reset for new resources to be used, modern NPIV/NPV configurations typically handle these changes automatically. The protocols used for network management and optimization ensure that the existing traffic is re-routed to the newly added uplinks as needed.
Network Protocols and Virtualization Support: Both NPV and NPIV support virtualizing network ports and can automatically detect available uplinks and reroute traffic efficiently. Therefore, as long as the new uplinks are correctly configured and part of the same network or storage fabric, both existing and new connections will begin using them without disruption.
Incorrect Answers and Why:
A. Only new connections automatically use the new uplinks: This is incorrect because, in most cases, existing connections also benefit from the newly added uplinks. They are automatically rerouted by the network without requiring the creation of new connections.
B. Paths must be defined before new connections use the new uplinks: This option would be relevant in specific, older network configurations where manual intervention is needed. However, in most modern NPIV/NPV setups, paths do not need to be manually defined for new uplinks to be used automatically.
C. All connections must be reset before the new uplinks are used: Resetting connections is typically unnecessary in an optimized NPV/NPIV network environment. The system should handle the transition smoothly without resetting active connections.
In conclusion, the most efficient network setups today automatically handle load balancing when new uplinks are added, allowing both new and existing connections to benefit from the improved infrastructure without requiring any manual resets or path definitions.
Question 3 :-
An engineer is troubleshooting a failed Data Center Bridging Exchange (DCBX) negotiation between a server and a Cisco Nexus switch.
What action should the engineer take to ensure that DCBX can successfully negotiate between the devices?
A. Enable Enhanced Transmission Selection (ETS).
B. Enable Priority Flow Control (PFC).
C. Enable Cisco Discovery Protocol (CDP).
D. Enable Link Layer Discovery Protocol (LLDP).
Answer:
D. Enable Link Layer Discovery Protocol (LLDP).
Explanation:
The Data Center Bridging Exchange (DCBX) is a protocol used to exchange configuration information, such as Quality of Service (QoS) parameters, between devices in a Data Center Bridging (DCB)-enabled network. DCBX is particularly important in Data Center environments where reliable and efficient Ethernet transport is required, especially for applications like storage and high-performance computing.
When a DCBX exchange fails, it usually means that the devices are not correctly communicating the necessary configuration information to enable efficient traffic management. In this case, enabling the correct protocol for device communication can solve the problem.
The correct action to ensure DCBX functions as expected is to enable LLDP (Link Layer Discovery Protocol). LLDP is a widely used protocol that allows network devices to advertise their identity, capabilities, and other relevant information. LLDP is the foundation for DCBX exchanges, as it allows devices to exchange information about supported features such as Priority Flow Control (PFC) and Enhanced Transmission Selection (ETS), both of which are required for DCB functionality.
In contrast, the other options are less relevant in this context:
Option A (Enable ETS): Enhanced Transmission Selection (ETS) is a mechanism for managing bandwidth allocation in a DCB-enabled network. However, enabling ETS alone does not facilitate the negotiation of DCBX configuration parameters. ETS must be supported and negotiated via DCBX, but LLDP is needed to start that negotiation.
Option B (Enable PFC): Priority Flow Control (PFC) is used to prevent packet loss by pausing traffic at the Ethernet link level. While PFC is important in DCB, it relies on proper DCBX negotiation, which cannot occur without LLDP.
Option C (Enable CDP): Cisco Discovery Protocol (CDP) is a proprietary protocol used for device discovery in Cisco networks. While CDP is similar to LLDP, it is not used for DCBX exchanges. DCBX requires LLDP for configuration exchanges between devices.
To summarize, enabling LLDP ensures that the devices can correctly exchange the necessary DCBX parameters, facilitating a successful negotiation and ensuring that DCB features like PFC and ETS function as intended.
Question 4 :-
A Cisco Nexus Series interface has been placed in an "errdisabled" state with the error message "DCX-No ACK in 100 PDUs". What is the most likely cause of this error?
A. The host has not responded to the Control Sub-TLV DCBX exchanges of the switch.
B. The acknowledgement number in the server response has not incremented for 100 exchanges.
C. Cisco Discovery Protocol (CDP) is disabled on the switch.
D. Link Layer Discovery Protocol (LLDP) is disabled on the switch.
Answer:
A. The host has not responded to the Control Sub-TLV DCBX exchanges of the switch.
Explanation:
In a Cisco Nexus Series switch, the error message "DCX-No ACK in 100 PDUs" typically indicates a problem related to Data Center Bridging Exchange (DCBX) messages, specifically around a failure in the negotiation of Data Center Bridging capabilities between the switch and a connected host. The issue arises during the process where the switch sends out DCBX frames, and the host fails to acknowledge the control messages.
Here’s a breakdown of what happens:
DCBX Protocol: Data Center Bridging (DCB) is a set of standards that improves Ethernet's reliability and performance in data center networks. It uses protocols such as DCBX to facilitate communication between network devices and hosts to agree on parameters like traffic prioritization and congestion management. These settings ensure optimal performance for storage and high-priority traffic.
Control Sub-TLV (Type-Length-Value) Exchanges: When DCBX is used, the switch and host exchange information to negotiate various settings. The switch sends these control messages, which include details such as priority levels, bandwidth requirements, and more. The host should acknowledge these messages to confirm the settings. If the host fails to respond or the response is delayed beyond acceptable thresholds, the interface is placed in an "errdisabled" state to prevent network instability.
Error Message – "DCX-No ACK in 100 PDUs": This message indicates that the switch sent out 100 Protocol Data Units (PDUs) expecting an acknowledgment (ACK) from the host. However, it did not receive a timely acknowledgment from the host. As a result, the switch disables the interface to prevent any further miscommunication or potential network issues.
Cause of the Error: The most likely reason for this error is that the host did not respond to the DCBX exchanges sent by the switch. This could be due to a misconfiguration on the host, such as DCBX being disabled or a software issue preventing the acknowledgment from being sent.
Other Options:
Option B (acknowledgment not incrementing for 100 exchanges) refers to a potential issue in the acknowledgment process, but the core issue described is the lack of an ACK response.
Option C (Cisco Discovery Protocol disabled) is irrelevant because CDP is unrelated to DCBX.
Option D (LLDP disabled) is also irrelevant. While LLDP is used for similar discovery functions, DCBX operates separately and is not dependent on LLDP being enabled or disabled.
Therefore, the correct answer is A, indicating a failure in the exchange of control messages between the switch and host.
Question 5 :-
A Fibre Channel interface on a Cisco Nexus 5000 Series Switch is experiencing bit errors, leading to the automatic disabling of the interface. Before the root cause of the issue can be determined, a temporary workaround is required to prevent this issue from recurring.
Which of the following actions would prevent the interface from being disabled due to bit errors?
A. Verify that the SFPs are supported.
B. Change the SFP to operate at 4 Gbps instead of 2 Gbps.
C. Run the shutdown and then no shutdown commands on the interface.
D. Run the switchport ignore bit-errors command on the interface.
Answer:
D. Run the switchport ignore bit-errors command on the interface.
Explanation:
In Fibre Channel networks, bit errors on an interface can disrupt communication, causing the switch to disable the interface as a protective measure. The Cisco Nexus 5000 Series Switch, in particular, uses Fibre Channel interfaces for storage-area network (SAN) connectivity, which relies on accurate, error-free data transmission. When bit errors are detected, the interface is automatically shut down to prevent further disruption of the network.
To temporarily prevent the interface from being disabled while the root cause of the bit errors is investigated, one of the most effective actions is to apply the switchport ignore bit-errors command. This command allows the switch to ignore bit errors and continue operation, even when errors are detected. Although this does not resolve the underlying cause of the bit errors, it prevents the interface from being disabled immediately, allowing for troubleshooting or other temporary measures to take place.
Let's evaluate each option in detail:
A. Verify that the SFPs are supported:
While ensuring the proper SFP (small form-factor pluggable) modules are used is important for optimal performance, this action does not directly prevent the interface from being disabled due to bit errors. Verifying compatibility may help identify long-term fixes but won't address the immediate need for a workaround.B. Change the SFP to operate at 4 Gbps instead of 2 Gbps:
Changing the SFP speed might not solve the issue if bit errors are already present. In fact, mismatched speeds between devices can often lead to communication errors. Unless the root cause of the errors is related to an SFP speed mismatch, changing the speed is unlikely to provide a quick fix.C. Run the shutdown and then no shutdown commands on the interface:
Running the shutdown and no shutdown commands may temporarily bring the interface back online, but it does not address the core issue of bit errors. This action is more of a reset and may not prevent the interface from being disabled again once the errors reoccur.D. Run the switchport ignore bit-errors command on the interface:
This option directly addresses the problem by instructing the switch to disregard the bit errors, thus preventing the automatic interface shutdown. This is a temporary workaround that will keep the interface active while further investigation is conducted to identify the root cause of the errors.
In conclusion, the most effective temporary workaround is to run the switchport ignore bit-errors command. This command ensures that the interface remains active despite the presence of bit errors, allowing for continued operations and troubleshooting. However, it’s important to note that this is only a temporary solution. The underlying cause of the bit errors, such as faulty hardware, signal interference, or incorrect configuration, must be investigated and resolved for a permanent fix.
Question 6:-
A fabric interconnect fails to boot, and the console displays the loader prompt. Which two actions should be taken to resolve the issue? (Choose two.)
A. Load an uncorrupted bootloader image.
B. Load an uncorrupted kickstart image.
C. Reconnect Layer 1 and Layer 2 cables between the fabric interconnects.
D. Reformat the fabric interconnect.
E. Load the correct version of the boot image.
When a fabric interconnect fails to start and the console displays the loader prompt, it generally indicates that the system cannot locate or load the required software to boot fully. In this scenario, two key actions can help resolve the issue.
Correct Answers:
A. Load an uncorrupted bootloader image.
E. Load the correct version of the boot image.
Explanation:
When a fabric interconnect fails to start, it usually goes into a "loader" state where it waits for a valid boot image to be loaded. The loader prompt is indicative of the system not finding a valid boot image or being unable to load the necessary components for booting. Here’s why the two correct actions resolve this issue:
A. Load an uncorrupted bootloader image:
The bootloader image is responsible for initializing the hardware and loading the operating system on the fabric interconnect. If the bootloader image is corrupted, it will prevent the system from starting. In such cases, loading an uncorrupted version of the bootloader image can restore functionality. This image is typically stored in non-volatile memory and needs to be verified or reloaded if corruption occurs.
E. Load the correct version of the boot image:
In addition to the bootloader, the fabric interconnect requires a correct and compatible version of the boot image (operating system). If the boot image is either missing or incompatible with the current hardware or firmware, the system will fail to boot. Ensuring that the correct version of the boot image is loaded is critical for proper startup. This action typically involves specifying the correct image file through the loader prompt to resume the boot process.
Why the Other Options Are Incorrect:
B. Load an uncorrupted kickstart image:
The kickstart image is a crucial component for the Cisco UCS system, but if the fabric interconnect is unable to even get past the loader prompt, it indicates a problem with either the bootloader or the boot image, not the kickstart image. The kickstart image is important once the system is booting, but it won’t resolve an issue where the system cannot load the boot image.C. Reconnect Layer 1 and Layer 2 cables between the fabric interconnects:
Layer 1 and Layer 2 connectivity issues may cause communication problems in a fabric interconnect setup, but they would not prevent the system from booting up in the first place. The issue described here is related to the internal boot process of the system, not connectivity between interconnects.D. Reformat the fabric interconnect:
Reformatting the fabric interconnect might be a drastic solution and is typically not necessary unless there is irreparable corruption or configuration issues. Reformatting would wipe out all configurations, which is generally not the first action to take when troubleshooting boot issues. It should be considered only after other recovery methods have been exhausted.
By addressing the bootloader and boot image directly, the issue can usually be resolved without the need for reformatting or dealing with connectivity issues.
