Cisco
300-610 · Question #135
300-610 Question #135: Real Exam Question with Answer & Explanation
The correct answer is B: Enable the FCoE class in QoS on Cisco Nexus 5672UP switches.. The Cisco Nexus 5672UP switches require explicit QoS configuration for handling FCoE traffic - Enabling the FCoE class within QoS policies ensures that FCoE traffic is treated as a no-drop class and prioritized appropriately. - Proper QoS classification allows the switch to handl
Question
A company has added a new FCoE storage array to increase the performance of datastore access for end users. This storage array is directly connected to the Cisco Nexus 5672UP switches using four 10G port-channel interfaces. After deployment, the end users fail to access the datastore compared to the older solution. A network engineer verified the port-channel interface and finds that the congestion occurs when PFC frames are generated at the FCoE ingress interface. Which action must be taken to resolve the congestion issue?
Options
- AReserve bandwidth for FCoE VLAN on the port-channel interface connected with storage.
- BEnable the FCoE class in QoS on Cisco Nexus 5672UP switches.
- CIncrease the queuing buffer in the port-channel interface connected to the storage array.
- DAdd an additional FCoE VLAN to the SAN network.
Explanation
- The Cisco Nexus 5672UP switches require explicit QoS configuration for handling FCoE traffic - Enabling the FCoE class within QoS policies ensures that FCoE traffic is treated as a no-drop class and prioritized appropriately. - Proper QoS classification allows the switch to handle flow control frames like PFC without causing congestion and frame drops. - Reserving bandwidth or adding VLANs alone does not necessarily address the traffic classification and buffering required for lossless Ethernet needed by FCoE. - Increasing queuing buffer alone is not sufficient without the QoS policy enabling proper prioritization and lossless behavior. Supporting references indicate that enabling the FCoE class in the three types of QoS policies (classification, queuing, and scheduling) must be done before enabling FCoE on Cisco Nexus switches like the 5672UP to properly manage congestion and PFC behavior.
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