350-501 Question #440: Real Exam Question with Answer & Explanation

Question

Refer to the exhibit Router R1 is configured with class map CE with match ip precedence critical to align with customer contract SLAs. The customer is sending all traffic from CE1 toward the FTP server with IP precedence 5. A network engineer must allow 10% of interface capacity on router R3. Which two actions must the engineer take to accomplish the task? (Choose two.)

Options

• AImplement a class map on R3 to match all packets with QoS IP precedence value 011.
• BImplement a class map on R1 to match all packets with QoS IP precedence value 100.
• CApply a policy map to R3 to reserve 10% of interface bandwidth.
• DApply a policy map to R1 to reserve the remaining 10% of interface bandwidth.
• EImplement a class map on R3 to match all packets with QoS IP precedence value 101.

Explanation

To allow 10% of interface capacity on router R3 for customer traffic marked with IP precedence 5, a class map must be created on R3 to match packets with IP precedence value 101, and then a policy map applied to an interface on R3 to reserve the specified bandwidth for this class.

Common mistakes.

• A. IP precedence value 011 corresponds to value 3 (Flash), not 5 (Critical), so a class map matching this would not identify the correct customer traffic.
• B. The requirement is to configure R3, not R1. Additionally, IP precedence value 100 corresponds to value 4 (Flash-override), not 5.
• D. The requirement is to configure R3, not R1, and reserving "remaining 10%" is not the specific task of allowing 10% capacity for a specific traffic class.

Concept tested. QoS IP Precedence matching and bandwidth reservation

Reference. https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/qos_mqc/configuration/xe-3s/qos-mqc-xe-3s-book/qos-mqc-overview.html

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