300-420 Question 256
Single answerA network administrator is tasked with implementing a traffic policing policy on a Cisco router to limit traffic from a specific department to 10 Mbps. The administrator wants to ensure that any traffic exceeding the defined rate is dropped without affecting the guaranteed rate for compliant traffic. Which of the following configuration choices should the administrator make to meet this requirement?
- A
Configure a single-rate two-color traffic policing policy with a committed information rate (CIR) of 10 Mbps and exceed-action set to drop.
- B
Configure a single-rate three-color traffic policing policy with a committed information rate (CIR) of 10 Mbps, exceed-action set to transmit, and violate-action set to drop.
- C
Configure a dual-rate three-color traffic policing policy with a committed information rate (CIR) of 10 Mbps and a peak information rate (PIR) of 15 Mbps, with exceed-action set to drop.
- D
Configure a dual-rate two-color traffic policing policy with a committed information rate (CIR) of 10 Mbps, a peak information rate (PIR) of 15 Mbps, and exceed-action set to transmit.
Show answer and explanation
Correct answer: A
Explanation
Policing is used to enforce traffic limits by dropping or remarking packets that exceed the configured rate. In this scenario, the administrator needs a strict 10 Mbps limit with no allowance for excess traffic. A single-rate two-color policing policy is the simplest and most effective configuration for this use case, as it ensures that all traffic above the CIR of 10 Mbps is immediately dropped.
- A. Correct.
This option is correct because a single-rate two-color policing policy with exceed-action set to drop ensures that traffic above 10 Mbps is immediately dropped while guaranteeing the CIR of 10 Mbps for compliant traffic.
- B. Incorrect.
This option is incorrect because a single-rate three-color policy would allow for traffic exceeding the CIR to potentially be transmitted or marked, which does not fully meet the requirement of dropping excess traffic.
- C. Incorrect.
This option is incorrect because a dual-rate three-color policy introduces a peak information rate (PIR), which is not necessary for the stated requirements. The goal is to strictly enforce a 10 Mbps limit without considering a peak rate.
- D. Incorrect.
This option is incorrect because a dual-rate two-color policy with exceed-action set to transmit would allow excess traffic to pass, violating the requirement of dropping all traffic above 10 Mbps.