hardMultiple ChoiceObjective-mapped
300-410 Practice Question: CoPP rate-limit is impacting legitimate traffic…
CoPP rate-limit is impacting legitimate traffic due to route summarization. Router R1 has:
access-list 100 permit ip 10.0.0.0 0.0.3.255 any
! class-map match-all COPP-CLASS match access-group 100 ! policy-map COPP-POLICY
class COPP-CLASS
police 10000 conform-action transmit exceed-action drop ! control-plane service-policy input COPP-POLICY !
router eigrp 100 network 10.0.0.0
!
interface GigabitEthernet0/0 ip summary-address eigrp 100 10.0.0.0 255.255.252.0
! R2 (10.0.1.1) sends EIGRP packets to R1, but they are being dropped. What is the root cause?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The CoPP policy matches EIGRP traffic from the summarized range and polices it, causing EIGRP packets to be dropped.
The CoPP policy matches traffic from 10.0.0.0/22 and polices it to 10 kbps. EIGRP packets from R2 (10.0.1.1) are within this range and are subject to policing. If the EIGRP traffic rate exceeds 10 kbps, packets are dropped, causing neighbor flapping. The summary route itself does not cause the drop, but the CoPP policy inadvertently includes EIGRP traffic. The fix is to create a separate class for EIGRP or adjust the ACL.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The CoPP policy matches EIGRP traffic from the summarized range and polices it, causing EIGRP packets to be dropped.
Why this is correct
EIGRP packets are within the ACL range and are rate-limited.
- ✗
The summary route causes EIGRP to send packets to the control plane at a high rate, exceeding the policer.
Why it's wrong here
The summary does not increase packet rate.
- ✗
EIGRP is not enabled on the interface, so packets are dropped.
Why it's wrong here
EIGRP is enabled.
- ✗
The control-plane policy is applied in the wrong direction.
Why it's wrong here
Input direction is correct for incoming packets.
Visual reference
Quick reference
Routing Protocol Comparison
| Protocol | Metric | Max Hops | Algorithm | Type |
|---|---|---|---|---|
| RIP v2 | Hop count | 15 | Bellman-Ford | Distance vector |
| OSPF | Cost (bandwidth) | Unlimited | Dijkstra (SPF) | Link state |
| EIGRP | Composite metric | Unlimited | DUAL | Hybrid |
| IS-IS | Cost | Unlimited | Dijkstra | Link state |
| BGP | Policy / attributes | Unlimited | Path vector | Path vector |
RIP's 15-hop limit makes it unsuitable for large networks. OSPF and EIGRP dominate modern enterprise deployments.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 300-410 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 300-410 exam.