TMP Network Design & Optimization 3 — Questions and Answers
Question 1: A telecom engineer observes high packet loss on a fiber link after a storm. Which diagnostic step should be performed FIRST?
- Replace the fiber cable immediately
- Run an OTDR test to locate the fault (Correct answer)
- Reboot the connected routers
- Increase transmit power on the transceiver
Correct answer: Run an OTDR test to locate the fault
An Optical Time Domain Reflectometer (OTDR) test pinpoints the exact location and nature of a fiber fault without requiring physical cable access.
Question 2: Which network design principle minimizes the blast radius of a failure by dividing large Layer 2 domains?
- Spanning Tree Protocol tuning
- VLAN segmentation (Correct answer)
- Link aggregation
- Port mirroring
Correct answer: VLAN segmentation
VLANs create separate broadcast domains, so a broadcast storm or failure in one VLAN does not propagate to others.
Question 3: A company's WAN link is at 95% utilization. Before purchasing more bandwidth, which optimization should be evaluated first?
- Deploy a content delivery network
- Implement WAN optimization with data deduplication and compression (Correct answer)
- Increase MTU on the WAN interface
- Switch from OSPF to BGP
Correct answer: Implement WAN optimization with data deduplication and compression
WAN optimization technologies like deduplication and compression can reduce effective traffic volume by 50–80%, often deferring costly bandwidth upgrades.
Question 4: In BGP, what is the effect of prepending your own AS number multiple times to an advertised prefix?
- Increases the prefix's local preference
- Makes the path appear longer to external peers, discouraging inbound traffic via that path (Correct answer)
- Reduces the MED value for the prefix
- Forces traffic to use that path as primary
Correct answer: Makes the path appear longer to external peers, discouraging inbound traffic via that path
AS path prepending artificially lengthens the AS path, causing external BGP peers to prefer shorter paths via other providers.
Question 5: Which technology is used to aggregate multiple physical links into a single logical high-bandwidth connection between switches?
- Spanning Tree Protocol
- Link Aggregation Control Protocol (LACP) (Correct answer)
- Virtual Router Redundancy Protocol (VRRP)
- Multiprotocol Label Switching (MPLS)
Correct answer: Link Aggregation Control Protocol (LACP)
LACP (IEEE 802.3ad) dynamically negotiates and maintains link aggregation groups, combining bandwidth and providing redundancy.
Question 6: A network manager needs to ensure that a mission-critical application receives guaranteed bandwidth regardless of other traffic. Which QoS mechanism is MOST appropriate?
- Best-effort delivery
- Traffic policing
- Committed information rate (CIR) with guaranteed queuing (Correct answer)
- Random Early Detection (RED)
Correct answer: Committed information rate (CIR) with guaranteed queuing
A guaranteed queue backed by a CIR reserves a minimum amount of bandwidth for the application even during periods of network congestion.
Question 7: What is the purpose of route summarization (route aggregation) in a large enterprise network?
- To encrypt routing updates between peers
- To reduce routing table size and control update propagation (Correct answer)
- To enable multicast routing
- To prevent BGP route flapping
Correct answer: To reduce routing table size and control update propagation
Summarizing multiple specific routes into a single aggregate prefix reduces routing table size, conserves memory, and limits the propagation of topology changes.
TMP Network Design & Optimization 3
A telecom engineer observes high packet loss on a fiber link after a storm.
Which diagnostic step should be performed FIRST?