CompTIA Network+ (N10-009)Network ImplementationMedium
A company wants to combine four physical 1Gbps switch ports into a single logical interface providing both increased throughput and redundancy between two switches. Which technology should be configured?
- AHot Standby Router Protocol
- BSpanning Tree Protocol
- CLink Aggregation Control Protocol
- DVirtual Router Redundancy Protocol
Show answer & explanationAnswer & explanation
Correct answer: C. Link Aggregation Control Protocol
Link Aggregation Control Protocol (LACP), defined in IEEE 802.3ad, dynamically bundles multiple physical links into one logical link, increasing bandwidth and providing failover redundancy. STP prevents loops but doesn't combine links, and VRRP/HSRP provide gateway redundancy, not port bundling.
Why the other options are wrong
- A. HSRP is Cisco's router redundancy protocol, not a link aggregation technology.
- B. STP prevents switching loops but does not aggregate multiple links into one.
- D. VRRP provides first-hop router redundancy, unrelated to switch port bundling.
Link Aggregation (LACP)
IEEE 802.3ad standard protocol that combines multiple physical network links into a single logical link, increasing bandwidth and providing redundancy.
- Also called EtherChannel (Cisco) or port channel
- Requires matching speed/duplex on all bundled ports
- Provides both increased throughput and failover
Memory trick: 'Many links become one'—LACP bundles the bandwidth.