Cisco Certified Support Technician (CCST) NetworkingNetworking FundamentalsHard
A network technician is configuring redundant connections between two core switches in a data center. If multiple active paths are allowed to exist simultaneously between switches, it can lead to broadcast storms, MAC address table instability, and multiple frame copies. Which protocol is designed to prevent these issues by logically blocking redundant paths while still allowing for physical redundancy?
- ASpanning Tree Protocol (STP)
- BLink Aggregation Control Protocol (LACP)
- CBorder Gateway Protocol (BGP)
- DVirtual Router Redundancy Protocol (VRRP)
Show answer & explanationAnswer & explanation
Correct answer: A. Spanning Tree Protocol (STP)
Spanning Tree Protocol (STP) is a Layer 2 protocol designed to prevent network loops in switched Ethernet networks. It achieves this by logically blocking redundant paths that could cause broadcast storms and MAC address table instability while maintaining physical redundancy for fault tolerance.
Why the other options are wrong
- B. LACP bundles multiple physical links into a single logical link to increase bandwidth and provide link redundancy, but it operates at Layer 2 and doesn't prevent broadcast storms from redundant paths between *different* switches if not properly configured with STP.
- C. BGP is a routing protocol used to exchange routing information between autonomous systems (Layer 3) on the internet, unrelated to Layer 2 loop prevention.
- D. VRRP provides default gateway redundancy for hosts on a subnet (Layer 3), not for preventing loops in switched networks (Layer 2).
Spanning Tree Protocol (STP)
Spanning Tree Protocol (STP) is a network protocol that builds a loop-free logical topology for Ethernet networks. It blocks redundant paths that could cause broadcast storms and MAC address table corruption, while still allowing for physical redundancy to provide fault tolerance.
- Prevents Layer 2 loops in switched networks.
- Logically blocks redundant paths.
- Ensures a single active path between any two network devices.
- Root bridge, designated ports, root ports, and blocked ports are key concepts.
Memory trick: STP: 'Stop' the loops, 'Protect' the network.