Which Protocol Gives This Redundancy?

About this interactive

From the lesson and the course so far: - **High availability** means redundancy at every level: power, cooling and internet links, equipment and its parts, links between devices, and services. Uptime is measured in nines: three nines is about 8.8 hours of downtime a year, five nines about 5 minutes. - **Spanning tree** keeps redundant links between switches but blocks loops, and brings a blocked link up when one fails. - **EtherChannel** bundles parallel links between two switches so all of them carry traffic, and survives losing one. - **Dynamic routing** (OSPF) finds another path between routers on its own. - **FHRP** covers what none of those do: the default gateway. Hosts point at a virtual IP that a standby device takes over if the active one fails.

What you'll learn

Choose the protocol that provides a kind of redundancy: spanning tree for loop-free redundant switch links, EtherChannel for bundled links between two switches, dynamic routing for alternate Layer 3 paths, and an FHRP for the default gateway
Explain why a network built for high availability needs redundancy at every level, including the first hop

Aligned to

Cisco CCNA

3.5 Describe the purpose, functions, and concepts of first hop redundancy protocols

2.5 Interpret basic operations of Rapid PVST+ Spanning Tree Protocol

2.4 Configure and verify Layer 2/Layer 3 EtherChannel (LACP)

Key terms

First Hop Redundancy Protocol: A category of protocols that provide default gateway redundancy by allowing multiple routers to share a single virtual IP address. If the active gateway fails, another router in the FHRP group takes over transparently without requiring client reconfiguration; examples include HSRP, VRRP, and GLBP.
High Availability: High Availability describes systems designed to operate continuously with minimal downtime, achieved through redundancy, failover clustering, and load balancing to meet the Availability pillar of the CIA triad.
Spanning Tree Protocol: A network protocol that prevents loops in Ethernet networks by creating a loop-free logical topology.
EtherChannel: Cisco's implementation of link aggregation that bonds multiple physical links into a single logical channel to increase bandwidth and redundancy.
Virtual IP Address: A shared IP address used by HSRP group members that endpoints use as their default gateway, allowing traffic to continue flowing if the active router fails.
Service Level Agreement: A formal agreement between a service provider and a service receiver that defines the expected level of service, including availability, performance, and security commitments.
Uptime: The amount of continuous time a network device or service has been running without interruption, often expressed as a percentage of total time available. High uptime percentages (such as 99.9%) indicate a reliable network, while planned and unplanned downtime reduces this figure.

Topics

High Availability Redundancy Fhrp Stp Etherchannel Dynamic Routing Interactive Categorize

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