About this interactive
From the lesson:
- **The virtual IP** is the hosts' default gateway. Two (or more) layer 3 devices share it; each also keeps a real address of its own.
- **Active and standby:** the active device answers ARP for the virtual IP with a virtual MAC. The standby exchanges hello packets with it and waits.
- **Failover:** when the hellos stop, the standby becomes active and answers for the same IP and MAC. Hosts change nothing; the access switches just learn the gateway MAC on a new port.
- **The protocols:** HSRP, HSRPv2 and GLBP are Cisco proprietary; VRRP is an open standard.
What you'll learn
- Predict how a first hop redundancy protocol behaves: hosts use the virtual IP, the active device answers for it, and the standby takes over when hellos stop
- Explain why the failover needs no change on the hosts, and name which FHRPs are Cisco proprietary and which is an open standard
Aligned to
Cisco CCNA
3.5
Describe the purpose, functions, and concepts of first hop redundancy protocols
Key terms
- First Hop Redundancy Protocol
FHRP
- 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.
- 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.
- Default Gateway
- The router that a device uses to send traffic to destinations outside its local network.
- Hot Standby Router Protocol
HSRP
- A Cisco proprietary FHRP where a group of routers share a virtual IP address and MAC address, with one active router forwarding traffic while standby routers monitor and take over if the active router fails. HSRP provides transparent default gateway redundancy for end hosts without requiring any client-side configuration.
- Virtual Router Redundancy Protocol
VRRP
- An open-standard FHRP defined in RFC 5798 that allows multiple routers to share a virtual IP address as a default gateway, with one master router actively forwarding traffic and backup routers ready to take over if the master fails. VRRP is the vendor-neutral alternative to Cisco's proprietary HSRP.
- Gateway Load Balancing Protocol
GLBP
- A Cisco proprietary FHRP that provides both gateway redundancy and load balancing by allowing multiple routers to actively forward traffic for a single virtual IP address.
Topics
Fhrp
Virtual Ip
Failover
Default Gateway
Hsrp
Vrrp
Interactive
Predict
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