Implementing and Operating Cisco Enterprise Network Core Technologies (ENCOR) v1.2InfrastructureMedium
A network engineer is configuring a new Layer 3 routing switch to act as the default gateway for multiple VLANs. The requirement is to provide redundant default gateway functionality for end-user devices, ensuring high availability in case of a single device failure. Which First Hop Redundancy Protocol (FHRP) should be configured to meet this requirement, allowing for active/standby redundancy?
- AOSPF (Open Shortest Path First)
- BGLBP (Gateway Load Balancing Protocol)
- CPIM (Protocol Independent Multicast)
- DVRRP (Virtual Router Redundancy Protocol)
Show answer & explanationAnswer & explanation
Correct answer: D. VRRP (Virtual Router Redundancy Protocol)
VRRP provides active/standby redundancy for default gateways, where one router acts as the master and forwards traffic, while others remain in a standby state, taking over if the master fails. This fits the requirement for high availability through active/standby operation.
Why the other options are wrong
- A. OSPF is an interior gateway routing protocol used for exchanging routing information, not for providing first-hop redundancy.
- B. GLBP provides load balancing across multiple gateways, which is not strictly 'active/standby' for a single virtual gateway.
- C. PIM is a multicast routing protocol and has no function in providing default gateway redundancy.
First Hop Redundancy Protocol (FHRP)
A group of protocols used to provide default gateway redundancy for IP hosts on a shared LAN segment.
- Ensures continuous network access even if the primary gateway fails.
- Protocols include HSRP, VRRP, and GLBP.
- Transparent to end-user devices, which see a single virtual gateway address.
Memory trick: FHRP: Redundancy for Your First Hop.