When is GLBP preferred over HSRP?

Question

Options

• AWhen the gateway routers are a mix of Cisco and non-Cisco routers.
• BWhen encrypted hellos are required between gateways in a single group.
• CWhen the traffic load needs to be shared between multiple gateways using a single virtual IP.
• DWhen clients need the gateway MAC address to be the same between multiple gateways.

• A
  8% (3)
• B
  3% (1)
• C
  86% (32)
• D
  3% (1)

Explanation

GLBP vs HSRP: Load Sharing with a Single Virtual IP

GLBP (Gateway Load Balancing Protocol) is preferred over HSRP specifically when you need active load balancing across multiple gateways while still presenting a single virtual IP address to clients - each gateway in a GLBP group gets its own virtual MAC address, allowing traffic to be distributed among all active routers simultaneously, unlike HSRP where only one router is active at a time.

Why the distractors are wrong:

• A is wrong because GLBP is a Cisco-proprietary protocol, just like HSRP - if you need a mixed-vendor environment, you'd use the open-standard VRRP instead.
• B is wrong because encrypted hellos are a feature consideration available in HSRP version 2, not a distinguishing reason to choose GLBP over HSRP.
• D is wrong because requiring the same MAC address across gateways describes HSRP/VRRP behavior (one virtual MAC), not GLBP, which actually assigns different virtual MACs per gateway to enable load balancing.

Memory Tip: Think of GLBP as "G = Go all at once" - all gateways are actively forwarding traffic under one virtual IP, while HSRP keeps extras on standby. If you see "load sharing + single VIP," think GLBP.

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