350-401 Question #31: Real Exam Question with Answer & Explanation

Question

Which behavior can be expected when the HSRP versions is changed from 1 to 2?

Options

• AEach HSRP group reinitializes because the virtual MAC address has changed.
• BNo changes occur because version 1 and 2 use the same virtual MAC OUI.
• CEach HSRP group reinitializes because the multicast address has changed.
• DNo changes occur because the standby router is upgraded before the active router.

Explanation

HSRP Version Change Behavior

When upgrading from HSRP version 1 to version 2, each HSRP group reinitializes because the virtual MAC address changes. HSRPv1 uses the OUI 0000.0C07.ACxx, while HSRPv2 uses 0000.0C9F.Fxxx - a completely different MAC range. This change forces all routers in the group to go through the election process again, causing a brief disruption as the new virtual MAC is established.

Why the distractors are wrong:

• B is incorrect because the two versions use different virtual MAC OUIs, not the same one.
• C is partially misleading - while the multicast address does change (v1 uses 224.0.0.2, v2 uses 224.0.0.102), the primary trigger for reinitialization is the virtual MAC change, not the multicast address change, making this answer incomplete and therefore wrong.
• D is incorrect because HSRP does not have an automatic sequencing mechanism that upgrades standby before active; both routers are affected by the version change.

Memory Tip: Think "MAC = Must Always Change" - when the MAC address changes in HSRP, the group must reinitialize because connected devices need to relearn which MAC address maps to the gateway IP.

No community discussion yet for this question.