Which ACI VPC Protection Type Pairs Odd and Even Leaf Switches?
A Cisco ACI fabric has 10 standalone leaf switches. The requirement is for the APIC to select the odd switches as a VPC group and select even switches as another VPC group automatically. Which VPC protection type must be configured to accomplish this goal?
Community Votes
67% of anonymous learners picked answer C. Votes are pick records left by other test-takers — they are not the verified answer.
Community Insight
The question tests whether you can map an odd/even pairing outcome onto the correct VPC protection type on the vpc domain, and the trap is confusing reciprocal with consecutive, which pairs neighbours instead (101-102, 103-104).
In Cisco ACI, the reciprocal VPC protection type makes APIC automatically pair discovered standalone leaves in a reciprocal pattern — odd with odd (101-103) and even with even (102-104) — which is exactly the odd/even grouping the question requires. This page confirms reciprocal as the correct answer over consecutive, explicit, and the nonexistent serial option.
The most common wrong pick is explicit, because candidates assume any non-obvious grouping must be hand-configured; explicit requires you to name the two leaf nodes yourself, so it does not satisfy the 'automatically' requirement.
Community Discussion (3 comments)
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Expert Analysis
Why the Answer Is Correct
Inside the VPC domain configuration on APIC, the reciprocal protection type tells the controller to pair every discovered leaf with a partner such that odd-numbered switches pair with odd-numbered switches and even with even — for example 101-103 and 102-104. The question states that APIC must select the odd switches as one VPC group and the even switches as another automatically, which is precisely the reciprocal pattern and needs no manual node list. The CLI context help quoted by a community member shows the exact semantics: "reciprocal Pair all discovered leaves reciprocally e.g. 101-103, 102-104". Because the pairing is derived automatically from the leaf numbering, reciprocal satisfies both the automatic requirement and the odd/even split. This is why option C is the answer the wording points to.Why the Other Options Are Wrong
Consecutive is the near-miss distractor: it also pairs leaves automatically but in adjacent order (101-102, 103-104), which mixes odd and even leaves into the same VPC group, so it cannot produce an all-odd group and an all-even group. Explicit does give you full control, but it requires an administrator to specify the two leaf nodes by hand, contradicting the "automatically" condition in the scenario. Serial is not a valid VPC protection type on the APIC VPC domain at all, so it can be eliminated on sight. Only reciprocal produces two distinct odd/even groups without operator input.Community Comment Notes
As freekaz noted, the CLI help for the VPC domain shows the three real protection types — consecutive, explicit, and reciprocal — with reciprocal pairing "all discovered leaves reciprocally e.g. 101-103, 102-104". samfab summarised the behaviour simply as "Automatically pairs switches in a reciprocal manner", reinforcing that no manual node selection is involved. mdriraa answered explicit but linked the Cisco ACI design guide whitepaper, which is the authoritative source for how APIC forms VPC groups; the document's description of reciprocal pairing supports the majority view. The 67-to-33 vote split also reflects how often candidates over-think this item and reach for explicit.Official Reference
Exam Strategy
Memorise the three VPC protection keywords with a one-line signature each: consecutive = adjacent pairs, reciprocal = odd/even pairs, explicit = manually named pairs. If the stem says "automatic" and describes an odd/even split, reciprocal is the answer almost every time.
Frequently Asked Questions
Why is consecutive wrong for odd/even VPC grouping in ACI?
Consecutive pairs adjacent leaves such as 101-102 and 103-104, so each VPC group would contain one odd and one even switch instead of two odd or two even leaves.
Does explicit VPC protection meet the automatic requirement?
No. Explicit requires the administrator to name the two leaf nodes that form each VPC pair, so APIC does not select the groups automatically as the scenario demands.