How Can EPG-12 and EPG-10 Share VLAN-12 on the Same ACI Leaf?
An engineer configures port-12 on Leaf-101 and Leaf-102 to connect to a new server called SVR-12. This server will belong to a new EPG-12 and needs to use Encapsulation VLAN-12. An already existing server, which is named SVR-10, is also connected to the same leaf switches. SVR-10 belongs to EPG-10 and also uses Encapsulation VLAN-12. Which step must the engineer take to configure connectivity for SVR-12 and EPG-12?
Community Votes
100% of anonymous learners picked answer B. Votes are pick records left by other test-takers — they are not the verified answer.
Community Insight
It tests ACI's rule for duplicate VLAN encapsulation on one leaf: the EPGs need different bridge domains, different ports, and port-local VLAN scope.
Two ACI EPGs, EPG-10 and EPG-12, can reuse VLAN-12 encapsulation on Leaf-101 and Leaf-102 only after port-local VLAN scope is enabled. This page confirms port-local VLAN scope (B) as the required step for SVR-12 connectivity.
The tempting wrong answer is A — placing EPG-12 in the same BD as EPG-10; Cisco instead requires EPGs that share an encapsulation to use different bridge domains.
Community Discussion (4 comments)
Comments & Corrections
No comments yet — spotted an error or have a note? Share it below.
Expert Analysis
Why the Answer Is Correct
In Cisco ACI, a VLAN encapsulation is normally unique per leaf switch, so EPG-12 and EPG-10 both using VLAN-12 on Leaf-101 and Leaf-102 would conflict by default. Cisco's Layer 2 configuration guide states that to deploy multiple EPGs with the same encapsulation on a single leaf, the EPGs must be associated with different bridge domains, deployed on different ports, tied to the same domain/VLAN pool containing that VLAN, and the ports must be configured with port-local VLAN scope. SVR-12 lands on port-12 while SVR-10 uses other ports, so enabling port-local VLAN scope on those leaf ports is exactly what allows VLAN-12 to be reused. Option B therefore resolves the encapsulation collision without changing the VLAN pool or the fabric-wide VLAN policy.Why the Other Options Are Wrong
Option A is the opposite of the Cisco rule: sharing the same bridge domain between EPG-12 and EPG-10 is precisely what is disallowed when both EPGs use the same encapsulation on one leaf, because overlapping subnets and forwarding domains would collide. Option C is irrelevant, since native VLAN is a trunk/untagged-frame concept and does not control ACI EPG encapsulation uniqueness. Option D addresses IP addressing, but ACI forwards traffic based on EPG and BD context, not on subnet membership, so moving SVR-12 to another subnet would not remove the duplicate VLAN-12 conflict on the leaf ports.Community Comment Notes
As prospio971 explained, the conflict exists because ACI by default forbids the same VLAN encapsulation for multiple EPGs on the same port or leaf, and port-local VLAN scope is the fix. ed27 quoted the Cisco guidelines directly, including "EPGs must be associated with different bridge domains" and "Ports must be configured with portLocal VLAN sco", which rules out option A and supports B. zelya19 also pointed to the official Cisco L2 networking configuration guide page for EPGs, and designated simply agreed that B is correct. The learner vote record here is unanimous for B, which matches the documented ACI behavior.Official Reference
Exam Strategy
When two ACI EPGs reuse one VLAN encapsulation, immediately look for the port-local VLAN scope requirement rather than a bridge-domain or IP change. Memorize the trio of conditions Cisco lists — different BDs, different ports, same VLAN-pool domain — and verify the port-level setting before answering.
Frequently Asked Questions
Why can't EPG-12 use the same bridge domain as EPG-10 when both use VLAN-12?
Cisco requires EPGs that share one VLAN encapsulation on a leaf to be in different bridge domains, so reusing EPG-10's BD would violate the duplicate-encapsulation guidelines.
Does disabling the native VLAN solve the duplicate VLAN-12 encapsulation conflict?
No. Native VLAN applies to untagged or trunk traffic, while the conflict here is about ACI EPG VLAN encapsulation uniqueness, which port-local VLAN scope resolves.