What are the ACI L2 connectivity options?

(1) Extend the application EPG out. (2) Extend the BD out (L2Out).

Cisco ACI L2Out or EPG Out? Design Decisions & Use Cases

Understanding the differences between the L2Out and the EPG Out is essential when extending the Cisco ACI L2 connectivity outside the fabric.
Therefore, this blog breaks down the technical details, ideal use cases, and configuration tips to help you deploy the right solution in your Cisco ACI environment.

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Summary

Cisco ACI L2 external network connectivity options: (1) Extend the application EPG out. (2) Extend the BD out.
When using the EPG out method, STP TCNs from the external Layer-2 switch may impact the ACI internal EPs in the same VLAN.
On the other hand, when using the BD out (L2Out) method, STP TCNs from the external Layer-2 switch do not impact the ACI internal EPs.
Cisco APIC Layer 2 Networking Configuration Guide.

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Salman Alhiary Expert Network Consultant

In the networking field since 2010, 2× CCIE (ENT & DC), and founder of LearnWithSalman—specializes in Cisco Data Center networking and automation. A former Cisco TAC engineer and now an Expert Professional Services consultant, he delivers lab-first tutorials, deep templates, and repeatable playbooks through his courses and technical blog, all built from real enterprise projects.

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