Layer 2 Only ACI

[eugenia]

Hi,  I have a client who is insanely busy and getting the IT Team trained to support ACI is going to be challenging (more than usual).  We are discussing design options and Im wondering if a Layer 2 only design might be best for them.  

Would love to get some feedback from the community on this.  This is a small fabric (2-4 leafs max).

We want to use contracts to control traffic between EPGs.  All Layer 4-7 services will live outside the fabric on a classical ethernet core.  The compute environment is connected to non ACI switches and so will not be directly connected to the fabric (Not UCS/FIs) rather 3rd party switches will connect to the ACI leaf switches.

A Layer 2 only design where all the routing and SVIs would live on the classical ethernet core "sounds" simpler and more familiar to operate Day 2 but I have concerns about tradeoffs.

Comments, suggestions, guidance, and "gotchas" would be very welcome!

[Oliver Qiu]

Thanks for raising your questions in ACI Community. This is a very common use case for L2 networking.

You could refer to Cisco APIC Layer 2 Networking Configuration Guide.

https://www.cisco.com/c/en/us/td/docs/dcn/aci/apic/5x/layer-2-configuration/cisco-apic-layer-2-networking-configuration-guide-52x/cisco-aci-layer-2-and-layer-3-forwarding-52x.html

About L2 Design you can refer to Design Guide - Bridge Domain Design Considerations

https://www.cisco.com/c/en/us/td/docs/dcn/whitepapers/cisco-application-centric-infrastructure-design-guide.html#BridgeDomainDesignConsiderations

And you invite your customer join ATX session or ACI Accelerator and you can also learn more about Cisco ACI through our live Ask the Experts (ATXs) session. Check out the ATXs Resources [ https://community.cisco.com/t5/data-center-and-cloud-knowledge/cisco-aci-ask-the-experts-resources/ta-p/4394491] to view the latest schedule for upcoming sessions, as well as the useful references, e.g. online guides, FAQs.

If you find my reply solved your question or issue, kindly click the 'Accept as Solution' button and vote it as helpful.

[LearnWithSalman]

Cisco ACI L2 external network connectivity options: (1) Extend the application EPG out. (2) Extend the BD out. For more info, I explained it in my blog Cisco ACI L2 Connectivity Guide: EPG Out vs. BD Out (L2Out).