In reply to Dibakar Sen.

Thanks for your question Dibakar.

Many customers have been concerned about integration issues with their existing networking equipment as they migrate to ACI. ACI does not require a greenfield environment. There are multiple ways of integrating with and migrating to ACI from any kind of existing network topology (ex: core/aggregation/access, vPC, VxLAN, etc).

In those mature production environments requiring additional capacity, new ACI pods are capable of being seamlessly interconnected with existing networks either by extending layer 2 VLAN’s or by interconnecting at layer 3 using standard route peering. Networks that require more granular segmentation and automation for layer 4-7 services can leverage an ACI as a data center policy engine connected to the existing networks. For those environments wanting to add full ACI policy capabilities without replacing the existing network, remote physical and virtual leaf switches can be added in an incremental fashion at the edge of the current network. For more information on types of integration, you can refer to this white paper.

As for Layer 4-7 devices, there are a number of open APIs that can be leveraged. OpFlex offers an API through which policy can be directly exchanged with an agent running on an L4-7 device. This allows the tightest level of integration with APIC. If OpFlex is not yet available on a device, there is also a device package API that leverages the existing APIs on L4-7 devices so they can be used in an unmodified manner with ACI. And of course, in the worst case, there is always the option of integrating directly with multiple management platforms to provide the proper networking within your environment. These may include automation and orchestration tools that take out the manual element of administration.

Many datacenters are migrating their DC networks to next generation switching and routing evolutions every 4-6 years on average. So while you may not be able to fully transition to an ACI design overnight, you may still head in that direction by integrating Nexus 9000 series switches into your current network design evolving to 10G, 40G and 100G while future proofing and making migration to ACI simpler later on.

If you would like more information on how to do this within your specific environment, please contact your Cisco Sales Engineer to figure out a design that will work best for you.