Cisco ACI and moving layer 3 into the fabric

[trondaker]

Hi,

Were looking into the least troublesome route for moving layer 3 into the ACI fabric. However, the border leaves cannot participate in a HSRP-group with the old Nexus environment, so how do people do this? We have two data centers with OTV between, and right now its looking like the only move is a big bang with turning off layer 3 on the Nexus-side, and enabling unicast routing on the ACI-side - obviously with downtime. Is there no smoother way of doing this? This must be a neglected area migration-wise from Cisco if not?

[Manuel Velasco]

Hi Trondaker,

Starting with version 2.2(1n) The ACI supports HSRP

Cisco ACI HSRP

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/kb/b_Cisco_APIC_HSRP.html

[trondaker]

Hi Manuel,

Thanks for your reply! Im not sure if this quite solves our problem, because as a start were letting all VLANs flow into ACI via extended bridge domains, so we have layer 2 between old and new. Layer 3 is still on 7k, and no unicast routing in ACI. If the HSRP in ACI is only available on routed or subinterfaces, doesnt that mean that my link into ACI can no longer be a pure layer 2? How can we maintain the layer 2 flow between old and new, and seamlessly migrate layer 3 into ACI with HSRP?