One of the interesting design considerations when deploying FabricPath is where to put your layer 3 gateways (i.e. your SVIs). Some people opt for the spine layer (especially in smaller networks), some may choose to deploy a dedicated pair of leaf switches acting as gateways for all VLANs, or distribute the gateway function across multiple leaves. Whatever choice is made, there are a couple of challenges that some have come across.

As you may know, vPC+ modifies the behaviour of HSRP to allow either vPC+ peer to route traffic locally. This is certainly useful functionality in a FabricPath environment as it allows dual active gateways, however what if you want your default gateways on the Spine layer (where there are no directly connected STP devices, and therefore no real need to run vPC+)? What you end up with in this case is vPC+ running on your Spine switches in order to gain access to the dual active HSRP forwarding, but with no actual vPC ports on the switch. This works fine – but most people would prefer not to have vPC+ running on their Spine switches if they can avoid doing so.

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