In this page you recommend to :
Enable Layer 3 routing between vPC peers over a separate layer 3 link
In this page : http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/mkt_ops_guides/513_n1_1/n5k_L3_w_vpc_5500platform.html#wp1014719
It is not recommended for Nexus 5K :
In some circumstances, you might consider having a separate link between the two vPC switches, either to carry non-vPC VLAN traffic or to form Layer 3 routing protocol peering. While this design is supported on the Cisco Nexus 7000 Series switch, it does not work on the Cisco Nexus 5000 Series switch. With the Cisco Nexus 5000 Series switch, we recommend that you use a vPC peer link for Layer 3 peering to carry both vPC and non-vPC VLAN traffic.
So what is the recommended design for 5K ?
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