https://www.cisco.com/c/en/us/td/docs/solutions/CVD/Campus/cisco-sda-design-guide.html#VRF_Aware_Peer
CVD Author Here. Quoting directly from the CVD:
A fusion device can be either a true routing platform, a Layer 3 switching platform, or a firewall must meet several technological requirements. It must support:
● Multiple VRFs—Multiple VRFs are needed for the VRF-Aware peer model. For each VN that is handed off on the border node, a corresponding VN and interface is configured on the peer device. The selected platform should support the number of VNs used in the fabric site that will require access to shared services.
● Subinterfaces (Routers or Firewall)—A virtual Layer 3 interface that is associated with a VLAN ID on a routed physical interface. It extends IP routing capabilities to support VLAN configurations using the IEEE 802.1Q encapsulation.
● Switched Virtual Interfaces (Layer 3 switch)—Represents a logical Layer 3 interface on a switch. This SVI is a Layer 3 interface forwarding for a Layer 3 IEEE 802.1Q VLAN.
● IEEE 802.1Q—An internal tagging mechanism which inserts a 4-byte tag field in the original Ethernet frame between the Source Address and Type/Length fields. Devices that support SVIs and subinterfaces will also support 802.1Q tagging.
● BGP-4—This is the current version of BGP and was defined in RFC 4271 (2006) with additional update RFCs. Along with BGP-4, the device should also support the Multiprotocol BGP Extensions such as AFI/SAFI and Extended Community Attributes defined in RFC 4760 (2007).
These five technical requirements are supported on a wide range of routers, switches, and firewalls throughout the Cisco portfolio including Catalyst, Nexus, ASA, FTD, Aggregation Services Routers (ASRs), and Integrated Services Routers (ISRs) for both current and even previous generation hardware.
