Vxlan Bgp Evpn Control Plane - Cisco Nexus 7000 Series Configuration Manual

VXLAN BGP EVPN Control Plane

• Global unicast table
VXLAN BGP EVPN Control Plane
The EVPN overlay specifies adaptations to the BGP MPLS-based EVPN solution to enable it to be applied
as a network virtualization overlay with VXLAN encapsulation where:
• PE node role described in BGP MPLS EVPN is equivalent to VTEP/network virtualization edge (NVE)
• VTEP information is distributed via BGP.
• VTEPs use control plane learning/distribution via BGP for remote MAC addresses instead of data plane
• Broadcast, unknown unicast and multicast (BUM) data traffic is sent using a shared multicast tree.
• BGP route reflector (RR) is used to reduce the full mesh of BGP sessions among VTEPs to a single
• Route filtering and constrained route distribution are used to ensure that the control plane traffic for a
• Host (MAC) mobility mechanism to ensure that all the VTEPs in the overlay instance know the specific
• Virtual network identifiers (VNIs) are globally unique within the overlay.
The EVPN overlay solution for VXLAN can also be adapted to enable it to be applied as a network virtualization
overlay with VXLAN for Layer 3 traffic segmentation. The adaptations for Layer 3 VXLAN are similar to
L2 VXLAN except the following:
• VTEPs use control plane learning/distribution via BGP of IP addresses (instead of MAC addresses)
• The virtual routing and forwarding instance is mapped to the VNI
• The inner destination MAC address in the VXLAN header does not belong to the host but to the receiving
Cisco Nexus 7000 Series NX-OS VXLAN Configuration Guide
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This situation can occur for instance at the data center edge where the overlay network feeds into an
MPLS VPN. In this case, the identifier may be dynamically allocated by the advertising device.
It is important to support both cases, and in doing so, ensure that the scope of the identifier be clear and
the values not conflict with each other.
It should be noted that deployment scenarios for these virtual network overlays are not constrained to
the examples used above to categorize the options. For example, a virtual network overlay may extend
across multiple data centers.
The overlay encapsulation can also be used to support forwarding for routes in the global or default
routing table. A VNI value can be allocated for the purpose as per the options mentioned above.
device.
learning.
BGP session between a VTEP and the RR.
given overlay is only distributed to the VTEPs that are in that overlay instance.
VTEP associated with the MAC.
VTEP that does the routing of the VXLAN payload. This MAC address is distributed via BGP attribute
along with EVPN routes.
Overview