This configuration command features an IPv6 Neighbor Discovery (ND) option (called Boot File URL (BFURL) option)

Enabling “Proxy ARP/ND for Single Aggregation (AG) VTEP Campus Deployments without EVPN” allows an aggregation VTEP to proxy reply to a VXLAN-encapsulated ARP request/NS when the ARP/NS target host is remote and the ARP/ND binding is already learned by the AG VTEP.

ARP and IPv6 Neighbor Discovery use a neighbor cache to store neighbor address resolutions. The capacity of the neighbor cache is determined by the resources and capabilities of the device platform. The neighbor cache capacity feature adds a means to specify a per-interface capacity for the neighbor cache. A neighboring device, through misconfiguration or maliciousness, can unfairly use a large number of address resolutions. This feature can help to mitigate this over-utilization.

ARP and IPv6 Neighbor Discovery use a neighbor cache to store neighbor address resolutions. The cache maintains the resolutions for an interval of time after which a refresh process begins.  During the refresh process, a number of ARP requests or IPv6 ND Neighbor Solicitations are sent to the neighbor until the neighbor either responds with an ARP reply or IPv6 ND Neighbor Advertisement.

RFC4191 describes an optional extension to Router Advertisement messages for communicating default router

Nd RA RFC4191