Layer2 Flooding
Cisco SD-Access fabric provides many optimizations to improve unicast traffic flow, and to reduce the unnecessary flooding of data such as broadcasts. But, for some traffic and applications, it may be desirable to enable broadcast forwarding within the fabric.
By default, this is disabled in the Cisco SD-Access architecture. If broadcast, Link local multicast and Arp flooding is required, it must be specifically enabled on a per-subnet basis using Layer 2 flooding feature.
Layer 2 flooding can be used to forward broadcasts for certain traffic and application types which may require leveraging of Layer 2 connectivity, such as silent hosts, card readers, door locks, etc.