In a Cisco ACI multisite setup, symmetric ingress and egress traffic flows for stretched bridge domains are essential for consistent network behavior. Configuring host route advertisement on the bridge domains allows each site to advertise its local endpoints' routes. This ensures that return traffic is directed to the originating site, maintaining symmetric traffic flow. When host routes are advertised from the bridge domains, it allows for more granular control of traffic, ensuring that packets take the same path into and out of the network, which is particularly important in stretched scenarios whereapplications might span multiple sites. References := ( Implementing Cisco Application Centric Infrastructure Official Cert Guide )