The router determines the router ID for each peer that advertised a path to the route destination. A lower router ID value is preferred over a higher router ID value. 10. The router determines the peer ID for each peer that advertised a path to the router destination. A lower peer ID value is preferred over a higher peer ID value. The peer ID is the IP address of the established BGP peering session.

Bridge priority is to determine which bridge becomes the designated bridge.

BUM Traffic Forwarding
Junos devices that use MPLS encapsulation for EVPNs can only use ingress replication at this time.
Ingress replication means, to flood traffic to remote PE routers, the traffic has to be replicated, once for each remote PE router.
The EVPN label for this BUM traffic is learned per PE router from the route type 3, inclusive multicast Ethernet tag route.
This table shows the format of the inclusive multicast Ethernet tag route.
All-Active Redundancy (4)
This diagram shows the format of the type 1 route, A-D route per ES. The split horizon label is advertised as part of an extended community attached to the type 1 route. The split horizon label is also called the ESI label. The extended community also indicates what type of redundancy mode is used for this given ESI: single-active represented by binary 1 or active-active represented by binary 0.