ES ESI-1 is configured with all the required parameters, as described in All-active multi-homing service model. When ethernet-segment no shutdown is executed, PE1 and PE2 advertise an ES route for ESI-1. They both include the route-target auto-derived from the MAC portion of the configured ESI. If the route-target address family is configured in the network, this allows the RR to keep the dissemination of the ES routes under control.
In addition to the ES route, PE1 and PE2 advertise AD per-ESI routes and AD per-EVI routes:
AD per-ESI routes announces the ES capabilities, including the mode (single-active or all-active) and the ESI label for split horizon.
AD per-EVI routes are advertised so that PE3 knows what services (EVIs) are associated with the ESI. These routes are used by PE3 for its aliasing and backup procedures.