This is an extension to BGP EVPN VPNs that allow us to use iBGP as the PE-CE protocol. This feature also provides a way to isolate the customer’s network BGP attributes from the SP backbone’s attributes, by saving them into a special attribute called ATTR_SET, code 128. This separation introduces a “route server” model that allows the customer’s BGP path attributes to be stored in the SP backbone along with the VPN-IPv4/v6 paths.