AA subscriber per-subscriber policers can provide per-SAP policing for the parent SAP, with transit AA subscribers each supporting distinct per-subscriber policers within the parent (packets are only processed once against one AA subscriber, the parent or the transit subscriber). Packets matching transit AA subscribers and policers are not included in a parent policer.
There is no policer hierarchy unless system wide policers are referred to by both the parent AA subscriber and transit AA subscriber. When the remote-site configuration is not used, system policers can be used to police all traffic for a site containing transits, subject to constraints on system policer scale.
When the remote-AA subscriber config is used, the parent owns all packets for stats and policing, so any transit subscriber configuration within the parent does not affect the stats or policers. AA policers are supported on a transit subscriber basis, across all (multiple) IP prefixes per sub.