BGP-4 Aggregator AS list. This octet string contains
Autonomous System numbers. If an AS appears in this
list, this filter applies to BGP advertisements that contain
the AS number in their AGGREGATOR path attribute.
If non-null, The octet string contains one or more 2-octet
AS numbers. If null, this filter applies to BGP
advertisements with any AS number in the AGGREGATOR
path attribute.