from RIPv6' gateway list. Only applicable for RIPv6 sourced
routes and if RIPv6 is included as a route source. This octet
string contains the addresses of one or more routers that could
send RIPv6 updates to this router. If a router address is
included in this list, this filter applies to RIPv6
advertisements from that router.
If non-null, The octet string contains one or more 2-tuples
of this form:
first 4 octets: interface index
next 16 octets: router address (::0 means any address)
If null, this filter applies to RIPv6 updates from any router.