Not applicable for first phase of Integrated IS_IS
from EGP' Gateway list. Only applicable for EGP sourced
routes and if EGP is included as a route source. This octet
string contains the IP address of one or more EGP gateways.
If an EGP gateway is included in this list, this filter applies
to EGP advertisements that use this gateway as the next hop.
If non-null, The octet string contains one or more 4-octet
IP addresses. If null, this filter applies to EGP
advertisements with any gateway address.