def _get_up_down(self):
return self.__up_down<EOL>
Getter method for up_down, mapped from YANG variable /network_instances/network_instance/protocols/protocol/isis/levels/level/link_state_database/lsp/tlvs/tlv/ipv4_internal_reachability/prefixes/prefixes/state/up_down (boolean)

    YANG Description: The up/down bit. Set if a prefix is advertised from a higher level to
a lower level (e.g., level 2 to level 1), indicating that the prefix
has traveled down the hierarchy. Prefixes that have the up/down bit
set may only be advertised down the hierarchy, i.e., to lower levels.
When a prefix is first injected into IS-IS, the bit is UNSET.