This Unsigned32 (1-65535) is the number of seconds a receiving LLDP agent should regard the associated remote neighbor information, keyed by MSAP identifier, as valid before it ages out. An admin reads this to understand how long stale LLDP neighbor data will linger before being purged if the neighbor stops advertising. For example, an operator troubleshooting a topology tool showing a disconnected neighbor as still present would check f3LldpV2RemTTL to see how long that stale entry is expected to persist before aging out.