This ZeroBasedCounter32 counts how many times a CDP neighbor's complete set of advertised information was purged switch-wide because its information-timeliness interval expired without a refresh, incrementing once per neighbor even though multiple related table entries are invalidated together. An admin watches it to detect neighbors that have silently stopped sending CDP updates, whether from a crash, misconfiguration, or a dead link, without relying on interface link-state alone. A rising ageout count with no corresponding rise in zxr10CdpStatsRemInserts points to neighbors going stale rather than the topology simply growing.