This read-only TimeFilter value, as defined in RFC 2021, marks a CDP neighbor table entry for time-based filtered retrieval, allowing a manager to fetch only entries that have changed since a given time. An administrator or monitoring tool uses this in conjunction with TimeFilter-based GetNext operations to efficiently retrieve incremental neighbor table updates rather than the whole table each poll. For example, a network discovery tool remembers the highest TimeFilter value from its last poll and requests only neighbor entries updated since then to reduce polling overhead.