Description: Indicates the last time when the upstream port of the monitored groups is down. The value format of this leaf is an 8-byte hexadecimal number. Among the eight bytes, the first and second bytes indicates the year, the third byte indicates the month, the fourth byte indicates the day, the fifth byte indicates the hour, the sixth byte indicates the minute, the seventh byte indicates 1/10 second and is fixedly filled with 0, and the eighth, ninth, and tenth bytes indicate the time zone. For example, if the time is 2010-2-8, 10:11:38 in GMT+ 8, the value is 0x07 0xDA 0x02 0x08 0x0A 0x0B 0x26 0x00 0x2B 0x08 0x00. Because the time range that can be identified by the device is from 1970-01-01 00:00 to 2099-12-31 23:59, the time set for this leaf must within this time range.