The timestamp in the NTP packet is a 32bit integer which represents the number of seconds after 00:00 01/01/1900. This 32bit number will wrap around at 06:28:16 Feb 7 2036. At this point in time, the eCos time will jump back to around 00:00:00 Jan 1 1900 when the next NTP packet is received.
YOU HAVE BEEN WARNED!