in the ESP8266 Example NTP-TZ-DST.ino you find following comment
// OPTIONAL: change SNTP startup delay
// a weak function is already defined and returns 0 (RFC violation)
// it can be redefined:
//uint32_t sntp_startup_delay_MS_rfc_not_less_than_60000 ()
//{
// //info_sntp_startup_delay_MS_rfc_not_less_than_60000_has_been_called = true;
// return 60000; // 60s (or lwIP's original default: (random() % 5000))
//}
Can anyone point me to that RFC where this 60 seconds are defined as mandatory?
I find the 15 seconds of the polling intervall in the "best practices" of RFC4330 https://tools.ietf.org/html/rfc4330#page-21
When the client is first coming up or after reset, randomize the
timeout from one to five minutes. This is to minimize shock when
3000 PCs are rebooted at the same time power is restored after a
blackout.
the RFC4330 is marked as obsolete and replaced by the RFC5905 (as I understand, RFC4330 was incooperated into chapter 14 of RFC5905) where in RFC5905 is the evidence that this boot delay is required in a SNTP implementation?