i want to use NTP, not RTP to get time in millisecond. is there any way possible to use it ? thanks
NTP is network time protocol. It is the standard method for getting time via the internet. For this, you need, for example, a WLAN capable module e.g. ESP8266 / ESP32.
What do you mean by RTP in this context ? If you do mean RTP, please include a link to a description which you think is relevant to obtaining time in milliseconds.
If you mean RTC (real time clock) these usually have a time granularity of one second. This means you have to poll them regularly to watch the second roll over and set the MCU clock which then delivers your millisecond accuracy. Some RTC modules deliver a 1Hz clock whcih you can also use to determine the second rollover.