Network Earth Position Protocol
NEPP Version 1 is an experimental UDP request/response synchronization
protocol inspired by NTP. The public server uses the unassigned private port
56377/UDP.
Try it
With the reference implementation installed, run:
Example response:
earth_date=2026.431818261511104238
offset_ed=5.499863888505608E-9
round_trip_ed=1.3356719301708866E-8
stratum=1
model_id=1
Version 1 packet
The base packet is 76 octets.
| Offset | Size | Field |
|---|---|---|
| 0 | 1 | Status, Version, and Mode |
| 1 | 1 | Stratum |
| 4 | 4 | Root Delay |
| 8 | 4 | Root Dispersion |
| 16 | 12 | Reference Earth Date |
| 28 | 12 | Origin Earth Date |
| 40 | 12 | Receive Earth Date |
| 52 | 12 | Transmit Earth Date |
| 64 | 8 | Earth Date Rate |
| 72 | 4 | Model ID |
An Earth Date timestamp contains a signed 32-bit Earth Year and an unsigned 64-bit orbital fraction, all in network byte order.
Exchange and correction
Let E1 through E4 be client transmit, server receive, server transmit, and
client receive. Offset and round-trip delay are:
See the complete implementation snapshot, Version 1 implementation snapshot.
The draft archive also provides downloadable sources.
Security
Version 1 is unauthenticated and is vulnerable to spoofing, replay, delay manipulation, false stratum, and denial of service. Origin validation correlates a response but does not authenticate its sender. Trusted uses require an authenticated transport or a future authentication extension.