16. IANA Considerations
This document involves several IANA registry and assignment matters for the Network Time Protocol.
16.1. Port Assignment
UDP/TCP Port 123 was previously assigned by IANA for this protocol and continues to be used.
16.2. Multicast Address Assignment
IANA has assigned:
- IPv4 multicast group address: 224.0.1.1
- IPv6 multicast address: ending with :101
These addresses are used for NTP broadcast and multicast modes.
16.3. Extension Field Types Registry
This document introduces NTP extension fields allowing for future protocol extensions. IANA has established and maintains a registry for Extension Field Types, identified by the Field Type sub-field within the extension field.
Registration Policy: New Extension Field Types are defined by IETF Review, following policies outlined in RFC 5226.
Initial State: Registry populated with no initial entries, to be extended as future needs arise.
16.4. Reference Identifier Codes Registry
IANA has created a registry for NTP Reference Identifier codes. This includes current codes defined in Section 7.3.
Registration Policy: First-Come-First-Serve (FCFS) basis.
Registry Format:
| ID | Clock Source |
|---|---|
| GOES | Geosynchronous Orbit Environment Satellite |
| GPS | Global Position System |
| GAL | Galileo Positioning System |
| PPS | Generic pulse-per-second |
| IRIG | Inter-Range Instrumentation Group |
| WWVB | LF Radio WWVB Fort Collins, CO 60 kHz |
| DCF | LF Radio DCF77 Mainflingen, DE 77.5 kHz |
| HBG | LF Radio HBG Prangins, HB 75 kHz |
| MSF | LF Radio MSF Anthorn, UK 60 kHz |
| ... | ... |
16.5. Kiss-o'-Death Codes Registry
IANA has created a registry for NTP Kiss-o'-Death codes. These codes are returned in the Reference Identifier field to indicate various error conditions. This includes current codes defined in Section 7.4.
Registration Policy: First-Come-First-Serve (FCFS) basis.
Registry Format:
| Code | Meaning |
|---|---|
| ACST | The association belongs to a unicast server |
| AUTH | Server authentication failed |
| AUTO | Autokey sequence failed |
| BCST | The association belongs to a broadcast server |
| CRYP | Cryptographic authentication or identification failed |
| DENY | Access denied by remote server |
| DROP | Lost peer in symmetric mode |
| RSTR | Access denied due to local policy |
| INIT | The association has not yet synchronized |
| MCST | The association belongs to a manycast server |
| NKEY | No key found |
| RATE | Rate exceeded |
| RMOT | Alteration of association from a remote host |
| STEP | A step change in system time has occurred |
| ... | ... |
16.6. Experimental Code Reservation
For both Reference Identifiers and Kiss-o'-Death codes, IANA is requested to never assign a code beginning with the character "X", as this prefix is reserved for experimentation and development purposes.
This reservation allows implementers to test new clock sources and error conditions without risk of conflict with officially assigned codes.