Mobatime DTS 4801.masterclock, Instruction Manual

Page: 80 / 120

© MOBATIME 80 / 120 800652.11
8.4 Time server

NTP v4 (compatible with v3) as per RFC 1305 (Port 123)
NTP Authentication with MD5 Key / Autokey

SNTP (UDP), RFC2030 (Port 123)

TIME (TCP/UDP), RFC 868 (Port 37)

DAYTIME (TCP/UDP), RFC 867 (Port 13)
8.5 Time accuracy, time-keeping
See Appendix I Technical data.
8.6 Leap second
Manual mode
Notification of the leap second is always issued 1 hour before the period of time set via
DCF and NTP*.
*Notification is only transmitted via NTP, if the local source or a DCF source is switched
on. If only a NTP source/s is configured, the state of the source will be passed on.
Automatic mode
In automatic mode, the source is checked for 1 hour before the time of the possible
leap second (DCF or NTP) for any possible notification. If notification is recognized, it
will be passed on via NTP and DCF output and the leap second added.
8.7 NTP Authentication
NTP provides two variants for authentication in version 4:

NTP symmetric keys (i.e. symmetric keys)

NTP autokeys
NTP authentication assures a correct time source and prevents manipulation of NTP
information. NTP data itself is, however, not coded.
8.7.1 NTP symmetric keys
A 32-bit key ID and a cryptographic 64/128-bit hash value of the packet is attached to
each NTP IP packet.
The following algorithms are used for this purpose:

Data Encryption Standard (DES)
(partly restricted in North America and no longer integrated into new NTP variants
(>V4.2))

Message Digest (MD5)
The DTS 480x only supports the MD5 procedure.