[ntp:questions] NTP vs chrony comparison (Was: oscillations in ntp clock synchronization)

David L. Mills mills at udel.edu
Thu Jan 24 21:47:13 UTC 2008


Reprinted without permission from the draft spec:

14.  Simple Network Time Protocol (SNTP)

    Primary servers and clients complying with a subset of NTP, called
    the Simple Network Time Protocol (SNTPv4) [2], do not need to
    implement the mitigation algorithms described in Section 9 and
    following sections.  SNTP is intended for primary servers equipped
    with a single reference clock, as well as for clients with a single
    upstream server and no dependent clients.  The fully developed NTPv4
    implementation is intended for secondary servers with multiple
    upstream servers and multiple downstream servers or clients.  Other
    than these considerations, NTP and SNTP servers and clients are
    completely interoperable and can be intermixed in NTP subnets.

    An SNTP primary server implementing the on-wire protocol described in
    Section 8 has no upstream servers except a single reference clock.
    In principle, it is indistinguishable from an NTP primary server that
    has the mitigation algorithms and therefore capable of mitigating
    between multiple reference clocks.

    Upon receiving a client request, an SNTP primary server constructs
    and sends the reply packet as described in Figure 34.  Note that the
    dispersion field in the packet header must be updated as described in
    Section 5.


Danny Mayer wrote:


More information about the questions mailing list