On Sep 19, 2008, at 7:47 AM, Kukosa, Tomas wrote:
SNTP does not have own protocol format, it uses the same packets as
NTP, i.e. Wiresahrk does not discern SNTP and NTP as there is
anything like SNTP packet format, just NTP.
As I know difference bteween NTP and SNTP is just in complexicity of
communication among synchronized entities and in complexicity of
handling of all those packets.
Yes, as you said, SNTP isn't a separate protocol from NTP; to quote,
for example, RFC 1769:
This memorandum describes the Simple Network Time Protocol (SNTP),
which is an adaptation of the Network Time Protocol (NTP) used to
synchronize computer clocks in the Internet. SNTP can be used when the
ultimate performance of the full NTP implementation described in
RFC-1305 is not needed or justified. It can operate in both unicast
modes (point to point) and broadcast modes (point to multipoint). It
can also operate in IP multicast mode where this service is available.
SNTP involves no change to the current or previous NTP specification
versions or known implementations, but rather a clarification of
certain design features of NTP which allow operation in a simple,
stateless remote-procedure call (RPC) mode with accuracy and
reliability expectations similar to the UDP/TIME protocol described in
RFC-868.
and RFC 4330:
This memorandum describes the Simple Network Time Protocol Version 4
(SNTPv4), which is a subset of the Network Time Protocol (NTP) used to
synchronize computer clocks in the Internet. SNTPv4 can be used when
the ultimate performance of a full NTP implementation based on RFC
1305 is neither needed nor justified. When operating with current and
previous NTP and SNTP versions, SNTPv4 requires no changes to the
specifications or known implementations, but rather clarifies certain
design features that allow operation in a simple, stateless remote-
procedure call (RPC) mode with accuracy and reliability expectations
similar to the UDP/TIME protocol described in RFC 868.
so, as you indicated, Wireshark "supports" SNTP because it dissects
NTP packets and SNTP packets are just NTP packets.
