[ntp:questions] root_distance function in ntp_proto.c differs from RFC5905 and NTP 4.2.4p6

blji ubalaji83 at gmail.com
Mon Dec 12 13:26:29 UTC 2011


Hello all,

Currently I have NTP version 4 code from NTP 4.2.4p6(Downloaded from
http://www.eecis.udel.edu/~ntp/ntp_spool/ntp4/ntp-4.2/  File name is :
ntp-4.2.4p6.tar.gz). Now root_distance function in ntp_proto.c is
mentioned as root_dist() in RFC 5905 which is a reference for Network
Time Protocol Version 4: Protocol and Algorithms Specification.

Also following are the differences with root_distance function:
RFC 5905:
return (max(MINDISP, p->rootdelay + p->delay) / 2 +
            p->rootdisp + p->disp + PHI * (c.t - p->t) + p->jitter);

code in NTP 4.2.4p6:
 if (peer->stratum >= sys_orphan)
     dist = 0;
 else
     dist = peer->rootdelay;

 dist += max(sys_mindisp, dist + peer->delay) / 2 +
     peer->rootdispersion + peer->disp + clock_phi *
     (current_time - peer->update) + peer->jitter;
 return (dist);


Kindly let me know to which RFC does the version NTP 4.2.4p6 refers
to.


Thanks a lot.



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