# RFC Errata

### RFC 5905, "Network Time Protocol Version 4: Protocol and Algorithms Specification", June 2010

Source of RFC: ntp (int)
Errata ID: 5600

**Status: Reported
Type: Technical
Publication Format(s) : TEXT**

Reported By: Takashi Nakamoto

Date Reported: 2019-01-15

Section 10. says:

Let the first stage offset in the sorted list be theta_0; then, for the other stages in any order, the jitter is the RMS average +----- -----+^1/2 | n-1 | | --- | 1 | \ 2 | psi = -------- * | / (theta_0-theta_j) | (n-1) | --- | | j=1 | +----- -----+

It should say:

Let the first stage offset in the sorted list be theta_0; then, for the other stages in any order, the jitter is the RMS average +----- -----+^1/2 | n-1 | | --- | | 1 \ 2 | psi = | -------- * / (theta_0-theta_j) | | (n-1) --- | | j=1 | +----- -----+

Notes:

The formula to calculate jitter "psi" in section "10. Clock Filter Algorithm" is incorrect, and also inconsistent with the formulate to calculate "psi_s" in section "11.2.2. Cluster Algorithm".

"psi" is defined as RMS average, so the term 1/(n-1) should be within [ ]^1/2 block.