|Clause title:||correctionField (Integer64)|
Rationale for revision
Subclause 126.96.36.199 of IEEE 1588 - 2008 indicates that the correctionField of the Sync message shall be zero in the case of a two-step clock. In addition, Table 21 of 1588 says that the correctionField of Announce and Signaling messages (and management messages, but these are not used in 802.1AS) is zero. Finally, subclause 11.4.3. of IEEE 1588-2008 indicates that the correction field of the Pdelay_Req message is set to zero by the Pdelay requestor. It was intended that the correctionField of Sync, Announce, Signaling, and Pdelay_Req in 802.1AS should be zero, since the correctionField of these messages is not used (in the case of Sync, it is because the clocks are two-step). However, Table 11-5 of 802.1AS does not indicate that the correctionField is zero for these messageTypes. Note that this maintenance request is related to another maintenance request that indicates that Table 11-5 incorrectly says that the correctionField for Pdelay_Req contains corrections for fractional ns (and indicates that Pdelay_Req should be removed from that row). Note that this change was proposed in a comment during the sponsor ballot recirculation for P802.1AS-Cor-1 (comment #7 in the final comment resolution for draft D3.1). The comment was rejected because it was out of scope, but the committee thought it would be desirable to make this fix in P802.1ASbt, and indicated the editor should submit this item for entry in the maintenance database.
Add a row to Table 5 of 802.1AS indicating that the correctionField is zero for Sync, Announce, Signaling, and Pdelay_Req.
Impact on existing networks
This has no impact on existing networks; it simply makes it clear that the correctionField is not used for Sync, Announce, and Pdelay_Req messages, and explicitly indicates the field is set to zero.
|Name:||Geoffrey M. Garner||Email:||firstname.lastname@example.org|
|Affiliation:||Broadcom, Hirschmann, Marvell, Siemens|