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Requested revision
Standard:IEEE802.1AS-2020Clause:12.7
Clause title:Format of VendorSpecific information element
Rationale for revision
Some implementations require an alternate set of information in order to correlate the time value in the preciseOriginTimestamp field of the FollowUpInformation to the timestamp information (t1, t4).
Proposed text
replace the text in Clause 12-7 describing the Type field to the following: The Type field, illustrated in Figure 12-8, identifies this use of the OUI or CID within the VendorSpecific information element. Table 12-4 lists values for the Type field. When the Type field is set to 0, this mechanism shall be used to carry end-to-end link-independent timing information from the master port to the associated slave port, including preciseOriginTimestamp, rateRatio, correctionField, and other fields of the Follow-Up message, as described in 12.5.1.4. For consistency, all of these fields are packed into the FollowUpInformation field using exactly the same format as used for full-duplex point-to-point links. In other words, the master state machine communicates an entire Follow_Up message [i.e., including all the fields of the common header (see 11.4.2 and 10.6.2), the preciseOriginTimestamp, and all the fields of the Follow_Up information TLV (see 11.4.4)] using this mechanism. When the Type field is set to 1, this mechanism shall be used to carry end-to-end link-independent timing information from the master port to the associated slave port, including preciseOriginTimestamp, rateRatio, preciseOriginTimestamp corresponding to timestamp t4, and other fields of the Follow-Up message, as described in 12.5.1.4. For consistency, all of these fields are packed into the FollowUpInformation field using exactly the same format as used for full-duplex point-to-point links. In other words, the master state machine communicates an entire Follow_Up message [i.e., including all the fields of the common header (see 11.4.2 and 10.6.2) with the exception of the correctionField, the preciseOriginTimestamp, and all the fields of the Follow_Up information TLV (see 11.4.4)] using this mechanism.
Impact on existing networks
There should be no impact on existing networks/implementations as type-1 is currently a reserved value (and implementations are expected to ignore this type).
Originator
Name:Ganesh VenkatesanEmail:ganesh.venkatesan@intel.com
Affiliation:Intel Corporation
Submitted:2021-05-03