Requested revision
Standard: | IEEE802.1AS-2020 | Clause: | 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 Venkatesan | Email: | ganesh.venkatesan@intel.com |
Affiliation: | Intel Corporation | ||
Submitted: | 2021-05-03 |