|Standard:||IEEE Std 802.1AS-2020||Clause:||10.6.4.2.2; 10.6.4.1|
|Clause title:||Message interval request TLV or gPTP capable TLV; General Signaling message specifications|
Rationale for revision
Subclause 10.6.4.2.2 does not mention the gPTP capable message interval request TLV. In case the "or" in table 10-13 is meant in an exclusive way, it would mean that none of the TLVs can be sent in the same message with another TLV. It should be made clear if the gPTP capable message interval request TLV can be sent in one message with one of the other TLVs. Was it intended that the gPTP capable TLV is always sent as a separate signaling message? In addition the length of the TLVs shown in table 10-13 is inconsistent with the length definition of the gPTP capable message interval request TLV, it is only 14 octets long.
Change the text to: 10.6.4.2.2 Number of TLVs carried in one Signaling message The Signaling message carries either one or both interval request TLVs, defined in 10.6.4.3 and 10.6.4.5, or the gPTP capable TLV, defined in 10.6.4.4, but not both. This means that the gPTP capable TLV is always sent in a separate Signaling message. Change table 10-13 as follows: Change the following text: "message interval request TLV, gPTP capable TLV, or gPTP capable message interval request TLV" to either: "message interval request TLV and/or gPTP capable message interval request TLV, or gPTP capable TLV" or: "one or more TLVs" Change the number of octets of the TLVs to N.
Impact on existing networks
The proposed revision text requires devices to support signaling messages carrying both interval request TLVs. If there are already implementations that only support at most one of the TLVs in one Signaling message they would ignore the second message. In case this is a concern, it should be required to send all TLVs in separate Signaling messages.