RFC 6374, "Packet Loss and Delay Measurement for MPLS Networks", September 2011Source of RFC: mpls (rtg)
See Also: RFC 6374w/ inline errata
Errata ID: 4000
Publication Format(s) : TEXT
Reported By: Stewart Bryant
Date Reported: 2014-05-27
Verifier Name: Alia Atlas
Date Verified: 2014-05-28
Section 3.5 says:
Upon receipt of a query message including an unrecognized mandatory TLV object, the recipient MUST respond with an Unsupported Mandatory TLV Object error code.
It should say:
In this specification an object that is classed as mandatory is one that the responder MUST either support or respond to indicating that it does not support. Thus upon receipt of a query message including an unrecognized mandatory TLV object, the recipient MUST respond with an Unsupported Mandatory TLV Object error code. Note that the term mandatory does not indicate mandatory to implement or mandatory to send.
In discussion on the MPLS list there was concern about the meaning
of the term "mandatory" in this RFC. The use of the term is
somewhat unusual in an IETF context, but the quoted original
text makes it clear that there is no requirement to implement
mandatory objects, only to respond to the reception of one if
it is not supported.