Internet Engineering Task Force (IETF) A. Morton Request for Comments: 7718 AT&T Labs Updates: 4656 December 2015 Category: Standards Track ISSN: 2070-1721
Registries for the One-Way Active Measurement Protocol (OWAMP)
This memo describes the registries for OWAMP -- the One-Way Active Measurement Protocol. The registries allow assignment of Mode bit positions and OWAMP Command numbers. Per this memo, IANA has established the registries for new features, called the OWAMP-Modes registry and the OWAMP Control Command Number registry. This memo updates RFC 4656.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741.
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The One-Way Active Measurement Protocol (OWAMP) [RFC4656] was prepared to support measurements of metrics specified by the IP Performance Metrics (IPPM) working group in the IETF. The Two-Way Active Measurement Protocol (TWAMP) [RFC5357] is an extension of OWAMP. The TWAMP specification gathered wide review as it approached completion, and the by-products were several recommendations for new features in TWAMP. As a result, a registry of new features was established for TWAMP. However, there were no new features proposed for OWAMP until recently [RFC7717].
This memo establishes the needed registries for OWAMP and updates [RFC4656].
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].
The purpose and scope of this memo is to describe and request the establishment of registries for future OWAMP [RFC4656] extensions. IANA already administers the "Two-way Active Measurement Protocol (TWAMP) Parameters", and this request follows a similar form (with one exception identified below).
This memo also provides the initial contents for the OWAMP registries.
3. IANA Considerations for OWAMP-Control Registries
The OWAMP-Control protocol coordinates the measurement capability. All OWAMP-Control messages follow specifications defined in Section 3 of [RFC4656].
Because the "OWAMP-Control Command Numbers" registry can contain only 256 values, and because OWAMP is an IETF protocol, these registries MUST be updated only by "IETF Review" as specified in [RFC5226] (an RFC that documents registry use and is approved by the IESG).
OWAMP-Modes are specified in OWAMP Server Greeting messages and Set- up Response messages consistent with Section 3.1 of [RFC4656]. Modes are currently indicated by setting single bits in the 32-bit Modes field. However, more complex encoding may be used in the future.
Because the "OWAMP-Modes" are based on only 32 bit positions with each position conveying a unique feature, and because OWAMP is an IETF protocol, these registries MUST be updated only by "IETF Review" as specified in [RFC5226] (an RFC that documents registry use and is approved by the IESG). IANA SHOULD allocate monotonically increasing bit positions when requested.
OWAMP-Control connection establishment follows the procedure defined in Section 3.1 of [RFC4656].
Morton Standards Track [Page 4]
RFC 7718 OWAMP Registries December 2015
In the OWAMP-Modes registry, assignments are straightforward on the basis of bit positions, and there are no references to values -- this is a difference from the comparable TWAMP registry (and a topic for improvement in the TWAMP-Modes registry that is reconciled in [RFC7717]).
An extension of the OWAMP-Modes is proposed in [RFC7717]. With this extension, the complete set of OWAMP Mode bit positions are as follows (including one reserved bit position):
In the original OWAMP Modes field, setting bit position 0, 1, or 2 indicated the security mode of the Control protocol, and the Test protocol inherited the same mode (see Section 4 of [RFC4656]).
The value of the Modes field sent by the Server in the Server- Greeting message is the bit-wise OR of the modes (bit positions) that it is willing to support during this session. Thus, the five least significant bits of the 32-bit Modes field are used. When no other features are activated, the 27 most significant bits MUST be zero. A Control-Client conforming to [RFC4656] MAY ignore the values in the 29 most significant bits of the Modes field, or it MAY support features that are communicated in other bit positions, such as the IKEv2-derived Shared Secret Key extension [RFC7717].
OWAMP and TWAMP registries for Modes may grow to contain different features and functions due to the inherent differences in one-way and two-way measurement configurations and the metrics they measure. No attempt will be made to coordinate them unnecessarily, except for the Reserved bit position 3 above. This is available for assignment if a mixed security mode similar to [RFC5618] is defined for OWAMP; it would allow alignment with the comparable TWAMP feature.
The author would like to thank Kostas Pentikousis, Nalini Elkins, Mike Ackermann, and Greg Mirsky for insightful reviews and comments. We thought Spencer Dawkins caught the last of the small errors in his AD review, but Nevil Brownlee found a few more during OPS-DIR review. Roni Even found our use of "IETF Consensus" was out of date with [RFC5226]. Michelle Cotton helped to clarify the IANA considerations.
Al Morton AT&T Labs 200 Laurel Avenue South Middletown,, NJ 07748 United States