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Shepherd writeup
draft-ietf-alto-performance-metrics

1. Summary

Jan Seedorf is the document shepherd for draft-ietf-alto-performance-metrics.
Martin Duke is the responsible Area Director.

The ALTO base protocol (RFC7285) defines only a single cost metric, the generic
“routing cost” metric. As new ALTO use cases are being envisioned (e.g. CDN,
5G, data-intensive science applications, flexible inter-domain routing, etc.),
the demand for more concrete cost metrics to be conveyed via the ALTO protocol
arises. This document defines a multitude of such concrete ALTO cost metrics,
such as one-way delay, hop count, residue bandwidth, and several more.

This document is targeted as a Standards Track document (Proposed Standard).
This designation is appropriate as the document contains normative behaviour
and specifies several additions to the IANA "ALTO Cost Metric Registry" that
should be adhered to by the communicating entities in order to realize the
extension.

2. Review and Consensus
The document was introduced originally in 2013 and has been iterated and
presented at IEFT meetings many times. It was adopted as WG item in 2016,
showing the general consensus in the ALTO WG for adding more concrete costs
metrics to the ALTO protocol.

The proposed metrics have been discussed extensively at IETF meetings and on
the mailing list. Since some of these metrics must to be specified in an
unambiguous fashion with clear semantics, external help from IETF experts was
obtained: in 2018 a “Tsvart early review” was performed by Brian Trammell. The
outcome has been discussed on the mailing list and has been addressed in newer
versions of the document. Also, advice from IETF experts from the IPPM WG on
the semantics of the proposed metrics was obtained, discussed, and incorporated
into the document. All of these changes and semantics have been presented to
the ALTO WG multiple times.

In summary, there is clear consensus for draft-ietf-alto-performance-metrics in
the ALTO WG, and it provides very useful cost metric extensions needed for many
of the currently envisioned (future) ALTO use cases. A WGLC has successfully
been passed with no objections, and extensive reviews were provided by various
members of the WG and have all been addressed.

3. Intellectual Property
The shepherd confirms that each author has stated to him that to the best of
his/her (i.e. the author’s) knowledge, all IPR related to this document has
been disclosed.

4. Other Points
Note any downward references (see RFC 3967) and whether they appear in the
DOWNREF Registry
(http://trac.tools.ietf.org/group/iesg/trac/wiki/DownrefRegistry), as these
need to be announced during Last Call.

All normative references are ok (with respect to RFC 3967) as they are all
towards documents with standards-level “Proposed Standards”, “Internet
Standard”, or “BCP”.
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