Hi Sabine,
please see inline.
On 14.08.2018 19:03, Randriamasy, Sabine (Nokia - FR/Paris-Saclay) wrote:
Hello Mirja,
Thank you so much for your thorough review and suggestions. The authors will
discuss open points such as those relating with metrics and your they will be
integrated in a next version.
Best regards,
Sabine and co-authors
-----Original Message-----
From: Mirja Kuehlewind (IETF) [mailto:[email protected]]
Sent: Monday, August 06, 2018 4:12 PM
To: [email protected]
Cc: [email protected]
Subject: AD review of draft-ietf-alto-cost-calendar-07
Hi all,
I reviewed this draft and there are a few minor fixes that we need before we
can start IETF last call:
1) Please remove the following sentence, or refer to the respective sections
instead:
„IANA considerations and security considerations will be completed in
further versions."
[[SR]] [[SR]] OK, will do and will remove previous sentence on section 5 that
is no longer applicable.
2) Please fix everywhere in the doc:
"Content-Length: TODO“
[[SR]] the value "TODO" was left on purpose, in case we would be asked to
change the names of the metrics. The plan was to fill them up when all the example
metrics will be approved by the reviewers.
Which reviewers? I think the should be filled before we go to IETF last
call, so please do it now.
3) Also please make all occurrences of RFC7285 an actually reference
("[RFC7285]" instead of only „RFC7285“).
[[SR]] OK, will do
4) Then I also have a question about this example in Sec 4.1.2:
"For example: if the "calendar-start-time" member has value "Mon, 30
Jun 2014 at 00:00:00 GMT" and if the value of member "repeated" is
equal to 4, it means that the calendar values are the same values on
Monday, Tuesday, Wednesday and Thursday. The ALTO Client thus may
use the same calendar for the next 4 duration periods following
"calendar-start-time“.“
I think this example only makes sense if also the duration period based on
"time-interval-size“ and "number-of-intervals“ with „1 hour“ and „24“
respectively is given, right? Can you please add this here.
[[SR]] Would the following re-phrasing be fine?
"For example: suppose the "calendar-start-time" member has value "Mon, 30 Jun 2014 at 00:00:00 GMT", the
"time-interval-size" member has value "1 hour", the "number-of-intervals" member has value "24" and the value of
member "repeated" is equal to 4. This means that the calendar values are the same on Monday, Tuesday, Wednesday and Thursday on a period of 24
hours starting at 00:00:00 GMT.
The ALTO Client thus may use the same calendar for the next 4 days starting at
"calendar-start-time" and will only need to request a new one for Friday July 4th at
00:00:00 GMT."
Yes, please.
And one minor (technical) comment/question that I would like to discuss before
we go into IETF last call:
Why is "time-interval-size“ combining the value and unit in one element, instead of e.g.
using "time-interval-unit“ and "time-interval-value“? Would that not make the
implementation of the parsing much simpler?
[[SR]] Parsing 2 separate fields would avoid ambiguities indeed, the idea with this proposed
format was to spare one member to convey in the responses. We took inspiration from the
encoding format of constraints by an ALTO Client in 11.3.2.3 of RFC 7285 that follows a
similar pattern, e.g. "le 15". Would it help if we rephrase the format specification
of the "time-interval-size“ value in section 3.1 to avoid parsing errors ?
I think the approach is fine. I was just wondering why it was chosen.
And finally, you use the cost type names "num-routingcost", "num-latency", "num-pathbandwidth" and
"string-quality-status“ as well as metrics "routingcost", "latency" and "bandwidthscore" in the examples and say
that "The cost types in this example are either specified in the base ALTO
protocol or may be specified in other drafts see
[draft-ietf-alto-performance-metrics] or defined in this draft for
illustrative purposes.“
However, non of these metrics are actually defined in
[draft-ietf-alto-performance-metrics], nor are they „defined“ in this doc.
Would it maybe make sense to actually use cost types and metrics from
[draft-ietf-alto-performance-metrics] in these examples (or remove the
reference and provide some kind of definition)?
[[SR]] We propose to revise the related parts in section 3.3 as follows:
- only reference [draft-ietf-alto-performance-metrics] in section 2.2.1 that
explains how Calendars support all kinds of metrics and modes and remove it
from section 3.3,
- keep the "routingcost" metric,
- define example illustrative costs and metrics in section 3.3, that have names such as "num-owdelay",
"num-throughput", "string-service-status". If we are asked to replace them by cost types with nonsensical
metric names such as "shoesize" or "cattle-head-count", we will do so.
Yes, please define the metric accordingly. I'm okay to have metric that
actually make some sense. Just make sure that these metric are
understood as example metrics only and should not be used. Or would it
make more sense to "just" use some metrics from
[draft-ietf-alto-performance-metrics]?
Mirja
Given I reviewed the whole doc, also a couple of editorial comments/proposals
below (however, I fully leave it to the authors' judgement to apply these or
not).
Thanks!
Mirja
[[SR]] Thanks a lot for your guidance and suggestions
Sabine
————————————————
Other editorial comments:
1) The abstract is quite long. I think if it could be formulated more crisp, it
would be easier to read, e.g. see the text in the shepherd write-up
"This document is an extension to the base ALTO protocol (RFC 7785). It
extends the ALTO cost information service such that applications decide not only
'where' to connect, but also 'when'. This is useful for applications that need to
perform bulk data transfer and would like to schedule these transfers during an
off-peak hour, for example.“
[[SR]] OK will do
2) I know that IRD is on the known abbreviation list, maybe still spell it out
at first occurrence for the ease of the reader…?
[[SR]] OK will do
3) As the alto base spec is already published for a while, maybe:
OLD
"IETF is currently standardizing the ALTO protocol which aims at
providing guidance to overlay applications…“ NEW "The ALTO protocol
provides guidance to overlay applications…“
[[SR]] OK will do
4) Maybe:
OLD
“...for example by deferring backup to night
during traffic trough.“
NEW
"for example by deferring backups or other background traffic to off-peak
hours.“
[[SR]] OK will do
5) To be inline with previously used wording, maybe OLD „...we expect to further
gain on storage and on the wire data exchange…“ NEW "we expect to further
save network and storage resources…“
[[SR]] OK will do
6) sec 2.2 "The protocol extension placeholders for an ALTO Calendar are: the
IRD, the ALTO requests and responses for Cost calendars.“ Not sure I fully
understand the word „placeholder“ here, maybe:
„To realize an ALTO Calendar, this document extends the
IRD, the ALTO requests and responses for Cost calendars.“ ?
[[SR]] OK will do
Also further
"Extensions are designed to be light and ensure backwards
compatibility with base protocol ALTO Clients and with other
extensions. It uses section 8.3.7...“ What is „it“ here?
Maybe:
„This extension is designed to be light and ensure backwards
compatibility with base protocol ALTO Clients and with other
extensions. As recommended, it relies on section 8.3.7…“ ?
[[SR]] OK will do
7) Sec 4.1.1:
"A Calendar-aware ALTO client supporting single cost type values, as
specified in RFC7285, MUST provide an array of 1 element:
"calendared" : [true];“ This could be stated more
clearly e.g.
"A Calendar-aware ALTO client only supporting single cost type values, as
specified in RFC7285, that aims to request a Calendar MUST provide
an array of 1 element:
"calendared" : [true];“
[[SR]] OK will do
8) 4.2.2
"If the value of member "calendared" is equal to 'false' for a given
requested Cost Type, the ALTO Server must return, for these Cost
Types, a single cost value as specified in RFC 7285.“ Probably use
normative MUST here instead.
[[SR]] OK will do
9) Probably RFC5246 does not need to be a normative reference for this doc (as
it is already normative for RFC7285).
[[SR]] OK, will move it to Informative
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