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 <2b076a38f84c0d0-0000f.Richmail.00002072355849815360@chinamobile.com>
From: Jacqui <jacqui.ietf@gmail.com>
Date: Tue, 23 Jun 2026 12:38:49 +1000
Message-ID: 
 <CAHfxHDrH6_opBRfeZAp5NRAA74TLcekhj_BH3rqyZdaE9-nrCg@mail.gmail.com>
To: Yao Kehan <yaokehan@chinamobile.com>
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Hello,


Thank you for the positive engagement with the feedback and prompt updates
to the draft. I have reviewed the latest version
(draft-ietf-cats-metric-definition-10) and am happy to see how it has
developed.


The security considerations section now provides a far better picture of
the overall security aspects. The opening paragraph does a great job of
conveying the importance of the security considerations and sets up the
remainder of the section well. The format used to cover the individual
components (integrity, authenticity, controllability, freshness, and
confidentiality) is clear and concise, helping readers step through the
different aspects. I really appreciate the work that was put into building
this out.


As for the suggestions on the CATS Metric Fields, removing the =E2=80=9Copt=
ional=E2=80=9D
wording from *Source* and adding =E2=80=9CLevel 0=E2=80=9D as an option for=
 *Level* has
cleared up any confusion.


I look forward to seeing how this document continues to develop as it
progresses through the RFC process.


Thanks

Jacqui

On Mon, Jun 22, 2026 at 8:54=E2=80=AFPM Yao Kehan <yaokehan@chinamobile.com=
> wrote:

> Hi Jacqueline,
>
>
> We have just uploaded a new revision of CATS metrics definition draft(-10=
)
> to reflect your valuable comments regarding to security considerations an=
d
> some general parts.
>
>
>
> https://author-tools.ietf.org/iddiff?url2=3Ddraft-ietf-cats-metric-defini=
tion-10
>
>
> Please help further review if this revision is okay.(Sorry that version
> -09 made no change and was uploaded by mistake.)
>
>
> Best regards,
>
> Kehan (on behalf of co-authors)
>
>
>
> =E5=8F=91=E4=BB=B6=E4=BA=BA=EF=BC=9AJacqueline McCall via Datatracker  <n=
oreply@ietf.org>
> =E6=94=B6=E4=BB=B6=E4=BA=BA=EF=BC=9Asecdir <secdir@ietf.org>
> =E6=8A=84 =E9=80=81: cats <cats@ietf.org>,"draft-ietf-cats-metric-definit=
ion.all" <
> draft-ietf-cats-metric-definition.all@ietf.org>
> =E5=8F=91=E9=80=81=E6=97=B6=E9=97=B4=EF=BC=9A2026-06-09 13:49:01
> =E4=B8=BB=E9=A2=98=EF=BC=9A[Cats] draft-ietf-cats-metric-definition-08 ea=
rly Secdir review
>
> Document: draft-ietf-cats-metric-definition
> Title: CATS Metrics Definition
> Reviewer: Jacqueline McCall
> Review result: Has Issues
>
> I have reviewed this document as part of the security directorate's ongoi=
ng
>
> effort to review all IETF documents being processed by the IESG. These co=
mments
>
> were written primarily for the benefit of the security area directors. Do=
cument
>
> editors and WG chairs should treat these comments just like any other las=
t call
> comments.
>
> The summary of the review is =E2=80=9CHas Issues=E2=80=9D.
>
> Thank you for the opportunity to look over this as an early review. I
>
> appreciate the thought that has been put into the security considerations=
 but
> see opportunities to build this out for a more complete view. Some
> observations/recommendation from a security point of view include:
>
>
> * While the security considerations mention sensitivity of metrics, it mi=
sses
>
> one of the key points. These metrics are control inputs to steering decis=
ions,
> not just telemetry. Incorrect or manipulated metrics could impact service
>
> contact instance selection and forwarding behaviour. Highlighting this wo=
uld
> help frame the section.
>
> * CATS metrics are mentioned in the security considerations as =E2=80=9Cp=
otentially
>
> sensitive=E2=80=9D. This should be greatly strengthened, providing inform=
ation about
> how they might be sensitive (i.e. used to identify), and what unintended
> disclosure/access to these metrics could mean.
>
> * This document provides no discussion around handling stale values.
>
> Requirement seven (R7) in draft-ietf-cats-usecases-requirements-14 states=
 that
> =E2=80=9CCATS systems MUST support staleness handling for CATS metrics an=
d provide
>
> indications of when metrics should be refreshed, so that CATS components =
can
>
> know if a metric value is valid or not=E2=80=9D. Would this require addit=
ional metric
> fields to achieve? A lack of validation raises security concerns.
>
>
> * Following on from the previous point, current security considerations s=
tates
>
> =E2=80=9CFalse reporting SHOULD be mitigated via secondary validation=E2=
=80=9D. Validation as a
>
> whole seems to be missing at the moment and should be covered, before thi=
nking
> about secondary.
>
>
> * Lack of authorisation handling. It is great that authentication is ment=
ioned
> between C-SMA, C-NMA and receivers, but are all values accepted from any
> authenticated source?
>
> Outside of the above security points, more general observations include:
>
> 4.1.  CATS Metric Fields
>
>
> *The *Level* field specifies =E2=80=9CThis field can take two values: 1 f=
or Level 1 and
>
> 2 for Level 2=E2=80=9D.  What happened to Level 0 as defined in Section 3=
.1? =E2=80=9CAppendix
> A. Level 0 Metric Examples=E2=80=9D highlight this as a value that can be=
 used.
>
>
> *The *Source* field is listed as optional.  Section 4. =E2=80=9CCATS Metr=
ics Framework
>
> and Specification=E2=80=9D states under *Metric provenance and transparen=
cy:* that the
>
> =E2=80=9Cframework explicitly captures the origin and context of metrics =
by introducing
> a "Source" field, following the model defined in [RFC9439]=E2=80=9D. Bein=
g optional
> seems at odds with this. All examples also populate this field.
>
>
>
> --
> Cats mailing list -- cats@ietf.org
> To unsubscribe send an email to cats-leave@ietf.org
>
> Subject=EF=BC=9A[Cats] draft-ietf-cats-metric-definition-08 early Secdir =
review
>
> Document: draft-ietf-cats-metric-definition
> Title: CATS Metrics Definition
> Reviewer: Jacqueline McCall
> Review result: Has Issues
>
> I have reviewed this document as part of the security directorate's ongoi=
ng
>
> effort to review all IETF documents being processed by the IESG. These co=
mments
>
> were written primarily for the benefit of the security area directors. Do=
cument
>
> editors and WG chairs should treat these comments just like any other las=
t call
> comments.
>
> The summary of the review is =E2=80=9CHas Issues=E2=80=9D.
>
> Thank you for the opportunity to look over this as an early review. I
>
> appreciate the thought that has been put into the security considerations=
 but
> see opportunities to build this out for a more complete view. Some
> observations/recommendation from a security point of view include:
>
>
> * While the security considerations mention sensitivity of metrics, it mi=
sses
>
> one of the key points. These metrics are control inputs to steering decis=
ions,
> not just telemetry. Incorrect or manipulated metrics could impact service
>
> contact instance selection and forwarding behaviour. Highlighting this wo=
uld
> help frame the section.
>
> * CATS metrics are mentioned in the security considerations as =E2=80=9Cp=
otentially
>
> sensitive=E2=80=9D. This should be greatly strengthened, providing inform=
ation about
> how they might be sensitive (i.e. used to identify), and what unintended
> disclosure/access to these metrics could mean.
>
> * This document provides no discussion around handling stale values.
>
> Requirement seven (R7) in draft-ietf-cats-usecases-requirements-14 states=
 that
> =E2=80=9CCATS systems MUST support staleness handling for CATS metrics an=
d provide
>
> indications of when metrics should be refreshed, so that CATS components =
can
>
> know if a metric value is valid or not=E2=80=9D. Would this require addit=
ional metric
> fields to achieve? A lack of validation raises security concerns.
>
>
> * Following on from the previous point, current security considerations s=
tates
>
> =E2=80=9CFalse reporting SHOULD be mitigated via secondary validation=E2=
=80=9D. Validation as a
>
> whole seems to be missing at the moment and should be covered, before thi=
nking
> about secondary.
>
>
> * Lack of authorisation handling. It is great that authentication is ment=
ioned
> between C-SMA, C-NMA and receivers, but are all values accepted from any
> authenticated source?
>
> Outside of the above security points, more general observations include:
>
> 4.1.  CATS Metric Fields
>
>
> *The *Level* field specifies =E2=80=9CThis field can take two values: 1 f=
or Level 1 and
>
> 2 for Level 2=E2=80=9D.  What happened to Level 0 as defined in Section 3=
.1? =E2=80=9CAppendix
> A. Level 0 Metric Examples=E2=80=9D highlight this as a value that can be=
 used.
>
>
> *The *Source* field is listed as optional.  Section 4. =E2=80=9CCATS Metr=
ics Framework
>
> and Specification=E2=80=9D states under *Metric provenance and transparen=
cy:* that the
>
> =E2=80=9Cframework explicitly captures the origin and context of metrics =
by introducing
> a "Source" field, following the model defined in [RFC9439]=E2=80=9D. Bein=
g optional
> seems at odds with this. All examples also populate this field.
>
>
>
> --
> Cats mailing list -- cats@ietf.org
> To unsubscribe send an email to cats-leave@ietf.org
>
>

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Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr"><div dir=3D"ltr"><p class=3D"MsoNormal" style=3D"backgroun=
d-image:initial;background-position:initial;background-size:initial;backgro=
und-repeat:initial;background-origin:initial;background-clip:initial;margin=
:0cm;font-size:12pt;font-family:Aptos,sans-serif"><span style=3D"color:blac=
k">Hello,=C2=A0</span></p><p class=3D"MsoNormal" style=3D"background-image:=
initial;background-position:initial;background-size:initial;background-repe=
at:initial;background-origin:initial;background-clip:initial;margin:0cm;fon=
t-size:12pt;font-family:Aptos,sans-serif"><span style=3D"color:black"><br><=
/span></p><p class=3D"MsoNormal" style=3D"background-image:initial;backgrou=
nd-position:initial;background-size:initial;background-repeat:initial;backg=
round-origin:initial;background-clip:initial;margin:0cm;font-size:12pt;font=
-family:Aptos,sans-serif"><span style=3D"color:black">Thank you for the pos=
itive engagement with the
feedback and prompt updates to the draft. I have reviewed the latest versio=
n
(draft-ietf-cats-metric-definition-10) and am happy to see how it has
developed.</span><span style=3D"color:black"></span></p><p class=3D"MsoNorm=
al" style=3D"background-image:initial;background-position:initial;backgroun=
d-size:initial;background-repeat:initial;background-origin:initial;backgrou=
nd-clip:initial;margin:0cm;font-size:12pt;font-family:Aptos,sans-serif"><sp=
an style=3D"color:black"><br></span></p>

<p class=3D"MsoNormal" style=3D"background-image:initial;background-positio=
n:initial;background-size:initial;background-repeat:initial;background-orig=
in:initial;background-clip:initial;margin:0cm;font-size:12pt;font-family:Ap=
tos,sans-serif"><span style=3D"color:black">The security considerations sec=
tion now provides
a far better picture of the overall security aspects. The opening paragraph
does a great job of conveying the importance of the security considerations=
 and
sets up the remainder of the section well. The format used to cover the
individual components (integrity, authenticity, controllability, freshness,=
 and
confidentiality) is clear and concise, helping readers step through the
different aspects. I really appreciate the work that was put into building =
this
out.</span><span style=3D"color:black"></span></p><p class=3D"MsoNormal" st=
yle=3D"background-image:initial;background-position:initial;background-size=
:initial;background-repeat:initial;background-origin:initial;background-cli=
p:initial;margin:0cm;font-size:12pt;font-family:Aptos,sans-serif"><span sty=
le=3D"color:black"><br></span></p>

<p class=3D"MsoNormal" style=3D"background-image:initial;background-positio=
n:initial;background-size:initial;background-repeat:initial;background-orig=
in:initial;background-clip:initial;margin:0cm;font-size:12pt;font-family:Ap=
tos,sans-serif"><span style=3D"color:black">As for the suggestions on the C=
ATS Metric
Fields, removing the =E2=80=9Coptional=E2=80=9D wording from *Source* and a=
dding =E2=80=9CLevel 0=E2=80=9D as
an option for *Level* has cleared up any confusion.</span><span style=3D"co=
lor:black"></span></p><p class=3D"MsoNormal" style=3D"background-image:init=
ial;background-position:initial;background-size:initial;background-repeat:i=
nitial;background-origin:initial;background-clip:initial;margin:0cm;font-si=
ze:12pt;font-family:Aptos,sans-serif"><span style=3D"color:black"><br></spa=
n></p>

<p class=3D"MsoNormal" style=3D"background-image:initial;background-positio=
n:initial;background-size:initial;background-repeat:initial;background-orig=
in:initial;background-clip:initial;margin:0cm;font-size:12pt;font-family:Ap=
tos,sans-serif"><span style=3D"color:black">I look forward to seeing how th=
is document
continues to develop as it progresses through the RFC process.</span><span =
style=3D"color:black"></span></p><p class=3D"MsoNormal" style=3D"background=
-image:initial;background-position:initial;background-size:initial;backgrou=
nd-repeat:initial;background-origin:initial;background-clip:initial;margin:=
0cm;font-size:12pt;font-family:Aptos,sans-serif"><span style=3D"color:black=
"><br></span></p><p class=3D"MsoNormal" style=3D"background-image:initial;b=
ackground-position:initial;background-size:initial;background-repeat:initia=
l;background-origin:initial;background-clip:initial;margin:0cm;font-size:12=
pt;font-family:Aptos,sans-serif"><span style=3D"color:black">Thanks</span><=
/p><p class=3D"MsoNormal" style=3D"background-image:initial;background-posi=
tion:initial;background-size:initial;background-repeat:initial;background-o=
rigin:initial;background-clip:initial;margin:0cm;font-size:12pt;font-family=
:Aptos,sans-serif"><span style=3D"color:black">Jacqui</span></p></div><br><=
div class=3D"gmail_quote gmail_quote_container"><div dir=3D"ltr" class=3D"g=
mail_attr">On Mon, Jun 22, 2026 at 8:54=E2=80=AFPM Yao Kehan &lt;<a href=3D=
"mailto:yaokehan@chinamobile.com">yaokehan@chinamobile.com</a>&gt; wrote:<b=
r></div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex=
;border-left:1px solid rgb(204,204,204);padding-left:1ex"><p>Hi Jacqueline,=
</p><p><br></p><p>We have just uploaded a new revision of CATS metrics defi=
nition draft(-10) to reflect your valuable comments regarding to security c=
onsiderations and some general parts.</p><p><br></p><p><a href=3D"https://a=
uthor-tools.ietf.org/iddiff?url2=3Ddraft-ietf-cats-metric-definition-10" ta=
rget=3D"_blank">https://author-tools.ietf.org/iddiff?url2=3Ddraft-ietf-cats=
-metric-definition-10</a></p><p><br></p><p>Please help further review if th=
is revision is okay.(Sorry that version -09 made no change and was uploaded=
 by mistake.)</p><p><br></p><p>Best regards,</p><p>Kehan (on behalf of co-a=
uthors)</p><p><br></p><p class=3D"MsoNormal" style=3D"margin:0cm 0cm 1pt;te=
xt-align:justify;word-break:break-all"><br></p><p>=E5=8F=91=E4=BB=B6=E4=BA=
=BA=EF=BC=9AJacqueline=C2=A0McCall=C2=A0via=C2=A0Datatracker=C2=A0=C2=A0&lt=
;<a href=3D"mailto:noreply@ietf.org" target=3D"_blank">noreply@ietf.org</a>=
&gt;<br>=E6=94=B6=E4=BB=B6=E4=BA=BA=EF=BC=9Asecdir=C2=A0&lt;<a href=3D"mail=
to:secdir@ietf.org" target=3D"_blank">secdir@ietf.org</a>&gt;<br>=E6=8A=84=
=E3=80=80=E9=80=81:=C2=A0cats=C2=A0&lt;<a href=3D"mailto:cats@ietf.org" tar=
get=3D"_blank">cats@ietf.org</a>&gt;,&quot;draft-ietf-cats-metric-definitio=
n.all&quot;=C2=A0&lt;<a href=3D"mailto:draft-ietf-cats-metric-definition.al=
l@ietf.org" target=3D"_blank">draft-ietf-cats-metric-definition.all@ietf.or=
g</a>&gt;<br>=E5=8F=91=E9=80=81=E6=97=B6=E9=97=B4=EF=BC=9A2026-06-09=C2=A01=
3:49:01<br>=E4=B8=BB=E9=A2=98=EF=BC=9A[Cats]=C2=A0draft-ietf-cats-metric-de=
finition-08=C2=A0early=C2=A0Secdir=C2=A0review<br><br>Document:=C2=A0draft-=
ietf-cats-metric-definition<br>Title:=C2=A0CATS=C2=A0Metrics=C2=A0Definitio=
n<br>Reviewer:=C2=A0Jacqueline=C2=A0McCall<br>Review=C2=A0result:=C2=A0Has=
=C2=A0Issues<br><br>I=C2=A0have=C2=A0reviewed=C2=A0this=C2=A0document=C2=A0=
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br>To=C2=A0unsubscribe=C2=A0send=C2=A0an=C2=A0email=C2=A0to=C2=A0<a href=3D=
"mailto:cats-leave@ietf.org" target=3D"_blank">cats-leave@ietf.org</a><br><=
br></p></blockquote></div></div>

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