Re: [Lsr] Benjamin Kaduk's Discuss on draft-ietf-isis-yang-isis-cfg-40: (with DISCUSS and COMMENT)
Hi Ben,
Thanks for the excellent review - see one inline.
On 10/8/19, 6:13 AM, "Benjamin Kaduk" wrote:
Hi Stephane,
Thanks for pulling in the fixes; just a few notes inline (and trimming)...
On Tue, Oct 08, 2019 at 10:33:49AM +0200, slitkows.i...@gmail.com wrote:
> Hi Benjamin,
>
> Thanks for your comment.
> Please find some inline answers.
> I'm doing the changes as part of the -41.
>
>
> Stephane
>
> -Original Message-
> From: Benjamin Kaduk via Datatracker
> Sent: mercredi 2 octobre 2019 03:17
> To: The IESG
> Cc: draft-ietf-isis-yang-isis-...@ietf.org; Yingzhen Qu
; aretana.i...@gmail.com; lsr-cha...@ietf.org;
yingzhen.i...@gmail.com; lsr@ietf.org
> Subject: Benjamin Kaduk's Discuss on draft-ietf-isis-yang-isis-cfg-40:
(with DISCUSS and COMMENT)
>
[...]
>
>
> In the "protection-available" container, is there some sort of constraint
that two of the alternate-metrics add up to the third?
> [SLI] It is not really a constraint from a YANG point of view, these are
operational counters.
Sorry, I shouldn't have used the word "constraint", since that's a YANG
verb. I was just asking if the description should reiterate to the reader
that in normal circumstances the two will add up to the third (and "no" is
a fine answer).
[...]
>container delay-metric {
> leaf metric {
>type std-metric;
>description "IS-IS delay metric for IPv4 prefix";
> }
> leaf supported {
>type boolean;
>
> Should the "metric" leaf be conditional on "supported" being true?
> (Same for the other flavors of metric, as well as when they appear later
on in the "neighbor" grouping.)
>
>
> [SLI] This is not a configuration leaf, so I don't think that there is a
need for enforcement at YANG level.
Oh, I had missed that it was config false; sorry about that.
[...]
>
>container unidirectional-link-delay-variation {
> description
>"Container for the average delay variation
>from the local neighbor to the remote one.";
> leaf value {
>type uint32;
>units usec;
>description
> "Delay variation value expressed in microseconds.";
>
> Is this a standard deviation (variance), mean absolute error, ...?
> [SLI] We just mimic what is defined in RFC8570. As the reference is
defined in the model. People should refer to it for more details.
> Moreover this is a pure operational state.
https://tools.ietf.org/html/rfc8570#section-4.3 still leaves me a little
unclear about what exactly is being reported (it sounds like it's just an
average link delay so the word "variation" confuses me), but I agree that
we should not say any more in this document.
>container unidirectional-link-loss {
> [...]
> leaf value {
>type uint32;
>units percent;
>description
> "Link packet loss expressed as a percentage
> of the total traffic sent over a configurable interval.";
>
> This document is all about specifying configuration. How do I configure
the interval in question?
> [SLI] This is an operational state.
The leaf value is operational state, yes, but it reports a valid computed
"over a configurable interval". How do I configure that interval?
I don't disagree that there is more configuration and state associated with
these traffic metrics. However, these are not really under the purview of this
model since IS-IS (and OSPF for that matter) are only serving as a mechanism to
advertise these traffic metrics.
Thanks,
Acee
Thanks!
-Ben
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Re: [Lsr] Benjamin Kaduk's Discuss on draft-ietf-isis-yang-isis-cfg-40: (with DISCUSS and COMMENT)
Hi Benjamin,
Thanks for your comment.
Please find some inline answers.
I'm doing the changes as part of the -41.
Stephane
-Original Message-
From: Benjamin Kaduk via Datatracker
Sent: mercredi 2 octobre 2019 03:17
To: The IESG
Cc: draft-ietf-isis-yang-isis-...@ietf.org; Yingzhen Qu
; aretana.i...@gmail.com; lsr-cha...@ietf.org;
yingzhen.i...@gmail.com; lsr@ietf.org
Subject: Benjamin Kaduk's Discuss on draft-ietf-isis-yang-isis-cfg-40: (with
DISCUSS and COMMENT)
Benjamin Kaduk has entered the following ballot position for
draft-ietf-isis-yang-isis-cfg-40: Discuss
When responding, please keep the subject line intact and reply to all email
addresses included in the To and CC lines. (Feel free to cut this introductory
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Please refer to https://www.ietf.org/iesg/statement/discuss-criteria.html
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The document, along with other ballot positions, can be found here:
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--
DISCUSS:
--
Perhaps the most minor thing that could be Discuss-level, and should be trivial
to resolve, but:
The "i-e" leaf in groupings prefix-ipv4-std and neighbor does not say whether
boolean value true corresponds to internal or external.
[SLI] Right, I have added the following statement in the description:
"Set to false to indicate an internal metric"
--
COMMENT:
--
Section 1
This document defines a YANG [RFC7950] data model for IS-IS routing
protocol.
nit: "the IS-IS routing protocol"
[SLI] Fixed
Section 2.8
This YANG module supports LFA (Loop Free Alternates) [RFC5286] and
remote LFA [RFC7490] as IP Fast Re-Route (FRR) techniques. The
"fast-reroute" container may be augmented by other models to support
other IP FRR flavors (MRT, TI-LFA, etc.).
If we're going to give examples of other flavors, do we want to have
informative references for them? (This is particularly relevant since we
define enumeration values for them in the "alternate-type"
enumeration.)
[SLI] Sounds good, I have added some references.
Section 6
identity lsp-attached-default-metric-flag {
base lsp-flag;
description "Set when originator is attached to
another area using the referred metric.";
nit(?): I'm not sure whether the "referred" in the description is appropriate
given the "default" in the identity name.
[SLI] Fixed
feature ldp-igp-sync {
description
"LDP IGP synchronization.";
nit: the surrounding context suggests that "Support for" would give a more
consistent style. Maybe for auto-cost, te-rid, max-ecmp, lsp-refresh, and
admin-control as well.
[SLI] Fixed
feature nlpid-control {
description
"This feature controls the advertisement
of support NLPID within IS-IS configuration.";
nit: "support for"
[SLI] Fixed
feature maximum-area-addresses {
description
"Support of maximum-area-addresses config.";
nit: s/of/for/
[SLI] Fixed
leaf alternate-type {
type enumeration {
[...]
enum other {
description
"Unknown alternate type.";
Do I remember correctly that enumerations are not extensible in the future? I
don't know how relevant that would be here, though.
[SLI] Right, I have changed to identity
In the "protection-available" container, is there some sort of constraint that
two of the alternate-metrics add up to the third?
[SLI] It is not really a constraint from a YANG point of view, these are
operational counters.
container unprotected-routes {
config false;
list address-family-stats {
nit: the name/description of address-family-stats doesn't match up with the
parent container that just claims to be a list of unprotected prefixes (no
stats).
[SLI] I agree, I have changed the address-family-stats to "prefixes"
list protection-statistics {
side note: I wonder whether the various uint32 leaves are better as
gauge32 than plain uint32.
Also, perhaps the description could mention a relationship bteween
total-routes/protected-routes+unprotected-routes, and/or
protected-routes/link-protected-routes+node-protected-routes.
grouping route-content {
[...]
leaf-list tag {
type uint64;
description
"List of tags associated with the route. The leaf
describes both 32-bit and 64-bit tags.";
Are these the admin tags from RFC 5130? Where is it specified that the
32- and 64-bit variants are just different views into a single consolidated tag
namespace?
[SLI] Right, I have added a better description.
[Lsr] Benjamin Kaduk's Discuss on draft-ietf-isis-yang-isis-cfg-40: (with DISCUSS and COMMENT)
Benjamin Kaduk has entered the following ballot position for
draft-ietf-isis-yang-isis-cfg-40: Discuss
When responding, please keep the subject line intact and reply to all
email addresses included in the To and CC lines. (Feel free to cut this
introductory paragraph, however.)
Please refer to https://www.ietf.org/iesg/statement/discuss-criteria.html
for more information about IESG DISCUSS and COMMENT positions.
The document, along with other ballot positions, can be found here:
https://datatracker.ietf.org/doc/draft-ietf-isis-yang-isis-cfg/
--
DISCUSS:
--
Perhaps the most minor thing that could be Discuss-level, and should be
trivial to resolve, but:
The "i-e" leaf in groupings prefix-ipv4-std and neighbor does not say
whether boolean value true corresponds to internal or external.
--
COMMENT:
--
Section 1
This document defines a YANG [RFC7950] data model for IS-IS routing
protocol.
nit: "the IS-IS routing protocol"
Section 2.8
This YANG module supports LFA (Loop Free Alternates) [RFC5286] and
remote LFA [RFC7490] as IP Fast Re-Route (FRR) techniques. The
"fast-reroute" container may be augmented by other models to support
other IP FRR flavors (MRT, TI-LFA, etc.).
If we're going to give examples of other flavors, do we want to have
informative references for them? (This is particularly relevant since
we define enumeration values for them in the "alternate-type"
enumeration.)
Section 6
identity lsp-attached-default-metric-flag {
base lsp-flag;
description "Set when originator is attached to
another area using the referred metric.";
nit(?): I'm not sure whether the "referred" in the description is
appropriate given the "default" in the identity name.
feature ldp-igp-sync {
description
"LDP IGP synchronization.";
nit: the surrounding context suggests that "Support for" would give a
more consistent style. Maybe for auto-cost, te-rid, max-ecmp,
lsp-refresh, and admin-control as well.
feature nlpid-control {
description
"This feature controls the advertisement
of support NLPID within IS-IS configuration.";
nit: "support for"
feature maximum-area-addresses {
description
"Support of maximum-area-addresses config.";
nit: s/of/for/
leaf alternate-type {
type enumeration {
[...]
enum other {
description
"Unknown alternate type.";
Do I remember correctly that enumerations are not extensible in the
future? I don't know how relevant that would be here, though.
In the "protection-available" container, is there some sort of
constraint that two of the alternate-metrics add up to the third?
container unprotected-routes {
config false;
list address-family-stats {
nit: the name/description of address-family-stats doesn't match up with
the parent container that just claims to be a list of unprotected
prefixes (no stats).
list protection-statistics {
side note: I wonder whether the various uint32 leaves are better as
gauge32 than plain uint32.
Also, perhaps the description could mention a relationship bteween
total-routes/protected-routes+unprotected-routes, and/or
protected-routes/link-protected-routes+node-protected-routes.
grouping route-content {
[...]
leaf-list tag {
type uint64;
description
"List of tags associated with the route. The leaf
describes both 32-bit and 64-bit tags.";
Are these the admin tags from RFC 5130? Where is it specified that the
32- and 64-bit variants are just different views into a single
consolidated tag namespace?
grouping authentication-global-cfg {
I see how "global" is in contrast to a smaller scope (hello, interface,
adjacency, etc.) both here and elsewhere, but when we have a global
defeault as well as per-level configuration that use the same grouping,
it ceases to be universally "global". But, it's probably too late to be
worth changing so many names just for aesthetics...
leaf poi-tlv {
if-feature poi-tlv;
type boolean;
default false;
description
"Enable advertisement of IS-IS purge TLV.";
nit(?): I thought the purge origin identification TLV was an extension
to the generic purge capability but this description ("purge TLV") is
very generic.
Should any of the uint32 leaves in "packet-counters" instead be of type
counter32?
grouping spf-log {
[...]
leaf id {
type uint32;
description
"Event identifier - purely internal value.";
Is there anything
