From: Tarek Saad <tsaad....@gmail.com>
Sent: 14 August 2020 17:30
Thanks Acee. Yes, will do in the next rev we'll push soon.
<tp>
Tarek,
In the same vein, having introductory text to each of the YANG tree diagrams
would have helped me to understand what was intended. As it stands, I reverse
engineer the YANG to find the requirements and lo and behold the YANG meets
those requirements. A few sentences before each tree diagram saying ' this
augments ... so that ... ' would have helped me.
You will find that most routing YANG I-Ds these days follow that pattern
Tom Petch
Tom Petch
Regards,
Tarek
On 8/14/20, 12:29 PM, "mpls on behalf of Acee Lindem (acee)"
<mpls-boun...@ietf.org on behalf of acee=40cisco....@dmarc.ietf.org> wrote:
Hi Tarek,
Can you also add the description of the native MPLS RIB to the text?
Thanks,
Acee
On 8/14/20, 12:27 PM, "mpls on behalf of Acee Lindem (acee)"
<mpls-boun...@ietf.org on behalf of acee=40cisco....@dmarc.ietf.org> wrote:
Hi Tarek,
This works for me.
Thanks,
Acee
On 8/14/20, 12:25 PM, "Tarek Saad" <ts...@juniper.net> wrote:
Hi Acee and Tom,
The authors of ID: draft-ietf-mpls-base-yang met and we discussed
the points below.
We understand that RFC8349 defines an AF-agnostic model for RIBs.
RFC8349 defined only two types of RIBs (IPv4 and IPv6 RIBs), but we envision
other types of RIBs too (e.g. L2 RIB, MCAST RIB, etc.), in addition to MPLS RIB
-- and we hope all such RIBs indeed leverage the generic RIB model introduced
in RFC8349.
We revisited Acee's suggestion and made a small modification (on
top of it) that makes IP routes, MPLS routes (and possibly L2 or MCAST routes
in future) - all have similar MPLS augmentation (in terms of local-label) while
still adhering with RFC8349 to augment with leaf destination-prefix.
augment "/rt:routing/rt:ribs/rt:rib/rt:routes/rt:route" {
when "derived-from-or-self(../../rt:address-family, "
+ "'mpls:mpls')" {
description
"This augment is valid only for native MPLS routes.";
}
description
"This leaf augments a native MPLS route.";
leaf destination-prefix {
type leafref {
path "../local-label";
}
description
"MPLS destination prefix.";
}
}
We follow same approach for the active route RPC and continue to
use a leaf "destination-address" as input (that points to a local-label leaf).
If this is acceptable, we believe the errata 6251 can be rejected
and we'll proceed with the change in the MPLS RIB model.
Regards,
Tarek (for authors)
On 8/11/20, 9:08 AM, "Acee Lindem (acee)" <a...@cisco.com> wrote:
[External Email. Be cautious of content]
Hi Tom, Draft Authors,
The draft could easily be fixed. You just need to:
1. Expand on the single sentence in section 2.1 on the need
for non-IP MPLS routes. Given that the draft wasn't modeled correctly, this
wasn't apparent to most of the reviewers.
2. Add an MPLS AF only augmentation (enforced via a when
statement) to each route for the MPLS AF specific destination-prefix or
destination-address.
3. Limit the current local-label augmentation to non-MPLS AFs.
4. Limit the active-route augmentation to AF MPLS and change
the input to destination-address.
Thanks,
Acee
On 8/11/20, 6:10 AM, "tom petch" <ie...@btconnect.com> wrote:
From: Acee Lindem (acee) <a...@cisco.com>
Sent: 11 August 2020 10:47
Hi Tom,
I fully understood your original comment. There are other
problems with this model. See inline.
On 8/11/20, 4:59 AM, "tom petch" <ie...@btconnect.com>
wrote:
Tarek
Picking up on an earlier point,
________________________________________
From: Tarek Saad <ts...@juniper.net>
Sent: 10 August 2020 21:23
Hi Acee,
The existing RPC is used to query (defined
AFIs=IPv4/IPv6) RIB to return the matching active route identified by a
"destination address".
The MPLS module is trying to reuse this RPC so to query
the MPLS RIB to return the matching active route identified by a "local label".
The RPC defined in RFC 8349 readily accepts MPLS AFI in
it (/rt:routing/rt:ribs/rt:rib/rt:active-route) - unless we augment and
suppress it with a "when check".
IMO, it is reusable as-is but the text below is
limiting the leaf name that identifies an entry in RIB to "destination-address"
only - in MPLS RIB the entry leaf name that identifies an entry is
"local-label".
It is not reusable as is since the augmentation RPC
augmentation must have a when statement restricting it to AF MPLS. Also,
local-label is a leaf which is applicable to all address families. It cannot be
the AF MPLS destination-prefix. This augmentation is missing.
<tp>
I am probably getting out of my depth here, On 1may20 I
raised the issue of why the 'MUST' in the description in RFC8349 was not
enforced in the YANG and 5may20 Martin explained that there is a rule in the
YANG ABNF of input-stmt that makes the obvious impossible:-( You are raising
more profound issues about the RIB that I had not perceived when I reviewed
mpls-base-yang for which I, and I hope everyone else, will be grateful.
If this mpls I-D is to proceed in the immediate future, it
looks like the action may have to be deferred for future study.
More generally, I think that the interaction of forward by
address and forward by label is challenging. When first I looked at the MPLS
I-D I was surprised at the way RFC8349 was augmented. I had not seen MPLS as
an alternative to IPv4 or IPv6 or ... in the way in which the RFC is used
although the RFC does state that it can be; rather, to me, labels are a
different animal, but I assumed that everyone knew what they were doing.
Tom Petch
Thanks,
Acee
<tp>
There should be a 'when' check to enforce the 'MUST'
but the rules of YANG do not allow it in this structure. I raised this on the
NETMOD list at the time of WGLC and Martin pointed me to a rule in the ABNF
which prohibits such a check. He also said that the rule was not needed and
would be a candidate to remove when YANG is revised.
Hence I have always thought of this MUST in the
documentation as a constraint that must be enforced in the YANG
Tom Petch
> action active-route {
> description
> "Return the active RIB route
that is used for the
> destination address.
>
> Address-family-specific
modules MUST augment input
> parameters with a leaf named
'destination-address'.";
Regards,
Tarek
On 8/10/20, 3:27 PM, "Acee Lindem (acee)"
<a...@cisco.com> wrote:
[External Email. Be cautious of content]
All (Speaking as an author of RFC 8349),
I just looked at this in more detail and I don't
think the ietf-mpls.yang model should be augmenting the
/rt:routing/rt:ribs/rt:rib/rt:active-route RPC. The intent of the RPC is to
return the address-family specific active-route corresponding to the
destination-address. This model attempts to overload this RPC with a different
action all together - returning a route that has the local-label as an optional
attribute. I'd reject the Errata and believe the augmentation should be removed
from ietf-mpl.yang. Whether it is replaced with a different one is up to the
co-authors of ietf-mpls.yang.
Thanks,
Acee
On 8/10/20, 2:29 PM, "Rob Wilton (rwilton)"
<rwil...@cisco.com> wrote:
[Resend to hopefully pass recipient limit
filter]
Hi Tom,
I would be interested to hear from the original
authors.
My impression is that this is a technically
reasonable change, but I don't think that an erratum can create a new revision
of a YANG module.
If this erratum was processed as "Hold for
document update" then would that be sufficient to do the right thing in the
MPLS YANG module?
Regards,
Rob
> -----Original Message-----
> From: tom petch <ie...@btconnect.com>
> Sent: 10 August 2020 17:32
> To: RFC Errata System
<rfc-edi...@rfc-editor.org>; lho...@nic.cz; Acee
> Lindem (acee) <a...@cisco.com>;
yingzhen...@huawei.com; war...@kumari.net;
> Rob Wilton (rwilton) <rwil...@cisco.com>;
joe...@bogus.com;
> kent+i...@watsen.net; lber...@labn.net
> Cc: ts...@juniper.net; netmod@ietf.org
> Subject: Re: [netmod] [Technical Errata
Reported] RFC8349 (6251)
>
> From: netmod <netmod-boun...@ietf.org> on
behalf of RFC Errata System
> <rfc-edi...@rfc-editor.org>
> Sent: 07 August 2020 16:45
>
> <tp>
> This is the erratum of whose arrival I
speculated on this list on June
> 16th.
>
> There is a degree of urgency about it. The
I-D in question is mpls-base-
> yang, currently in IETF Last Call, which is a
Normative dependency of bfd-
> yang which is a Normative dependency for a
small mountain of I-D which
> have been waiting a year or so (e.g.
ospf-yang).
>
> I suspect that the technically perfect
solution would involve a YANG
> union, choice or some such structure but as I
said in my Last Call comment
> I can live with a label that contains such as
'address' encompassing such
> as 'label' in the context of forwarding. I
take labels to mean what
> labels mean rather than what I might find in
a work of reference.
>
> Tom Petch
>
> The following errata report has been
submitted for RFC8349,
> "A YANG Data Model for Routing Management
(NMDA Version)".
>
> --------------------------------------
> You may review the report below and at:
>
https://urldefense.com/v3/__https://www.rfc-editor.org/errata/eid6251__;!!NEt6yMaO-gk!URK5WVsqD5g7WpzCU1VuzKJA0AUiawXBFLB_gENlsYMrpiMqDtyFoxw8DnSr2A$
>
> --------------------------------------
> Type: Technical
> Reported by: Tarek Saad <ts...@juniper.net>
>
> Section: 7
>
> Original Text
> -------------
> The RPC "active-route" is used to retrieve
the active route in a RIB.
> RFC8349 defined two AFIs (v4/v6).
>
> draft-ietf-mpls-base-yang is defining a new
RIB AFI for MPLS as per
> section 3 in RFC8349.
>
> The RPC has a "MUST" statement that all RIBs
must augment input
> parameters with a leaf named
'destination-address'.
>
> For MPLS RIB, it makes sense to augment with
leaf named 'local-label'
> since MPLS routes are identified by MPLS
label.
>
> We ask to make the following change:
>
> OLD:
> action active-route {
> description
> "Return the active RIB route
that is used for the
> destination address.
>
> Address-family-specific
modules MUST augment input
> parameters with a leaf named
'destination-address'.";
>
>
> Corrected Text
> --------------
> NEW:
> action active-route {
> description
> "Return the active RIB route
that is used for the
> destination address.
>
> Address-family-specific
modules MUST augment input
> parameters with a suitable
leaf that identifies the
> route.";
>
>
> Notes
> -----
>
>
> Instructions:
> -------------
> This erratum is currently posted as
"Reported". If necessary, please
> use "Reply All" to discuss whether it should
be verified or
> rejected. When a decision is reached, the
verifying party
> can log in to change the status and edit the
report, if necessary.
>
> --------------------------------------
> RFC8349 (draft-ietf-netmod-rfc8022bis-11)
> --------------------------------------
> Title : A YANG Data Model for
Routing Management (NMDA
> Version)
> Publication Date : March 2018
> Author(s) : L. Lhotka, A. Lindem,
Y. Qu
> Category : PROPOSED STANDARD
> Source : Network Modeling
> Area : Operations and
Management
> Stream : IETF
> Verifying Party : IESG
>
>
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