RE: [pim] Yangdoctors last call review of draft-ietf-pim-igmp-mld-yang-07

[Guofeng <guofeng@xxxxxxxxxx>]

Hi Jan,

 

Please find attached draft-08 updated according to the comments #2 ~ #7, while Xufeng and you had discussed about comment #1.

Please review the draft, thanks a lot.

 

Feng

 

-----Original Message-----

From: Jan Lindblad [mailto:janl@xxxxxxxxxx]

Sent: Monday, August 13, 2018 10:35 PM

To: yang-doctors@xxxxxxxx

Cc: ietf@xxxxxxxx; pim@xxxxxxxx; draft-ietf-pim-igmp-mld-yang.all@xxxxxxxx

Subject: Yangdoctors last call review of draft-ietf-pim-igmp-mld-yang-07

 

Reviewer: Jan Lindblad

Review result: On the Right Track

 

This is my YANG-doctor review of draft-ietf-pim-igmp-mld-yang-07. In the spring, I did an early review of the -02 version.

 

Most of the comments from the earlier review are still valid. In some ways the document has progressed since -02, in many it has not, and in a few it has deteriorated. In my judgement, the document is not ready for last call. Many fundamentally important questions are still unresolved. Here are my review comments in rough falling order of importance.

 

#1 Improper augment of /rt:routing/rt:control-plane-protocols

 

Quoted from section 3.1:

   This model augments the core routing data model "ietf-routing"

   specified in [RFC8349].  The IGMP model augments "/rt:routing/

   rt:control-plane-protocols" as opposed to augmenting "/rt:routing/

   rt:control-plane-protocols/rt:control-plane-protocol", as the latter

   would allow multiple protocol instances, while the IGMP protocol is

   designed to be enabled or disabled as a single protocol instance on

   a network instance or a logical network element.

 

The description above, and the actual augment statements in the YANG module violate the principles described in RFC 8349, the ietf-routing.yang module it augments. In RFC 8349, section 5.3.  Control-Plane Protocol, the proper way of augmenting the routing module is described. The fact that this is a singleton protocol instance doesn't change this. Section 5.3 describes singleton cases as well.

 

Guofeng: Xufeng has discussed with Jan about the comment, and it is closed.

 

#2 Incorrect vendor refinement model

 

Quoted from section 2.2:

   For the same reason, wide constant ranges (for example, timer

   maximum and minimum) will be used in the model.  It is expected that

   vendors will augment the model with any specific restrictions that

   might be required. Vendors may also extend the features list with

   proprietary extensions.

 

This is not acceptable. The principle suggested does not foster interoperability and useful standards. It is also not possible to do what the paragraph suggests in YANG. This was pointed out in the -02 review, and a suggestion was given there on how to address the problem.

 

Guofeng: We removed the paragraph above, and put the values discussed by Mcast Design Team.

 

 

#3 Top level structures not optional

 

Quoted from section 2.3:

   The current document contains IGMP and MLD as separate schema

   branches in the structure. The reason for this is to make it easier

   for implementations which may optionally choose to support specific

   address families. And the names of objects may be different between

   the IPv4 (IGMP) and IPv6 (MLD) address families.

 

This problem was also pointed out in the -02 review. The author suggests that implementing igmp and/or mld is optional. This is not reflected in the YANG module, however. As currently modeled, both are currently mandatory to implement. If-feature is used liberally in the module, and could be used here as well.

 

#4 Unclear meaning of optional leaves

 

Quoted from section 3.1:

   Where fields are not genuinely essential to protocol operation, they

   are marked as optional. Some fields will be essential but have a

   default specified, so that they need not be configured explicitly.

 

In fact, in the current version of the module, every leaf is optional (except keys, which cannot be optional). It is good to see the addition of defaults in many cases, but many unclear cases remain. E.g. leaf /igmp/global/enable is of type boolean. I understand what true and false implies for this leaf. But what does it mean if it is not set at all? Either add a default or describe the meaning in the description. Similarly, if the leaf version is not set on an igmp or mld interface, or on the interface-global level, what does that mean?

Add default. require-router-alert? explicit-tracking? exclude-lite? Many of these are used in NP-containers inheriting all the from the root, which makes the use of mandatory highly discouraged in the current form. If the RFC 8349 augmentation principles are followed, the concern around mandatory falls, and some leafs with no sensible default could be marked mandatory instead.

 

#5 All optional state

 

All state data is optional, which means a conforming server could very well decide not to implement it. E.g. discontinuity-time is optional. Should a manager count on this being available? A situation where every leaf is optional is as nice and flexible for server implementors as it is frustrating and complicated for manager implementors to consume. A YANG model is an API contract and should consider the needs of both sides. The way this has been designed reveals that no representation for the consumer side of this model has been involved in the design. I would suggest thinking through what is the most essential state data for a manager, and make some leafs mandatory.

 

#6 Abundant copy-paste

 

There is abundant repetition in the YANG module. leaf version is defined 2 times for igmp with identical definitions, and two more for mld with identical definitions. leaf enable is defined once for the interface global-level, and with identical definition on the interface local level. leaf last-member-query-interval, query-interval and half a dozen other leaves are defined twice with identical definitions.

 

#7 Leaf interface in the rpc clear*groups on line 1124, 1094 has type string.

Should be a leafref? Describe what values are valid. #8 Leaf group-policy, source-policy on line 486, 527, 624, 689: type string. Should be leafref?

Describe what values are valid. #9 Leaf group on line 705, 1101, 1131: Is any

ipv4/6 address ok, or only a multicast address? Model accordingly.

 

 

 

 

 

 

From: pim [mailto:pim-bounces@xxxxxxxx] On Behalf Of Jan Lindblad
Sent: Tuesday, September 11, 2018 9:52 PM
To: Xufeng Liu <xufeng.liu.ietf@xxxxxxxxx>
Cc: yang-doctors@xxxxxxxx; ietf <ietf@xxxxxxxx>; pim@xxxxxxxx; draft-ietf-pim-igmp-mld-yang.all@xxxxxxxx
Subject: Re: [pim] Yangdoctors last call review of draft-ietf-pim-igmp-mld-yang-07

 

Xufeng,

 

Thanks for the review and valuable comments.

 

In regard to item #1, there was a discussion thread among the Yang Doctors, authors of RFC 8349, and Routing Area Yang Architecture Design Team, as attached below.  The discussion occurred during the review of a draft with the same issue as this one.

 

I see, didn't know. Good. If this has been discussed to conclusion, then you should of course go with that decision.

 

As mentioned earlier, there are a few other singleton protocols mapped into this structure, e.g. static. I think it would make sense to treat this the same. Principle of least astonishment.

 

Best Regards,

/jan

 

 

================================

原始邮件
发件人：XufengLiu <Xufeng_Liu@xxxxxxxxx>
收件人：Acee Lindem (acee) <acee@xxxxxxxxx>Christian Hopps <chopps@xxxxxxxxxx>Martin Bjorklund <mbj@xxxxxxxxxx>
抄送人：张征00007940;yang-doctors@xxxxxxxx <yang-doctors@xxxxxxxx>
日 期 ：2018年02月20日 22:30
主 题 ：RE: [yang-doctors] How to restrict to have singlecontrol-plane-protocol instance
Using "" as the name is better, but I am not sure that it is good enough. When we use ConfD to translate the model to a command line, if the option "tailf:cli-expose-key-name" is not used, we will have:

edit routing control-plane-protocols control-plane-protocol type msdp name ''"

If the option "tailf:cli-expose-key-name" is used, we will have:

edit routing control-plane-protocols control-plane-protocol msdp ''"

I am pretty sure that we would get a bug report on this, asking what is the purpose to have: name ''", and requesting a suppression on the term, but we do not have a good way to achieve.

As a comparison, the option #3 will give:

edit routing control-plane-protocols msdp

This is the only acceptable solution so far. When a model is not usable by the end-user, other considerations (such as augmentation convenience) will not matter.

Thanks,
- Xufeng

> -----Original Message-----
> From: Acee Lindem (acee) [mailto:acee@xxxxxxxxx]
> Sent: Monday, February 19, 2018 1:35 PM
> To: Christian Hopps <chopps@xxxxxxxxxx>; Martin Bjorklund <mbj@xxxxxxxxxx>
> Cc: Xufeng Liu <Xufeng_Liu@xxxxxxxxx>; zhang.zheng@xxxxxxxxxx; yang-
> doctors@xxxxxxxx
> Subject: Re: [yang-doctors] How to restrict to have single control-plane-
> protocol instance
>
>
>
> On 2/19/18, 5:02 AM, "Christian Hopps" <chopps@xxxxxxxxxx> wrote:
>
>
>     Martin Bjorklund <mbj@xxxxxxxxxx> writes:
>
>     > Hi,
>     >
>     > "Acee Lindem (acee)" <acee@xxxxxxxxx> wrote:
>     >> All,
>     >>
>     >> As seems to be the modus operandi for YANG issues, we have 3 separate
> opinions as to how a protocol only supporting a single instance should be
> realized.
>     >>
>     >>   1. Augment the existing control plane protocols list (RFC 8022BIS)
>     >>   and specify in the description text that only a single instance is
>     >>   supported.
>     >>   2. Augment the existing control plane protocols list (RFC 8022BIS)
>     >>   and use a YANG 1.1 must() restriction as discussed by Martin and
>     >>   Lada.
>     >>   3. Augment the container one level up from the list for singleton
>     >>   protocols (suggested by Xufeng).
>
>     > But I think there was also a proposal to require the single instance
>     > to have a well-known name - but maybe this proposal is no longer on
>     > the table.
>
>     I actually liked this solution; however, instead of picking an arbitrary "well-
> known" value for name, I would specify the 0 length string instead. I think that
> reinforces the idea that this isn't actually a named instance. :)
>
>        augment "/rt:routing/rt:control-plane-protocols/"
>              + "rt:control-plane-protocol" {
>           when "derived-from-or-self(rt:type, 'msdp:msdp') and rt:name = ''"  {
>           container msdp {
>
> One benefit of this solution is that it solves Xufeng's issue of what the client uses
> as the instance name.
>
>
>     Thanks,
>     Chris.
>
>     >
>     >
>     > /martin
>     >
>     >
>     >> and #3. For #3, one determent would be that the control plane protocols
> are in a location other than where they were originally envisioned and I don't
> relish pulling RFC8022BIS off the RFC queue to document.
>     >>
>     >> Thanks,
>     >> Acee
>     >>
>     >> On 2/15/18, 8:39 AM, "Reshad Rahman (rrahman)" <rrahman@xxxxxxxxx>
> wrote:
>     >>
>     >>     Hi Xufeng,
>     >>
>     >>     I think the intent of 8022bis was to have all protocols under
> /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol. I agree that
> forcing a name for a single-instance is cumbersome, but I think it is too late to
> change tree hierachy organization at this point.
>     >>
>     >>     I will defer to other YDs and 8022bis authors on this.
>     >>
>     >>     Regards,
>     >>     Reshad.
>     >>
>     >>     On 2018-02-08, 9:48 AM, "Xufeng Liu" <Xufeng_Liu@xxxxxxxxx> wrote:
>     >>
>     >>         Hi All,
>     >>
>     >>         I feel that such a solution is still not clean enough to outweigh the
> simple augmentation to "/rt:routing/rt:control-plane-protocols/".
>     >>
>     >>         Some considerations are:
>     >>
>     >>         - Name management: Neither the operator nor the implementation
> wants to deal with the artificial name, whether it is hardcoded, user-configured,
> or system-generated. When we implement such singleton protocol, we don't
> save a name anywhere.
>     >>         - The complexity of validation: The "when" statement is an
> unnecessary expense to the user and to the implementation, especially if we
> need to check all instances.
>     >>         - Data tree query: If the singleton "MSDP" is mixed with other protocol
> instances, it is less obvious or harder to search for. Depending on the
> implementation, it would be worse if the entire list needs to be iterated.
>     >>         - Tree hierarchy  organization: I don't see too big a problem with "all
> single-instance protocols under /rt:routing/rt:control-plane-protocols and all
> the multi-instance ones under /rt:routing/rt:control-plane-protocols/rt:control-
> plane-protocol". If necessary, some of the names can be adjusted.
>     >>
>     >>         Thanks,
>     >>         - Xufeng
>     >>
>     >>
>     >>         > -----Original Message-----
>     >>         > From: Reshad Rahman (rrahman) [mailto:rrahman@xxxxxxxxx]
>     >>         > Sent: Thursday, February 8, 2018 9:41 AM
>     >>         > To: Ladislav Lhotka <lhotka@xxxxxx>; Martin Bjorklund <mbj@tail-
> f.com>;
>     >>         > Acee Lindem (acee) <acee@xxxxxxxxx>
>     >>         > Cc: yang-doctors@xxxxxxxx; zhang.zheng@xxxxxxxxxx; Xufeng Liu
>     >>         > <Xufeng_Liu@xxxxxxxxx>
>     >>         > Subject: Re: [yang-doctors] How to restrict to have single control-
> plane-
>     >>         > protocol instance
>     >>         >
>     >>         > Thanks for the suggestions. I agree that hard-coding the name is a
> bad idea,
>     >>         > glad that a cleaner way of doing this is possible.
>     >>         > - We can move the must statement up to restrict max of 1 control-
> plane-
>     >>         > protocol instance of type msdp?
>     >>         > - Acee/Lada, should a note be added to section 5.3 of 8022bis
> regarding how
>     >>         > to enforce single instance? How much of a concern is the
> performance
>     >>         > impact in this specific case?
>     >>         >
>     >>         > Regards,
>     >>         > Reshad.
>     >>         >
>     >>         > On 2018-02-08, 7:02 AM, "Ladislav Lhotka" <lhotka@xxxxxx> wrote:
>     >>         >
>     >>         >     On Thu, 2018-02-08 at 12:39 +0100, Martin Bjorklund wrote:
>     >>         >     > "Acee Lindem (acee)" <acee@xxxxxxxxx> wrote:
>     >>         >     > > Hi Lada,
>     >>         >     >
>     >>         >     > >
>     >>         >     >
>     >>         >     > > On 2/8/18, 4:42 AM, "yang-doctors on behalf of Ladislav
> Lhotka"
>     >>         > <yang-docto
>     >>         >     > rs-bounces@xxxxxxxx on behalf of lhotka@xxxxxx> wrote:
>     >>         >     >
>     >>         >     > >
>     >>         >     >
>     >>         >     > >     On Thu, 2018-02-08 at 09:20 +0100, Martin Bjorklund wrote:
>     >>         >     >
>     >>         >     > >     > Hi,
>     >>         >     >
>     >>         >     > >     >
>     >>         >     >
>     >>         >     > >     > "Reshad Rahman (rrahman)" <rrahman@xxxxxxxxx> wrote:
>     >>         >     >
>     >>         >     > >     > > Hi YDs,
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > > MSDP YANG authors want to enforce single-instance of
> MSDP
>     >>         >     >
>     >>         >     > >     > > control-plane protocol. The when “rt:type =
> ‘msdp’“ allows
>     >>         > multiple
>     >>         >     >
>     >>         >     > >     > > control-pane-protocol instances as long as they have
> different
>     >>         >     >
>     >>         >     > >     > > rt:name. The only workaround I thought of is to have a
> when
>     >>         >     > statement
>     >>         >     >
>     >>         >     > >     > > on the name in the top level container. This would still
> multiple
>     >>         >     >
>     >>         >     > >     > > control-plane-protocol instance of type msdp but
> restricts the
>     >>         > name
>     >>         >     > to
>     >>         >     >
>     >>         >     > >     > > a fixed name (msdp-protocol in this case) for the top level
> msdp
>     >>         >     >
>     >>         >     > >     > > container to exist. Any suggestions on how to do this
> better?
>     >>         >     >
>     >>         >     > >     >
>     >>         >     >
>     >>         >     > >     > Hard-coding a name like this is IMO a bad idea.
>     >>         >     >
>     >>         >     > >     >
>     >>         >     >
>     >>         >     > >     > Better would be to simply state in text that there MUST
> only be one
>     >>         >     >
>     >>         >     > >     > instance of this type.
>     >>         >     >
>     >>         >     > >     >
>     >>         >     >
>     >>         >     > >     > But you can also add a must statement that enforces this:
>     >>         >     >
>     >>         >     > >     >
>     >>         >     >
>     >>         >     > >     >    augment "/rt:routing/rt:control-plane-protocols/"
>     >>         >     >
>     >>         >     > >     >          + "rt:control-plane-protocol" {
>     >>         >     >
>     >>         >     > >     >       when 'derived-from-or-self(rt:type, "msdp:msdp"'  {
>     >>         >     >
>     >>         >     > >     >      container msdp {
>     >>         >     >
>     >>         >     > >     >        must 'count(/rt:routing/rt:control-plane-protocols/'
>     >>         >     >
>     >>         >     > >     >           + '      rt:control-plane-protocol['
>     >>         >     >
>     >>         >     > >     >           + '        derived-from-or-sel(../rt:type, "msdp:msdp")])
> <=
>     >>         >     > 1'";
>     >>         >     >
>     >>         >     > >     >
>     >>         >     >
>     >>         >     > >     >
>     >>         >     >
>     >>         >     > >     > In general, you should be careful with the usage of "count",
> since it
>     >>         >     >
>     >>         >     > >     > will loop through *all* instances in the list every time.  If
> the list
>     >>         >     >
>     >>         >     > >     > is big, this can have a performance impact.
>     >>         >     >
>     >>         >     > >
>     >>         >     >
>     >>         >     > >     Instead of count(), it is possible to use the so-called
> Muenchian
>     >>         >     > method:
>     >>         >     >
>     >>         >     > >
>     >>         >     >
>     >>         >     > >         container msdp {
>     >>         >     >
>     >>         >     > >           must "not(../preceding-sibling::rt:control-plane-
> protocol["
>     >>         >     >
>     >>         >     > >              + "derived-from-or-self(rt:type, 'msdp:msdp')])";
>     >>         >     >
>     >>         >     > >           ..
>     >>         >     >
>     >>         >     > >         }
>     >>         >     >
>     >>         >     > >
>     >>         >     >
>     >>         >     > >     It basically states that the control-plane-protocol containing
> the
>     >>         >     > "msdp"
>     >>         >     >
>     >>         >     > >     container must not be preceded with a control-plane-
> protocol entry
>     >>         > of
>     >>         >     > the
>     >>         >     >
>     >>         >     > >     msdp:msdp type (or derived).
>     >>         >     >
>     >>         >     > >
>     >>         >     >
>     >>         >     > > This looks like an elegant solution.
>     >>         >     >
>     >>         >     >
>     >>         >     > "elegant" as in "less obvious" ;)  It has the same time complexity
> as
>     >>         >     > the count() solution.
>     >>         >
>     >>         >     It should be faster on the average - it has to scan only preceding
> siblings of
>     >>         >     the MSDP protocol instance whereas count() always has to check
> *all*
>     >>         > protocol
>     >>         >     instances.
>     >>         >
>     >>         >     It is true though that in XSLT this technique can be made
> considerably
>     >>         > more
>     >>         >     efficient by using indexed keys.
>     >>         >
>     >>         >     Lada
>     >>         >
>     >>         >     >
>     >>         >     >
>     >>         >     > However, since the key for the control-plane-protocol  list is
> "type
>     >>         >     > name", won't it only work if the previous sibling has a  "name"
> that
>     >>         >     > is precedes the one being added?
>     >>         >     >
>     >>         >     > For each list entry that has this container, the _expression_ is
>     >>         >     > evaluated.  It will scan all preceding entries and ensure that there
>     >>         >     > are none with this type.  So the order of the entries doesn't
> matter;
>     >>         >     > if there are two with the same type, one of them has to be
> before the
>     >>         >     > other.
>     >>         >     >
>     >>         >     >
>     >>         >     > /martin
>     >>         >     >
>     >>         >     >
>     >>         >     > >
>     >>         >     >
>     >>         >     > > Thanks,
>     >>         >     >
>     >>         >     > > Acee
>     >>         >     >
>     >>         >     > >
>     >>         >     >
>     >>         >     > >
>     >>         >     >
>     >>         >     > >     Lada
>     >>         >     >
>     >>         >     > >
>     >>         >     >
>     >>         >     > >     >
>     >>         >     >
>     >>         >     > >     > Also note that I use derived-from-or-self instead of equality
> for the
>     >>         >     >
>     >>         >     > >     > identity.
>     >>         >     >
>     >>         >     > >     >
>     >>         >     >
>     >>         >     > >     >
>     >>         >     >
>     >>         >     > >     > /martin
>     >>         >     >
>     >>         >     > >     >
>     >>         >     >
>     >>         >     > >     >
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > > Regards,
>     >>         >     >
>     >>         >     > >     > > Reshad.
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > >   augment "/rt:routing/rt:control-plane-protocols/"
>     >>         >     >
>     >>         >     > >     > >         + "rt:control-plane-protocol" {
>     >>         >     >
>     >>         >     > >     > >      when "rt:type = ‘msdp’"  {
>     >>         >     >
>     >>         >     > >     > >       description
>     >>         >     >
>     >>         >     > >     > >         "….”;
>     >>         >     >
>     >>         >     > >     > >     }
>     >>         >     >
>     >>         >     > >     > >     description "….";
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > >     container msdp {
>     >>         >     >
>     >>         >     > >     > >       when "../rt:name = ‘msdp-protocol’"  {
>     >>         >     >
>     >>         >     > >     > >         description
>     >>         >     >
>     >>         >     > >     > >           "….";
>     >>         >     >
>     >>         >     > >     > >       }
>     >>         >     >
>     >>         >     > >     > >       description "MSDP top level container.";
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > > From: "Reshad Rahman (rrahman)" <rrahman@xxxxxxxxx>
>     >>         >     >
>     >>         >     > >     > > Date: Monday, February 5, 2018 at 6:25 PM
>     >>         >     >
>     >>         >     > >     > > To: Xufeng Liu <Xufeng_Liu@xxxxxxxxx>,
>     >>         > "zhang.zheng@xxxxxxxxxx"
>     >>         >     >
>     >>         >     > >     > > <zhang.zheng@xxxxxxxxxx>
>     >>         >     >
>     >>         >     > >     > > Cc: "anish.ietf@xxxxxxxxx" <anish.ietf@xxxxxxxxx>,
> "Mahesh
>     >>         > Sivakumar
>     >>         >     >
>     >>         >     > >     > > (masivaku)" <masivaku@xxxxxxxxx>,
> "guofeng@xxxxxxxxxx"
>     >>         >     >
>     >>         >     > >     > > <guofeng@xxxxxxxxxx>,
> "pete.mcallister@xxxxxxxxxxxxxx"
>     >>         >     >
>     >>         >     > >     > > <pete.mcallister@xxxxxxxxxxxxxx>,
> "liuyisong@xxxxxxxxxx"
>     >>         >     >
>     >>         >     > >     > > <liuyisong@xxxxxxxxxx>, "xu.benchong@xxxxxxxxxx"
>     >>         >     >
>     >>         >     > >     > > <xu.benchong@xxxxxxxxxx>, "tanmoy.kundu@alcatel-
>     >>         > lucent.com"
>     >>         >     >
>     >>         >     > >     > > <tanmoy.kundu@xxxxxxxxxxxxxxxxxx>,
>     >>         > "zzhang_ietf@xxxxxxxxxxx"
>     >>         >     >
>     >>         >     > >     > > <zzhang_ietf@xxxxxxxxxxx>, "Acee Lindem (acee)"
>     >>         > <acee@xxxxxxxxx>
>     >>         >     >
>     >>         >     > >     > > Subject: Re: Hi all, about the modification of MSDP YANG
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > > Hi Sandy and Xufeng,
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > > I understand that you want only 1 MSDP instance but I
> don’t think
>     >>         >     > that
>     >>         >     >
>     >>         >     > >     > > justifies /rt:routing/rt:control-plane-protocols. If we do
> that we
>     >>         >     >
>     >>         >     > >     > > will end up with all single-instance protocols under
>     >>         >     >
>     >>         >     > >     > > /rt:routing/rt:control-plane-protocols and all the multi-
> instance
>     >>         >     > ones
>     >>         >     >
>     >>         >     > >     > > under
>     >>         >     >
>     >>         >     > >     > > /rt:routing/rt:control-plane-protocols/rt:control-plane-
> protocol.
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > > I am not sure what’s the best way to enforce single-
> instance, I can
>     >>         >     >
>     >>         >     > >     > > check with the other YDs on this topic. One way it can be
> done is
>     >>         > as
>     >>         >     >
>     >>         >     > >     > > follows (I’ve added the when statement in bold to
> existing BFD
>     >>         >     > model),
>     >>         >     >
>     >>         >     > >     > > it enforces that the protocol name is ‘bfdv1’. So multiple
>     >>         > instances
>     >>         >     >
>     >>         >     > >     > > with rt:type=bfd-types:bfdv1 could be created, but only
> one of
>     >>         > these
>     >>         >     >
>     >>         >     > >     > > instances can have the bfd container. This is probably not
> the
>     >>         > best
>     >>         >     >
>     >>         >     > >     > > way but the point is that IMO protocols have to go under
>     >>         >     >
>     >>         >     > >     > > /rt:routing/rt:control-plane-protocols/rt:control-plane-
> protocol.
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > > Regards,
>     >>         >     >
>     >>         >     > >     > > Reshad.
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > >   augment "/rt:routing/rt:control-plane-protocols/"
>     >>         >     >
>     >>         >     > >     > >         + "rt:control-plane-protocol" {
>     >>         >     >
>     >>         >     > >     > >      when "rt:type = 'bfd-types:bfdv1'"  {
>     >>         >     >
>     >>         >     > >     > >       description
>     >>         >     >
>     >>         >     > >     > >         "This augmentation is only valid for a control-plane
>     >>         >     > protocol
>     >>         >     >
>     >>         >     > >     > >          instance of BFD (type 'bfdv1').";
>     >>         >     >
>     >>         >     > >     > >     }
>     >>         >     >
>     >>         >     > >     > >     description "BFD augmentation.";
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > >     container bfd {
>     >>         >     >
>     >>         >     > >     > >       when "../rt:name = 'bfdv1'"  {
>     >>         >     >
>     >>         >     > >     > >         description
>     >>         >     >
>     >>         >     > >     > >           "This augmentation is only valid for a control-plane
>     >>         >     > protocol
>     >>         >     >
>     >>         >     > >     > >            instance of BFD (type 'bfdv1').";
>     >>         >     >
>     >>         >     > >     > >       }
>     >>         >     >
>     >>         >     > >     > >       description "BFD top level container.";
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > > From: Xufeng Liu <Xufeng_Liu@xxxxxxxxx>
>     >>         >     >
>     >>         >     > >     > > Date: Monday, February 5, 2018 at 9:38 AM
>     >>         >     >
>     >>         >     > >     > > To: "zhang.zheng@xxxxxxxxxx"
> <zhang.zheng@xxxxxxxxxx>
>     >>         >     >
>     >>         >     > >     > > Cc: "Reshad Rahman (rrahman)" <rrahman@xxxxxxxxx>,
>     >>         >     >
>     >>         >     > >     > > "anish.ietf@xxxxxxxxx" <anish.ietf@xxxxxxxxx>,
> "Mahesh
>     >>         > Sivakumar
>     >>         >     >
>     >>         >     > >     > > (masivaku)" <masivaku@xxxxxxxxx>,
> "guofeng@xxxxxxxxxx"
>     >>         >     >
>     >>         >     > >     > > <guofeng@xxxxxxxxxx>,
> "pete.mcallister@xxxxxxxxxxxxxx"
>     >>         >     >
>     >>         >     > >     > > <pete.mcallister@xxxxxxxxxxxxxx>,
> "liuyisong@xxxxxxxxxx"
>     >>         >     >
>     >>         >     > >     > > <liuyisong@xxxxxxxxxx>, "xu.benchong@xxxxxxxxxx"
>     >>         >     >
>     >>         >     > >     > > <xu.benchong@xxxxxxxxxx>, "tanmoy.kundu@alcatel-
>     >>         > lucent.com"
>     >>         >     >
>     >>         >     > >     > > <tanmoy.kundu@xxxxxxxxxxxxxxxxxx>,
>     >>         > "zzhang_ietf@xxxxxxxxxxx"
>     >>         >     >
>     >>         >     > >     > > <zzhang_ietf@xxxxxxxxxxx>
>     >>         >     >
>     >>         >     > >     > > Subject: RE: Hi all, about the modification of MSDP YANG
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > > Hi Sandy,
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > > Thanks for the updates.
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > > In RFC8022bis, the rt:type is defined under
>     >>         >     >
>     >>         >     > >     > > /rt:routing/rt:control-plane-protocols/rt:control-plane-
> protocol.
>     >>         > If
>     >>         >     >
>     >>         >     > >     > > we augment /rt:routing/rt:control-plane-protocols, the
> “when”
>     >>         >     >
>     >>         >     > >     > > statement will not be valid, because it cannot find the
> rt:type. I
>     >>         >     >
>     >>         >     > >     > > don’t think that we need the “when” statement. The
> container
>     >>         > with
>     >>         >     >
>     >>         >     > >     > > “presence” will serve the purpose of the identity. We can
> simply
>     >>         >     > take
>     >>         >     >
>     >>         >     > >     > > out the “when” statement and the definition of the MSDP
> identity.
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > > Thanks,
>     >>         >     >
>     >>         >     > >     > > - Xufeng
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > > From: zhang.zheng@xxxxxxxxxx
> [mailto:zhang.zheng@xxxxxxxxxx]
>     >>         >     >
>     >>         >     > >     > > Sent: Monday, February 5, 2018 3:36 AM
>     >>         >     >
>     >>         >     > >     > > To: Xufeng Liu <Xufeng_Liu@xxxxxxxxx>
>     >>         >     >
>     >>         >     > >     > > Cc: rrahman@xxxxxxxxx; anish.ietf@xxxxxxxxx;
>     >>         > masivaku@xxxxxxxxx;
>     >>         >     >
>     >>         >     > >     > > guofeng@xxxxxxxxxx;
> pete.mcallister@xxxxxxxxxxxxxx;
>     >>         >     >
>     >>         >     > >     > > liuyisong@xxxxxxxxxx; xu.benchong@xxxxxxxxxx;
>     >>         >     >
>     >>         >     > >     > > tanmoy.kundu@xxxxxxxxxxxxxxxxxx;
> zzhang_ietf@xxxxxxxxxxx
>     >>         >     >
>     >>         >     > >     > > Subject: RE: Hi all, about the modification of MSDP YANG
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > > Hi Xufeng and Reshad,
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > > I am sorry for forgetting the point. I updated the YANG
> model.
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > > If no one has comments on it I'd like to submit the new
> version. :-)
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > > Thanks,
>     >>         >     >
>     >>         >     > >     > >
>     >>         >     >
>     >>         >     > >     > > Sandy
>     >>         >     >
>     >>         >     > >     > > 原始邮件
>     >>         >     >
>     >>         >     > >     > > 发件人：
>     >>         > <Xufeng_Liu@xxxxxxxxx<mailto:Xufeng_Liu@xxxxxxxxx>>;
>     >>    

================================

 

On Mon, Aug 13, 2018 at 10:34 AM Jan Lindblad <janl@xxxxxxxxxx> wrote:

Reviewer: Jan Lindblad
Review result: On the Right Track

This is my YANG-doctor review of draft-ietf-pim-igmp-mld-yang-07. In the
spring, I did an early review of the -02 version.

Most of the comments from the earlier review are still valid. In some ways the
document has progressed since -02, in many it has not, and in a few it has
deteriorated. In my judgement, the document is not ready for last call. Many
fundamentally important questions are still unresolved. Here are my review
comments in rough falling order of importance.

#1 Improper augment of /rt:routing/rt:control-plane-protocols

Quoted from section 3.1:
   This model augments the core routing data model "ietf-routing"
   specified in [RFC8349].  The IGMP model augments "/rt:routing/
   rt:control-plane-protocols" as opposed to augmenting "/rt:routing/
   rt:control-plane-protocols/rt:control-plane-protocol", as the latter
   would allow multiple protocol instances, while the IGMP protocol is
   designed to be enabled or disabled as a single protocol instance on
   a network instance or a logical network element.

The description above, and the actual augment statements in the YANG module
violate the principles described in RFC 8349, the ietf-routing.yang module it
augments. In RFC 8349, section 5.3.  Control-Plane Protocol, the proper way of
augmenting the routing module is described. The fact that this is a singleton
protocol instance doesn't change this. Section 5.3 describes singleton cases as
well.

#2 Incorrect vendor refinement model

Quoted from section 2.2:
   For the same reason, wide constant ranges (for example, timer
   maximum and minimum) will be used in the model.  It is expected that
   vendors will augment the model with any specific restrictions that
   might be required. Vendors may also extend the features list with
   proprietary extensions.

This is not acceptable. The principle suggested does not foster
interoperability and useful standards. It is also not possible to do what the
paragraph suggests in YANG. This was pointed out in the -02 review, and a
suggestion was given there on how to address the problem.

#3 Top level structures not optional

Quoted from section 2.3:
   The current document contains IGMP and MLD as separate schema
   branches in the structure. The reason for this is to make it easier
   for implementations which may optionally choose to support specific
   address families. And the names of objects may be different between
   the IPv4 (IGMP) and IPv6 (MLD) address families.

This problem was also pointed out in the -02 review. The author suggests that
implementing igmp and/or mld is optional. This is not reflected in the YANG
module, however. As currently modeled, both are currently mandatory to
implement. If-feature is used liberally in the module, and could be used here
as well.

#4 Unclear meaning of optional leaves

Quoted from section 3.1:
   Where fields are not genuinely essential to protocol operation, they
   are marked as optional. Some fields will be essential but have a
   default specified, so that they need not be configured explicitly.

In fact, in the current version of the module, every leaf is optional (except
keys, which cannot be optional). It is good to see the addition of defaults in
many cases, but many unclear cases remain. E.g. leaf /igmp/global/enable is of
type boolean. I understand what true and false implies for this leaf. But what
does it mean if it is not set at all? Either add a default or describe the
meaning in the description. Similarly, if the leaf version is not set on an
igmp or mld interface, or on the interface-global level, what does that mean?
Add default. require-router-alert? explicit-tracking? exclude-lite? Many of
these are used in NP-containers inheriting all the from the root, which makes
the use of mandatory highly discouraged in the current form. If the RFC 8349
augmentation principles are followed, the concern around mandatory falls, and
some leafs with no sensible default could be marked mandatory instead.

#5 All optional state

All state data is optional, which means a conforming server could very well
decide not to implement it. E.g. discontinuity-time is optional. Should a
manager count on this being available? A situation where every leaf is optional
is as nice and flexible for server implementors as it is frustrating and
complicated for manager implementors to consume. A YANG model is an API
contract and should consider the needs of both sides. The way this has been
designed reveals that no representation for the consumer side of this model has
been involved in the design. I would suggest thinking through what is the most
essential state data for a manager, and make some leafs mandatory.

#6 Abundant copy-paste

There is abundant repetition in the YANG module. leaf version is defined 2
times for igmp with identical definitions, and two more for mld with identical
definitions. leaf enable is defined once for the interface global-level, and
with identical definition on the interface local level. leaf
last-member-query-interval, query-interval and half a dozen other leaves are
defined twice with identical definitions.

#7 Leaf interface in the rpc clear*groups on line 1124, 1094 has type string.
Should be a leafref? Describe what values are valid. #8 Leaf group-policy,
source-policy on line 486, 527, 624, 689: type string. Should be leafref?
Describe what values are valid. #9 Leaf group on line 705, 1101, 1131: Is any
ipv4/6 address ok, or only a multicast address? Model accordingly.

 

PIM Working Group                                                X. Liu
Internet-Draft                                                    Volta
Intended Status: Standard Track                                  F. Guo
Expires: April 15, 2019                                          Huawei
                                                           M. Sivakumar
                                                                Juniper
                                                          P. McAllister
                                                    Metaswitch Networks
                                                               A. Peter
                                                             Individual
                                                       October 15, 2018


    A YANG data model for Internet Group Management Protocol (IGMP) and
                    Multicast Listener Discovery (MLD)
                      draft-ietf-pim-igmp-mld-yang-08


Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six
   months and may be updated, replaced, or obsoleted by other documents
   at any time.  It is inappropriate to use Internet-Drafts as
   reference material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html

   This Internet-Draft will expire on April 15, 2019.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors. All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document. Please review these documents



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   carefully, as they describe your rights and restrictions with
   respect to this document. Code Components extracted from this
   document must include Simplified BSD License text as described in
   Section 4.e of the Trust Legal Provisions and are provided without
   warranty as described in the Simplified BSD License.

Abstract

   This document defines a YANG data model that can be used to
   configure and manage Internet Group Management Protocol (IGMP) and
   Multicast Listener Discovery (MLD) devices.

Table of Contents


   1. Introduction ................................................ 2
      1.1. Terminology ............................................ 3
      1.2. Tree Diagrams .......................................... 3
      1.3. Prefixes in Data Node Names............................. 3
   2. Design of Data model......................................... 4
      2.1. Scope of model ......................................... 4
      2.2. Optional capabilities................................... 4
      2.3. Position of address family in hierarchy................. 5
   3. Module Structure ............................................ 5
      3.1. IGMP Configuration and Operational state................ 5
      3.2. MLD Configuration and Operational State................. 7
      3.3. IGMP and MLD RPC........................................ 9
   4. IGMP and MLD YANG Modules................................... 10
   5. Security Considerations..................................... 33
   6. IANA Considerations ........................................ 35
   7. Acknowledgments ............................................ 35
   8. Contributing Authors........................................ 36
   9. References ................................................. 36
      9.1. Normative References................................... 36
      9.2. Informative References................................. 38

1. Introduction

   YANG [RFC6020] [RFC7950] is a data definition language that was
   introduced to model the configuration and running state of a device
   managed using network management protocols such as NETCONF [RFC6241]
   or RESTCONF [RFC8040]. YANG is now also being used as a component of
   wider management interfaces, such as CLIs.

   This document defines a YANG data model that can be used to
   configure and manage Internet Group Management Protocol (IGMP) and
   Multicast Listener Discovery (MLD) devices. This model will support
   the core IGMP and MLD protocols, as well as many other features



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   mentioned in separate IGMP and MLD RFCs. Non-core features are
   defined as optional in the provided data model.

1.1. Terminology

   The terminology for describing YANG data models is found in
   [RFC6020] [RFC7950].

   The following abbreviations are used in this document and the
   defined model:

   IGMP:

      Internet Group Management Protocol [RFC3376].

   MLD:

      Multicast Listener Discovery [RFC3810].

1.2. Tree Diagrams

   Tree diagrams used in this document follow the notation defined in
   [RFC8340].

1.3. Prefixes in Data Node Names

   In this document, names of data nodes, actions, and other data model
   objects are often used without a prefix, as long as it is clear from
   the context in which YANG module each name is defined.  Otherwise,
   names are prefixed using the standard prefix associated with the

   +-----------+--------------------------+---------------------+

   | Prefix    | YANG module              | Reference           |

   +-----------+--------------------------+---------------------+

   | yang      | ietf-yang-types          | [RFC6991]           |

   | inet      | ietf-inet-types          | [RFC6991]           |

   | if        | ietf-interfaces          | [RFC8343]           |

   | ip        | ietf-ip                  | [RFC8344]           |

   | rt        | ietf-routing             | [RFC8349]           |

   | rt-types  | ietf-routing-types       | [RFC8294]           |



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   | acl       | ietf-access-control-list | [I-D.ietf-acl-yang] |

   +-----------+--------------------------+---------------------+



             Table 1: Prefixes and Corresponding YANG Modules

2. Design of Data model

2.1. Scope of model

   The model covers IGMPv1 [RFC1112], IGMPv2 [RFC2236], IGMPv3
   [RFC3376] and MLDv1 [RFC2710], MLDv2 [RFC3810].

   The configuration of IGMP and MLD features, and the operational
   state fields and RPC definitions are not all included in this
   document of the data model. This model can be extended, though the
   structure of what has been written may be taken as representative of
   the structure of the whole model.

   This model does not cover other IGMP and MLD related protocols such
   as IGMP/MLD Proxy [RFC4605] or IGMP/MLD Snooping [RFC4541] etc.,
   these will be specified in separate documents.

2.2. Optional capabilities

   This model is designed to represent the capabilities of IGMP and MLD
   devices with various specifications, including some with basic
   subsets of the IGMP and MLD protocols.  The main design goals of
   this document are that any major now-existing implementation may be
   said to support the basic model, and that the configuration of all
   implementations meeting the specification is easy to express through
   some combination of the features in the basic model and simple
   vendor augmentations.

   There is also value in widely-supported features being standardized,
   to save work for individual vendors, and so that mapping between
   different vendors' configuration is not needlessly complicated.
   Therefore these modules declare a number of features representing
   capabilities that not all deployed devices support.

   The extensive use of feature declarations should also substantially
   simplify the capability negotiation process for a vendor's IGMP and
   MLD implementations.

   On the other hand, operational state parameters are not so widely
   designated as features, as there are many cases where the defaulting
   of an operational state parameter would not cause any harm to the


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   system, and it is much more likely that an implementation without
   native support for a piece of operational state would be able to
   derive a suitable value for a state variable that is not natively
   supported.

2.3. Position of address family in hierarchy

   The current document contains IGMP and MLD as separate schema
   branches in the structure. The reason for this is to make it easier
   for implementations which may optionally choose to support specific
   address families. And the names of objects may be different between
   the IPv4 (IGMP) and IPv6 (MLD) address families.

3. Module Structure

3.1. IGMP Configuration and Operational state

   The IGMP YANG model conforms to the Network Management Datastore
   Architecture (NMDA) [RFC8342]. The operational state data is
   combined with the associated configuration data in the same
   hierarchy [I-D.ietf-netmod-rfc6087bis]. The IGMP module defines in a
   three-level hierarchy structure as listed below:

       Global level: IGMP configuration and operational state attributes
   for the entire routing system.

       Interface-global: Only including configuration data nodes that
   IGMP configuration attributes are applicable to all the interfaces
   whose interface-level corresponding attributes are not existing,
   with same attributes' value for these interfaces.

       Interface-level: IGMP configuration and operational state
   attributes specific to the given interface.

   Where fields are not genuinely essential to protocol operation, they
   are marked as optional. Some fields will be essential but have a
   default specified, so that they need not be configured explicitly.

   This model augments the core routing data model "ietf-routing"
   specified in [RFC8349].  The IGMP model augments "/rt:routing/
   rt:control-plane-protocols" as opposed to augmenting "/rt:routing/
   rt:control-plane-protocols/rt:control-plane-protocol", as the latter
   would allow multiple protocol instances, while the IGMP protocol is
   designed to be enabled or disabled as a single protocol instance on
   a network instance or a logical network element.

     augment /rt:routing/rt:control-plane-protocols:
       +--rw igmp {feature-igmp}?
          +--rw global


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          |  +--rw enable?          boolean {global-admin-enable}?
          |  +--rw max-entries?     uint32 {global-max-entries}?
          |  +--rw max-groups?      uint32 {global-max-groups}?
          |  +--ro entries-count?   uint32
          |  +--ro groups-count?    uint32
          |  +--ro statistics
          |     +--ro discontinuity-time?   yang:date-and-time
          |     +--ro error
          |     |  +--ro total?       yang:counter64
          |     |  +--ro query?       yang:counter64
          |     |  +--ro report?      yang:counter64
          |     |  +--ro leave?       yang:counter64
          |     |  +--ro checksum?    yang:counter64
          |     |  +--ro too-short?   yang:counter64
          |     +--ro received
          |     |  +--ro total?    yang:counter64
          |     |  +--ro query?    yang:counter64
          |     |  +--ro report?   yang:counter64
          |     |  +--ro leave?    yang:counter64
          |     +--ro sent
          |        +--ro total?    yang:counter64
          |        +--ro query?    yang:counter64
          |        +--ro report?   yang:counter64
          |        +--ro leave?    yang:counter64
          +--rw interfaces
             +--rw last-member-query-interval?   uint16
             +--rw query-interval?               uint16
             +--rw query-max-response-time?      uint16
             +--rw require-router-alert?         boolean {intf-require-router-alert}?
             +--rw robustness-variable?          uint8
             +--rw version?                      uint8
             +--rw max-groups-per-interface?     uint32 {intf-max-groups}?
             +--rw interface* [interface-name]
                +--rw interface-name                if:interface-ref
                +--rw last-member-query-interval?   uint16
                +--rw query-interval?               uint16
                +--rw query-max-response-time?      uint16
                +--rw require-router-alert?         boolean {intf-require-router-alert}?
                +--rw robustness-variable?          uint8
                +--rw version?                      uint8
                +--rw enable?                       boolean {intf-admin-enable}?
                +--rw group-policy?                 -> /acl:acls/acl/name
                +--rw immediate-leave?              empty {intf-immediate-leave}?
                +--rw max-groups?                   uint32 {intf-max-groups}?
                +--rw max-group-sources?            uint32 {intf-max-group-sources}?
                +--rw source-policy?                -> /acl:acls/acl/name {intf-source-policy}?
                +--rw verify-source-subnet?         empty {intf-verify-source-subnet}?
                +--rw explicit-tracking?            empty {intf-explicit-tracking}?
                +--rw exclude-lite?                 empty {intf-exclude-lite}?


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                +--rw join-group*                   rt-types:ipv4-multicast-group-address {intf-join-group}?
                +--rw ssm-map* [ssm-map-source-addr ssm-map-group-policy] {intf-ssm-map}?
                |  +--rw ssm-map-source-addr     ssm-map-ipv4-addr-type
                |  +--rw ssm-map-group-policy    string
                +--rw static-group* [group-addr source-addr] {intf-static-group}?
                |  +--rw group-addr     rt-types:ipv4-multicast-group-address
                |  +--rw source-addr    rt-types:ipv4-multicast-source-address
                +--ro oper-status                   enumeration
                +--ro querier                       inet:ipv4-address
                +--ro joined-group*                 rt-types:ipv4-multicast-group-address {intf-join-group}?
                +--ro group* [group-address]
                   +--ro group-address    rt-types:ipv4-multicast-group-address
                   +--ro expire           uint32
                   +--ro filter-mode      enumeration
                   +--ro up-time          uint32
                   +--ro last-reporter?   inet:ipv4-address
                   +--ro source* [source-address]
                      +--ro source-address    inet:ipv4-address
                      +--ro expire            uint32
                      +--ro up-time           uint32
                      +--ro host-count?       uint32 {intf-explicit-tracking}?
                      +--ro last-reporter?    inet:ipv4-address
                      +--ro host* [host-address] {intf-explicit-tracking}?
                         +--ro host-address        inet:ipv4-address
                         +--ro host-filter-mode    enumeration


3.2. MLD Configuration and Operational State

   The MLD YANG model uses the same structure as IGMP YANG model. The
   MLD module also defines in a three-level hierarchy structure as
   listed below:

     augment /rt:routing/rt:control-plane-protocols:
       +--rw mld {feature-mld}?
          +--rw global
          |  +--rw enable?          boolean {global-admin-enable}?
          |  +--rw max-entries?     uint32 {global-max-entries}?
          |  +--rw max-groups?      uint32 {global-max-groups}?
          |  +--ro entries-count?   uint32
          |  +--ro groups-count?    uint32
          |  +--ro statistics
          |     +--ro discontinuity-time?   yang:date-and-time
          |     +--ro error
          |     |  +--ro total?       yang:counter64
          |     |  +--ro query?       yang:counter64
          |     |  +--ro report?      yang:counter64
          |     |  +--ro leave?       yang:counter64
          |     |  +--ro checksum?    yang:counter64


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          |     |  +--ro too-short?   yang:counter64
          |     +--ro received
          |     |  +--ro total?    yang:counter64
          |     |  +--ro query?    yang:counter64
          |     |  +--ro report?   yang:counter64
          |     |  +--ro leave?    yang:counter64
          |     +--ro sent
          |        +--ro total?    yang:counter64
          |        +--ro query?    yang:counter64
          |        +--ro report?   yang:counter64
          |        +--ro leave?    yang:counter64
          +--rw interfaces
             +--rw last-member-query-interval?   uint16
             +--rw query-interval?               uint16
             +--rw query-max-response-time?      uint16
             +--rw require-router-alert?         boolean {intf-require-router-alert}?
             +--rw robustness-variable?          uint8
             +--rw version?                      uint8
             +--rw max-groups-per-interface?     uint32 {intf-max-groups}?
             +--rw interface* [interface-name]
                +--rw interface-name                if:interface-ref
                +--rw last-member-query-interval?   uint16
                +--rw query-interval?               uint16
                +--rw query-max-response-time?      uint16
                +--rw require-router-alert?         boolean {intf-require-router-alert}?
                +--rw robustness-variable?          uint8
                +--rw version?                      uint8
                +--rw enable?                       boolean {intf-admin-enable}?
                +--rw group-policy?                 -> /acl:acls/acl/name
                +--rw immediate-leave?              empty {intf-immediate-leave}?
                +--rw max-groups?                   uint32 {intf-max-groups}?
                +--rw max-group-sources?            uint32 {intf-max-group-sources}?
                +--rw source-policy?                -> /acl:acls/acl/name {intf-source-policy}?
                +--rw verify-source-subnet?         empty {intf-verify-source-subnet}?
                +--rw explicit-tracking?            empty {intf-explicit-tracking}?
                +--rw exclude-lite?                 empty {intf-exclude-lite}?
                +--rw join-group*                   rt-types:ipv6-multicast-group-address {intf-join-group}?
                +--rw ssm-map* [ssm-map-source-addr ssm-map-group-policy] {intf-ssm-map}?
                |  +--rw ssm-map-source-addr     ssm-map-ipv6-addr-type
                |  +--rw ssm-map-group-policy    string
                +--rw static-group* [group-addr source-addr] {intf-static-group}?
                |  +--rw group-addr     rt-types:ipv6-multicast-group-address
                |  +--rw source-addr    rt-types:ipv6-multicast-source-address
                +--ro oper-status                   enumeration
                +--ro querier                       inet:ipv6-address
                +--ro joined-group*                 rt-types:ipv6-multicast-group-address {intf-join-group}?
                +--ro group* [group-address]
                   +--ro group-address    rt-types:ipv6-multicast-group-address
                   +--ro expire           uint32


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                   +--ro filter-mode      enumeration
                   +--ro up-time          uint32
                   +--ro last-reporter?   inet:ipv6-address
                   +--ro source* [source-address]
                      +--ro source-address    inet:ipv6-address
                      +--ro expire            uint32
                      +--ro up-time           uint32
                      +--ro host-count?       uint32 {intf-explicit-tracking}?
                      +--ro last-reporter?    inet:ipv6-address
                      +--ro host* [host-address] {intf-explicit-tracking}?
                         +--ro host-address        inet:ipv6-address
                         +--ro host-filter-mode    enumeration


3.3. IGMP and MLD RPC

   IGMP and MLD RPC clears the specified IGMP and MLD group membership.

     rpcs:

       +---x clear-igmp-groups {rpc-clear-groups}?

       |  +---w input

       |     +---w interface-name?   -> /rt:routing/control-plane-
   protocols/igmp-mld:igmp/interfaces/interface/interface-name
   {feature-igmp}?

       |     +---w group-address?    rt-types:ipv4-multicast-group-
   address

       |     +---w source-address?   rt-types:ipv4-multicast-source-
   address

       +---x clear-mld-groups {rpc-clear-groups}?

          +---w input

             +---w interface-name?   -> /rt:routing/control-plane-
   protocols/igmp-mld:mld/interfaces/interface/interface-name {feature-
   mld}?

             +---w group-addrss?     rt-types:ipv6-multicast-group-
   address

             +---w source-address?   rt-types:ipv6-multicast-source-
   address




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4. IGMP and MLD YANG Modules

   <CODE BEGINS> file "ietf-igmp-mld@xxxxxxxxxxxxxxx"
   module ietf-igmp-mld {
      yang-version 1.1;
      namespace "urn:ietf:params:xml:ns:yang:ietf-igmp-mld";
      // replace with IANA namespace when assigned
      prefix igmp-mld;

      import ietf-inet-types {
        prefix "inet";
      }

      import ietf-yang-types {
        prefix "yang";
      }

      import ietf-routing-types {
        prefix "rt-types";
      }

      import ietf-access-control-list {
        prefix "acl";
      }

      import ietf-routing {
        prefix "rt";
      }

      import ietf-interfaces {
        prefix "if";
      }

      import ietf-ip {
        prefix ip;
      }

      organization
        "IETF PIM Working Group";

      contact
        "WG Web:   <http://tools.ietf.org/wg/pim/>
         WG List:  <mailto:pim@xxxxxxxx>

         WG Chair: Stig Venaas
                   <mailto:stig@xxxxxxxxxx>

         WG Chair: Mike McBride
                   <mailto:mmcbride7@xxxxxxxxx>


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         Editor:   Xufeng Liu
                   <mailto:xufeng.liu.ietf@xxxxxxxxx>

         Editor:   Feng Guo
                   <mailto:guofeng@xxxxxxxxxx>

         Editor:   Mahesh Sivakumar
                   <mailto:sivakumar.mahesh@xxxxxxxxx>

         Editor:   Pete McAllister
                   <mailto:pete.mcallister@xxxxxxxxxxxxxx>

         Editor:   Anish Peter
                   <mailto:anish.ietf@xxxxxxxxx>";

      description
        "The module defines a collection of YANG definitions common for
        IGMP and MLD.";

      revision 2018-09-15 {
        description
          "Updated yang data model for default value, address type and
           repeated leaf definition.";
        reference
          "RFC XXXX: A YANG Data Model for IGMP and MLD";
      }
      revision 2018-06-21 {
        description
          "Updated yang data model for parameter range and description.";
        reference
          "RFC XXXX: A YANG Data Model for IGMP and MLD";
      }
      revision 2017-10-20 {
        description
          "Updated yang data model for adding explicit-tracking and
           lightweight IGMPv3 and MLDv2 function.";
        reference
          "RFC XXXX: A YANG Data Model for IGMP and MLD";
      }
      revision 2017-09-19 {
        description
          "Updated yang data model for NMDA version and errata.";
        reference
          "RFC XXXX: A YANG Data Model for IGMP and MLD";
      }

      /*
       * Features


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       */
      feature feature-igmp {
        description
          "Support IGMP protocol for IPv4 group membership record.";
      }
      feature feature-mld {
        description
          "Support MLD protocol for IPv6 group membership record.";
      }
      feature global-admin-enable {
        description
          "Support global configuration to enable or disable protocol.";
      }

      feature global-interface-config {
        description
          "Support global configuration applied for all interfaces.";
      }

      feature global-max-entries {
        description
          "Support configuration of global max-entries.";
      }

      feature global-max-groups {
        description
          "Support configuration of global max-groups.";
      }

      feature intf-admin-enable {
        description
          "Support configuration of interface administrative enabling.";
      }

      feature intf-immediate-leave {
        description
          "Support configuration of interface immediate-leave.";
      }

      feature intf-join-group {
        description
          "Support configuration of interface join-group.";
      }

      feature intf-max-groups {
        description
          "Support configuration of interface max-groups.";
      }



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      feature intf-max-group-sources {
        description
          "Support configuration of interface max-group-sources.";
      }

      feature intf-require-router-alert {
        description
          "Support configuration of interface require-router-alert.";
      }

      feature intf-source-policy {
        description
          "Support configuration of interface source policy.";
      }

      feature intf-ssm-map {
        description
          "Support configuration of interface ssm-map.";
      }

      feature intf-static-group {
        description
          "Support configuration of interface static-group.";
      }

      feature intf-verify-source-subnet {
        description
          "Support configuration of interface verify-source-subnet.";
      }

      feature intf-explicit-tracking {
        description
          "Support configuration of interface explicit-tracking hosts.";
      }

      feature intf-exclude-lite {
        description
          "Support configuration of interface exclude-lite.";
      }

      feature per-interface-config {
        description
          "Support per interface configuration.";
      }

      feature rpc-clear-groups {
        description
          "Support rpc's to clear groups.";
      }


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      /*
       * Typedefs
       */
      typedef ssm-map-ipv4-addr-type {
        type union {
          type enumeration {
            enum 'policy' {
              description
              "Source address is specified in SSM map policy.";
            }
          }
          type inet:ipv4-address;
        }
        description
          "Multicast source IP address type for SSM map.";
      } // source-ipv4-addr-type

      typedef ssm-map-ipv6-addr-type {
        type union {
          type enumeration {
            enum 'policy' {
              description
              "Source address is specified in SSM map policy.";
            }
          }
          type inet:ipv6-address;
        }
        description
          "Multicast source IP address type for SSM map.";
      } // source-ipv6-addr-type

      /*
       * Identities
       */

      /*
       * Groupings
       */
      grouping global-config-attributes {
        description "Global IGMP and MLD configuration.";

        leaf enable {
          if-feature global-admin-enable;
          type boolean;
          default false;
          description
            "true to enable IGMP or MLD in the routing instance;
             false to disable IGMP or MLD in the routing instance.";


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        }

        leaf max-entries {
          if-feature global-max-entries;
          type uint32;
          description
            "The maximum number of entries in IGMP or MLD.";
        }
        leaf max-groups {
          if-feature global-max-groups;
          type uint32;
          description
            "The maximum number of groups that IGMP
             or MLD can join.";
        }
      } // global-config-attributes

      grouping global-state-attributes {

        description "Global IGMP and MLD state attributes.";

        leaf entries-count {
          type uint32;
          config false;
          description
            "The number of entries in IGMP or MLD.";
        }
        leaf groups-count {
          type uint32;
          config false;
          description
            "The number of groups that IGMP or MLD can join.";
        }

        container statistics {
          config false;
          description "Global statistics.";

          leaf discontinuity-time {
            type yang:date-and-time;
            description
              "The time on the most recent occasion at which any one
              or more of the statistic counters suffered a
              discontinuity. If no such discontinuities have occurred
              since the last re-initialization of the local
              management subsystem, then this node contains the time
              the local management subsystem re-initialized itself.";
          }



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          container error {
            description "Statistics of errors.";
            uses global-statistics-error;
          }

          container received {
            description "Statistics of received messages.";
            uses global-statistics-sent-received;
          }
          container sent {
            description "Statistics of sent messages.";
            uses global-statistics-sent-received;
          }
        } // statistics
      } // global-state-attributes

      grouping global-statistics-error {
        description
          "A grouping defining statistics attributes for errors.";
        uses global-statistics-sent-received;
        leaf checksum {
          type yang:counter64;
          description
            "The number of checksum errors.";
        }
        leaf too-short {
          type yang:counter64;
          description
            "The number of messages that are too short.";
        }
      } // global-statistics-error

      grouping global-statistics-sent-received {
        description
          "A grouping defining statistics attributes.";
        leaf total {
          type yang:counter64;
          description
            "The number of total messages.";
        }
        leaf query {
          type yang:counter64;
          description
            "The number of query messages.";
        }
        leaf report {
          type yang:counter64;
          description
            "The number of report messages.";


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        }
        leaf leave {
          type yang:counter64;
          description
            "The number of leave messages.";
        }
      } // global-statistics-sent-received

      grouping interface-global-config-attributes {
        description
          "Configuration attributes applied to the interface global level
           whose per interface attributes are not existing.";

        leaf max-groups-per-interface {
          if-feature intf-max-groups;
          type uint32;
          description
            "The maximum number of groups that IGMP or MLD can join.";
        }
      } //interface-global-config-attributes

      grouping interface-common-config-attributes {
        description
          "Configuration attributes applied to both the interface global
           level and interface level.";

        leaf last-member-query-interval {
          type uint16 {
            range "1..1023";
          }
          units seconds;
          default 1;
          description
            "Last Member Query Interval, which may be tuned to modify the
             leave latency of the network.";
           reference "RFC3376. Sec. 8.8.";
        }

        leaf query-interval {
          type uint16 {
            range "1..31744";
          }
          units seconds;
          default 125;
          description
            "The Query Interval is the interval between General Queries
             sent by the Querier.In RFC3376, Querier's Query Interval(QQI) is
             represented from the Querier's Query Interval Code in query
             message as follows:


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             If QQIC < 128, QQI = QQIC
             If QQIC >= 128, QQIC represents a floating-point value as follows:
              0 1 2 3 4 5 6 7
             +-+-+-+-+-+-+-+-+
             |1| exp | mant  |
             +-+-+-+-+-+-+-+-+
             QQI = (mant | 0x10) << (exp + 3)
             The maximum value of QQI is 31744.";
          reference "RFC3376. Sec. 4.1.7, 8.2, 8.14.2.";
        }

        leaf query-max-response-time {
          type uint16 {
            range "1..1023";
          }
          units seconds;
          default 10;
          description
            "Query maximum response time specifies the maximum time
             allowed before sending a responding report.";
          reference "RFC3376. Sec. 4.1.1, 8.3, 8.14.3.";
        }

        leaf require-router-alert {
          if-feature intf-require-router-alert;
          type boolean;
          default false;
          description
            "Protocol packets should contain router alert IP option.";
        }

        leaf robustness-variable {
          type uint8 {
            range "1..7";
          }
          default 2;
          description
            "Querier's Robustness Variable allows tuning for the expected
             packet loss on a network.";
          reference "RFC3376. Sec. 4.1.6, 8.1, 8.14.1.";
        }

      } // interface-common-config-attributes

      grouping interface-common-config-attributes-igmp {
        description
          "Configuration attributes applied to both the interface global
           level and interface level for IGMP.";
        uses interface-common-config-attributes;


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        leaf version {
          type uint8 {
            range "1..3";
          }
          default 2;
          description "IGMP version.";
          reference "RFC1112, RFC2236, RFC3376.";
        }
      }

      grouping interface-common-config-attributes-mld {
        description
          "Configuration attributes applied to both the interface global
           level and interface level for MLD.";
        uses interface-common-config-attributes;
        leaf version {
          type uint8 {
            range "1..2";
          }
          default 2;
          description "MLD version.";
          reference "RFC2710, RFC3810.";
        }
      }

      grouping interfaces-config-attributes-igmp {
        description
          "Configuration attributes applied to the interface global
           level for IGMP.";
        uses interface-common-config-attributes-igmp;
        uses interface-global-config-attributes;
      }

      grouping interfaces-config-attributes-mld {
        description
          "Configuration attributes applied to the interface global
           level for MLD.";
        uses interface-common-config-attributes-mld;
        uses interface-global-config-attributes;
      }

      grouping interface-specific-config-attributes {
        description
          "Per interface configuration attributes for both IGMP and MLD
           whose are not existing in interface global level.";

        leaf enable {
          if-feature intf-admin-enable;
          type boolean;


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          default false;
          description
            "true to enable IGMP or MLD on the interface;
             false to disable IGMP or MLD on the interface.";
        }
        leaf group-policy {
          type leafref {
            path "/acl:acls/acl:acl/acl:name";
          }
          description
            "Name of the access policy used to filter IGMP or MLD
             membership.A device can restrict the length
             and value of this name, possibly space and special
             characters are not allowed.";
        }
        leaf immediate-leave {
          if-feature intf-immediate-leave;
          type empty;
          description
            "If present, IGMP or MLD perform an immediate leave upon
             receiving an IGMPv2 or MLDv1 leave message.
             If the router is IGMP-enabled or MLD-enabled, it sends an
             IGMP or MLD last member query with a last member query
             response time. However, the router does not wait for
             the response time before it prunes off the group.";
        }
        leaf max-groups {
          if-feature intf-max-groups;
          type uint32;
          description
            "The maximum number of groups that IGMP ro MLD can join.";
        }
        leaf max-group-sources {
          if-feature intf-max-group-sources;
          type uint32;
          description
            "The maximum number of group sources.";
        }

        leaf source-policy {
          if-feature intf-source-policy;
          type leafref {
            path "/acl:acls/acl:acl/acl:name";
          }
          description
            "Name of the access policy used to filter sources.
             A device can restrict the length
             and value of this name, possibly space and special
             characters are not allowed.";


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        }
        leaf verify-source-subnet {
          if-feature intf-verify-source-subnet;
          type empty;
          description
            "If present, the interface accepts packets with matching
             source IP subnet only.";
        }
        leaf explicit-tracking {
          if-feature intf-explicit-tracking;
          type empty;
          description
            "If present, IGMP/MLD-based explicit membership tracking function
             for multicast routers and IGMP/MLD proxy devices
             supporting IGMPv3/MLDv2. The explicit membership tracking
             function contributes to saving network resources and
             shortening leave latency.";
        }
        leaf exclude-lite {
          if-feature intf-exclude-lite;
          type empty;
          description
            "If present, lightweight IGMPv3 and MLDv2 protocols will run on the
             which simplify the standard versions of IGMPv3 and MLDv2.";
          reference "RFC5790";
        }

      } // interface-specific-config-attributes

      grouping interface-config-attributes-igmp {
        description
          "Per interface configuration attributes for IGMP.";

        uses interface-common-config-attributes-igmp;
        uses interface-specific-config-attributes;

        leaf-list join-group {
          if-feature intf-join-group;
          type rt-types:ipv4-multicast-group-address;
          description
            "The router joins this multicast group on the interface.";
        }

        list ssm-map {
          if-feature intf-ssm-map;
          key "ssm-map-source-addr ssm-map-group-policy";
          description "The policy for (*,G) mapping to (S,G).";
          leaf ssm-map-source-addr {
            type ssm-map-ipv4-addr-type;


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            description
              "Multicast source IPv4 address.";
          }
          leaf ssm-map-group-policy {
            type string;
            description
              "Name of the policy used to define ssm-map rules.
               A device can restrict the length
               and value of this name, possibly space and special
               characters are not allowed. ";
          }
        }

        list static-group {
          if-feature intf-static-group;
          key "group-addr source-addr";
          description
            "A static multicast route, (*,G) or (S,G).";

          leaf group-addr {
            type rt-types:ipv4-multicast-group-address;
            description
              "Multicast group IPv4 address.";
          }
          leaf source-addr {
            type rt-types:ipv4-multicast-source-address;
            description
              "Multicast source IPv4 address.";
          }
        }
      } // interface-config-attributes-igmp



      grouping interface-config-attributes-mld {
        description
          "Per interface configuration attributes for MLD.";

        uses interface-common-config-attributes-mld;
        uses interface-specific-config-attributes;

        leaf-list join-group {
          if-feature intf-join-group;
          type rt-types:ipv6-multicast-group-address;
          description
            "The router joins this multicast group on the interface.";
        }

        list ssm-map {


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          if-feature intf-ssm-map;
          key "ssm-map-source-addr ssm-map-group-policy";
          description "The policy for (*,G) mapping to (S,G).";
          leaf ssm-map-source-addr {
            type ssm-map-ipv6-addr-type;
            description
              "Multicast source IPv6 address.";
          }
          leaf ssm-map-group-policy {
            type string;
            description
              "Name of the policy used to define ssm-map rules.
               A device can restrict the length
               and value of this name, possibly space and special
               characters are not allowed.";
          }
        }

        list static-group {
          if-feature intf-static-group;
          key "group-addr source-addr";
          description
            "A static multicast route, (*,G) or (S,G).";

          leaf group-addr {
            type rt-types:ipv6-multicast-group-address;
            description
              "Multicast group IPv6 address.";
          }
          leaf source-addr {
            type rt-types:ipv6-multicast-source-address;
            description
              "Multicast source IPv6 address.";
          }
        }
      } // interface-config-attributes-mld

      grouping interface-state-attributes-igmp-mld {
        description
          "Per interface state attributes for both IGMP and MLD.";

        leaf oper-status {
          type enumeration {
            enum up {
              description
              "Ready to pass packets.";
            }
            enum down {
              description


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              "The interface does not pass any packets.";
            }
          }
          config false;
          mandatory true;
          description
            "Interface up or down state for IGMP or MLD protocol";
        }
      } // interface-config-attributes-igmp-mld

      grouping interface-state-attributes-igmp {

        description
          "Per interface state attributes for IGMP.";

        uses interface-state-attributes-igmp-mld;

        leaf querier {
          type inet:ipv4-address;
          config false;
          mandatory true;
          description "The querier address in the subnet";
        }
        leaf-list joined-group {
          if-feature intf-join-group;
          type rt-types:ipv4-multicast-group-address;
          config false;
          description
            "The routers that joined this multicast group.";
        }

        list group {
          key "group-address";
          config false;
          description
            "Multicast group membership information
            that joined on the interface.";

          leaf group-address {
            type rt-types:ipv4-multicast-group-address;
            description
              "Multicast group address.";
          }
          uses interface-state-group-attributes-igmp-mld;

          leaf last-reporter {
            type inet:ipv4-address;
            description
              "The last host address which has sent the


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               report to join the multicast group.";
          }
          list source {
            key "source-address";
            description
              "List of multicast source information
               of the multicast group.";

            leaf source-address {
              type inet:ipv4-address;
              description
                "Multicast source address in group record.";
            }
            uses interface-state-source-attributes-igmp-mld;
            leaf last-reporter {
              type inet:ipv4-address;
              description
                "The last host address which has sent the
                 report to join the multicast source and group.";
            }
            list host {
              if-feature intf-explicit-tracking;
              key "host-address";
              description
                "List of multicast membership hosts
                 of the specific multicast source-group.";

              leaf host-address {
                type inet:ipv4-address;
                description
                  "Multicast membership host address.";
              }
              uses interface-state-host-attributes-igmp-mld;
            }// list host
          } // list source
        } // list group
      } // interface-state-attributes-igmp

      grouping interface-state-attributes-mld {

        description
          "Per interface state attributes for MLD.";

        uses interface-state-attributes-igmp-mld;

        leaf querier {
          type inet:ipv6-address;
          config false;
          mandatory true;


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          description
            "The querier address in the subnet.";
        }
        leaf-list joined-group {
          if-feature intf-join-group;
          type rt-types:ipv6-multicast-group-address;
          config false;
          description
            "The routers that joined this multicast group.";
        }

        list group {
          key "group-address";
          config false;
          description
            "Multicast group membership information
            that joined on the interface.";

          leaf group-address {
            type rt-types:ipv6-multicast-group-address;
            description
              "Multicast group address.";
          }
          uses interface-state-group-attributes-igmp-mld;
          leaf last-reporter {
            type inet:ipv6-address;
            description
              "The last host address which has sent the
               report to join the multicast group.";
          }
          list source {
            key "source-address";
            description
              "List of multicast source information
               of the multicast group.";

            leaf source-address {
              type inet:ipv6-address;
              description
                "Multicast source address in group record";
            }
            uses interface-state-source-attributes-igmp-mld;
            leaf last-reporter {
              type inet:ipv6-address;
              description
                "The last host address which has sent the
                 report to join the multicast source and group.";
            }
            list host {


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              if-feature intf-explicit-tracking;
              key "host-address";
              description
                "List of multicast membership hosts
                 of the specific multicast source-group.";

              leaf host-address {
                type inet:ipv6-address;
                description
                  "Multicast membership host address.";
              }
              uses interface-state-host-attributes-igmp-mld;
            }// list host
          } // list source
        } // list group
      } // interface-state-attributes-mld

      grouping interface-state-group-attributes-igmp-mld {
        description
          "Per interface state attributes for both IGMP and MLD
           groups.";

        leaf expire {
          type uint32;
          units seconds;
          mandatory true;
          description
            "The time left before multicast group state expires.";
        }
        leaf filter-mode {
          type enumeration {
            enum "include" {
              description
                "In include mode, reception of packets sent
                 to the specified multicast address is requested
                 only from those IP source addresses listed in the
                 source-list parameter";
            }
            enum "exclude" {
              description
                "In exclude mode, reception of packets sent
                 to the given multicast address is requested
                 from all IP source addresses except those
                 listed in the source-list parameter.";
            }
          }
          mandatory true;
          description
            "Filter mode for a multicast group,


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             may be either include or exclude.";
        }
        leaf up-time {
          type uint32;
          units seconds;
          mandatory true;
          description
            "The elapsed time since the device created multicast group record.";
        }
      } // interface-state-group-attributes-igmp-mld

      grouping interface-state-source-attributes-igmp-mld {
        description
          "Per interface state attributes for both IGMP and MLD
           source-group records.";

        leaf expire {
          type uint32;
          units seconds;
          mandatory true;
          description
            "The time left before multicast source-group state expires.";
        }
        leaf up-time {
          type uint32;
          units seconds;
          mandatory true;
          description
            "The elapsed time since the device created multicast
             source-group record.";
        }
        leaf host-count {
          if-feature intf-explicit-tracking;
          type uint32;
          description
            "The number of host addresses.";
        }
      } // interface-state-source-attributes-igmp-mld

      grouping interface-state-host-attributes-igmp-mld {
        description
          "Per interface state attributes for both IGMP and MLD
           hosts of source-group records.";

        leaf host-filter-mode {
          type enumeration {
            enum "include" {
              description
                "In include mode";


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            }
            enum "exclude" {
              description
                "In exclude mode.";
            }
          }
          mandatory true;
          description
            "Filter mode for a multicast membership
             host may be either include or exclude.";
        }
      }// interface-state-host-attributes-igmp-mld

      /*
       * Configuration and Operational state data nodes (NMDA version)
       */
      augment "/rt:routing/rt:control-plane-protocols"
      {
        description
          "IGMP augmentation to routing control plane protocol
           configuration and state.";

        container igmp {
          if-feature feature-igmp;
          description
            "IGMP configuration and operational state data.";

          container global {
            description
              "Global attributes.";
            uses global-config-attributes;
            uses global-state-attributes;
          }

          container interfaces {
            description
              "Containing a list of interfaces.";

            uses interfaces-config-attributes-igmp {
              if-feature global-interface-config;
            }

            list interface {
              key "interface-name";
              description
                "List of IGMP interfaces.";
              leaf interface-name {
                type if:interface-ref;
                must "/if:interfaces/if:interface[if:name = current()]/"


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                   + "ip:ipv4" {
                  description
                    "The interface must have IPv4 enabled.";
                }
                description
                  "Reference to an entry in the global interface list.";
              }
              uses interface-config-attributes-igmp {
                if-feature per-interface-config;
              }
              uses interface-state-attributes-igmp;
            } // interface
          } // interfaces
        } // igmp
      }//augment

      augment "/rt:routing/rt:control-plane-protocols"
      {
        description
          "MLD augmentation to routing control plane protocol
           configuration and state.";

        container mld {
          if-feature feature-mld;
          description
            "MLD configuration and operational state data.";

          container global {
            description
              "Global attributes.";
            uses global-config-attributes;
            uses global-state-attributes;
          }

          container interfaces {
            description
              "Containing a list of interfaces.";

            uses interfaces-config-attributes-mld {
              if-feature global-interface-config;
            }

            list interface {
              key "interface-name";
              description
                "List of MLD interfaces.";
              leaf interface-name {
                type if:interface-ref;
                must "/if:interfaces/if:interface[if:name = current()]/"


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                   + "ip:ipv6" {
                  description
                    "The interface must have IPv6 enabled.";
                }
                description
                  "Reference to an entry in the global interface list.";
              }
              uses interface-config-attributes-mld {
                if-feature per-interface-config;
              }
              uses interface-state-attributes-mld;
            } // interface
          } // interfaces
        } // mld
      } // augment

      /*
       * RPCs
       */
      rpc clear-igmp-groups {
        if-feature rpc-clear-groups;
        description
          "Clears the specified IGMP cache entries.";

        input {
          leaf interface-name {
            if-feature feature-igmp;
            type leafref {
              path "/rt:routing/rt:control-plane-protocols/"
                + "igmp-mld:igmp/igmp-mld:interfaces/"
                + "igmp-mld:interface/igmp-mld:interface-name";
            }
            description
              "Name of the IGMP interface.
               If it is not specified, groups from all interfaces are
               cleared.";
          }
          leaf group-address {
            type rt-types:ipv4-multicast-group-address;
            description
              "Multicast group IPv4 address.
               If it is not specified, all IGMP group entries are
               cleared.";
          }
          leaf source-address {
            type rt-types:ipv4-multicast-source-address;
            description
              "Multicast source IPv4 address.
               If it is not specified, all IGMP source-group entries are


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               cleared.";
          }
        }
      } // rpc clear-igmp-groups

      rpc clear-mld-groups {
        if-feature rpc-clear-groups;
        description
          "Clears the specified MLD cache entires.";

        input {
          leaf interface-name {
            if-feature feature-mld;
            type leafref {
              path "/rt:routing/rt:control-plane-protocols/"
                + "igmp-mld:mld/igmp-mld:interfaces/"
                + "igmp-mld:interface/igmp-mld:interface-name";
            }
            description
              "Name of the MLD interface.
               If it is not specified, groups from all interfaces are
               cleared.";
          }
          leaf group-addrss {
            type rt-types:ipv6-multicast-group-address;
            description
              "Multicast group IPv6 address.
               If it is not specified, all MLD group entries are
               cleared.";
          }
          leaf source-address {
            type rt-types:ipv6-multicast-source-address;
            description
              "Multicast source IPv6 address.
               If it is not specified, all MLD source-group entries are
               cleared.";
          }
        }
      } // rpc clear-mld-groups

      /*
       * Notifications
       */
    }
   <CODE ENDS>






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5. Security Considerations

   The YANG module specified in this document defines a schema for data
   that is designed to be accessed via network management protocols
   such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF
   layer is the secure transport layer, and the mandatory-to-implement
   secure transport is Secure Shell (SSH) [RFC6242]. The lowest
   RESTCONF layer is HTTPS, and the mandatory-to-implement secure
   transport is TLS [RFC5246].

   The NETCONF access control model [RFC6536] provides the means to
   restrict access for particular NETCONF or RESTCONF users to a
   preconfigured subset of all available NETCONF or RESTCONF protocol
   operations and content.

   There are a number of data nodes defined in this YANG module that
   are writable/creatable/deletable (i.e., config true, which is the
   default). These data nodes may be considered sensitive or vulnerable
   in some network environments. Write operations (e.g., edit-config)
   to these data nodes without proper protection can have a negative
   effect on network operations. These are the subtrees and data nodes
   and their sensitivity/vulnerability:

   igmp:global

     This subtree specifies the configuration for the IGMP attributes
     at the global level on a device.  Modifying the configuration can
     cause IGMP membership deleted or reconstructed on all the
     interfaces of a device.

   igmp:interfaces

     This subtree specifies the configuration for the IGMP attributes
     at all of the interfaces level on a device.  Modifying the
     configuration can cause IGMP membership deleted or reconstructed
     on all the interfaces of a device.

   igmp:interfaces/interface

     This subtree specifies the configuration for the IGMP attributes
     at the interface level on a device.  Modifying the configuration
     can cause IGMP membership deleted or reconstructed on a specific
     interface of a device.

   These subtrees are all under

   /rt:routing/rt:control-plane protocols/igmp:

   mld:global


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     This subtree specifies the configuration for the MLD attributes at
     the global level on a device.  Modifying the configuration can
     cause MLD membership deleted or reconstructed on all the
     interfaces of a device.

   mld:interfaces

     This subtree specifies the configuration for the MLD attributes at
     all of the interfaces level on a device.  Modifying the
     configuration can cause MLD membership deleted or reconstructed on
     all the interfaces of a device.

   mld:interfaces/interface

     This subtree specifies the configuration for the MLD attributes at
     the interface level on a device.  Modifying the configuration can
     cause MLD membership deleted or reconstructed on a specific
     interface of a device.

   These subtrees are all under

   /rt:routing/rt:control-plane-protocols/mld:

   Unauthorized access to any data node of these subtrees can adversely
   affect the membership records of multicast routing subsystem on the
   local device.  This may lead to network malfunctions, delivery of
   packets to inappropriate destinations, and other problems.

   Some of the readable data nodes in this YANG module may be
   considered sensitive or vulnerable in some network environments. It
   is thus important to control read access (e.g., via get, get-config,
   or notification) to these data nodes. These are the subtrees and
   data nodes and their sensitivity/vulnerability:

   /rt:routing/rt:control-plane-protocols/igmp

   /rt:routing/rt:control-plane-protocols/mld

    Unauthorized access to any data node of the above subtree can
    disclose the operational state information of IGMP or MLD on this
    device.

   Some of the RPC operations in this YANG module may be considered
   sensitive or vulnerable in some network environments. It is thus
   important to control access to these operations. These are the
   operations and their sensitivity/vulnerability:

   clear-igmp-groups



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   clear-mld-groups

   Unauthorized access to any of the above RPC operations can delete
   the IGMP or MLD membership records on this device.

6. IANA Considerations

   RFC Ed.: In this section, replace all occurrences of 'XXXX' with the
   actual RFC number (and remove this note).

    This document registers the following namespace URIs in the IETF XML
    registry [RFC3688]:

   --------------------------------------------------------------------

   URI: urn:ietf:params:xml:ns:yang:ietf-igmp-mld

   Registrant Contact: The IESG.

   XML: N/A, the requested URI is an XML namespace.

   --------------------------------------------------------------------

   This document registers the following YANG modules in the YANG Module
   Names registry [RFC7950]:

   --------------------------------------------------------------------

   name:         ietf-igmp-mld

   namespace:    urn:ietf:params:xml:ns:yang:ietf-igmp-mld

   prefix:       igmp-mld

   reference:    RFC XXXX

   --------------------------------------------------------------------

7. Acknowledgments

    The authors would like to thank Steve Baillargeon, Hu Fangwei,
    Robert Kebler, Tanmoy Kundu, and Stig Venaas for their valuable
    contributions.








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8. Contributing Authors

   Yisong Liu
   Huawei Technologies
   Huawei Bldg., No.156 Beiqing Rd.
   Beijing  100095
   China

   Email: liuyisong@xxxxxxxxxx


9. References

9.1. Normative References

   [RFC1112] Deering, S., "Host extensions for IP multicasting", STD 5,
             RFC 1112, August 1989.

   [RFC2236] Fenner, W., "Internet Group Management Protocol, Version
             2", RFC 2236, November 1997.

   [RFC2710] Deering, S., Fenner, W., and B. Haberman, "Multicast
             Listener Discovery (MLD) for IPv6", RFC 2710,  October
             1999.

   [RFC3376] Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A.
             Thyagarajan, "Internet Group Management Protocol, Version
             3", RFC 3376,  October 2002.

   [RFC3688] Mealling, M., "The IETF XML Registry", RFC 3688, January
             2004

   [RFC3810] Vida, R. and L. Costa, "Multicast Listener Discovery
             Version 2 (MLDv2) for IPv6", RFC 3810, June 2004.

   [RFC4541] M. Christensen, K. Kimball and F. Solensky,
             "Considerations for Internet Group Management Protocol
             (IGMP) and Multicast Listener Discovery (MLD) Snooping
             Switches", RFC 4541, May 2006.

   [RFC4605] B. Fenner, H. He, B. Haberman, and H. Sandick, "Internet
             Group Management Protocol (IGMP) / Multicast Listener
             Discovery (MLD)-Based Multicast Forwarding ("IGMP/MLD
             Proxying")", RFC 4605, August 2006.

   [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
             (TLS) Protocol Version 1.2", RFC 5246, August 2008




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   [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
             the Network Configuration Protocol (NETCONF)", RFC 6020,
              October 2010

   [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
             and A. Bierman, Ed., "Network Configuration Protocol
             (NETCONF)", RFC 6241, June 2011

   [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
             Shell (SSH)", RFC 6242, June 2011

   [RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration
             Protocol (NETCONF) Access Control Model", RFC 6536, April
             2012

   [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
             RFC 6991, July 2013

   [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
             RFC 7950, August 2016

   [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
             Protocol", RFC 8040, January 2017

   [RFC8294] Liu, X., Qu, Y., Lindem, A., Hopps, C., and L. Berger,
             "Common YANG Data Types for the Routing Area", RFC 8294,
             December 2017

   [RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
             and R. Wilton, "Network Management Datastore Architecture
             (NMDA)", RFC 8342, April 2018

   [RFC8343] Bjorklund, M., "A YANG Data Model for Interface
             Management", RFC 8343, April 2018

   [RFC8344] M. Bjorklund, "A YANG Data Model for IP Management",
             RFC8344, April 2018

   [RFC8349] Lhotka, L., Lindem, A., and Y. Qu, "A YANG Data Model for
             Routing Management (NMDA Version)", RFC 8349, April 2018

   [I-D.ietf-acl-yang] M. Jethanandani, L. Huang, S. Agarwal and D.
             Blair, "Network Access Control List (ACL) YANG Data
             Model", draft-ietf-netmod-acl-model-19(work in progress),
             April 2018






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9.2. Informative References

   [RFC5790] H. Liu, W. Cao and H. Asaeda, "Lightweight Internet Group
             Management Protocol Version 3 (IGMPv3) and Multicast
             Listener Discovery Version 2 (MLDv2) Protocols", RFC 5790,
             February 2010

   [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
             BCP 215, RFC 8340, April 2018

   [I-D.ietf-netmod-rfc6087bis] Bierman, A., "Guidelines for Authors
             and Reviewers of YANG Data Model Documents", draft-ietf-
             netmod-rfc6087bis-20(work in progress), April 2018





































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   Authors' Addresses

   Xufeng Liu
   Volta Networks




   EMail: xufeng.liu.ietf@xxxxxxxxx


   Feng Guo
   Huawei Technologies
   Huawei Bldg., No.156 Beiqing Rd.
   Beijing  100095
   China

   Email: guofeng@xxxxxxxxxx


   Mahesh Sivakumar
   Juniper Networks
   1133 Innovation Way
   Sunnyvale, California
   USA

   Email: sivakumar.mahesh@xxxxxxxxx


   Pete McAllister
   Metaswitch Networks
   100 Church Street
   Enfield  EN2 6BQ
   UK

   EMail: pete.mcallister@xxxxxxxxxxxxxx


   Anish Peter
   Individual




   EMail: anish.ietf@xxxxxxxxx






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