Re: [MIB-DOCTORS] Benoit Claise's Discuss on draft-ietf-manet-nhdp-mib-14: (with DISCUSS and COMMENT) (UNCLASSIFIED)

[Thomas Nadeau <[e-mail]>]

Yes, that would be very helpful! 8)

--Tom


From: Ulrich Herberg <[e-mail]<mailto:[e-mail]>>
To: "Cole, Robert G CIV USARMY CERDEC (US)" <[e-mail]<mailto:[e-mail]>>
Cc: Thomas Nadeau <[e-mail]<mailto:[e-mail]>>, "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>, "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>, "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>
Subject: Re: Benoit Claise's Discuss on draft-ietf-manet-nhdp-mib-14: (with DISCUSS and COMMENT) (UNCLASSIFIED)

Hi,

regarding the list of interfaces, in RFC6130 (NHDP), *all* interfaces are listed in the Local Interface Set, not just the MANET interfaces. The reason is that these addresses are also advertised in HELLO messages (e.g., so that these addresses can be used by routing protocols). If we only list MANET interfaces in the NHDP-MIB module, this would not reflect the state in NHDP. Maybe we should add a comment in the description that only MANET interfaces are listed in the MIB module and others in the IfTable?

Best
Ulrich

On Wed, Jun 13, 2012 at 2:20 PM, Cole, Robert G CIV USARMY CERDEC (US) <[e-mail]<mailto:[e-mail]>> wrote:
Tom,  thx.  Will do. Bob

----- Original Message -----
From: Thomas Nadeau [mailto:[e-mail]<mailto:[e-mail]>]
Sent: Wednesday, June 13, 2012 08:15 PM
To: Cole, Robert G CIV USARMY CERDEC (US); 'MIB Doctors (E-mail)' <[e-mail]<mailto:[e-mail]>>
Cc: Ulrich Herberg <[e-mail]<mailto:[e-mail]>>; Benoit Claise <[e-mail]<mailto:[e-mail]>>; [e-mail]<mailto:[e-mail]> <[e-mail]<mailto:[e-mail]>>
Subject: Re: Benoit Claise's Discuss on draft-ietf-manet-nhdp-mib-14: (with DISCUSS and COMMENT) (UNCLASSIFIED)



On 6/13/12 4:02 PM, "Cole, Robert G CIV USARMY CERDEC (US)"
<[e-mail]<mailto:[e-mail]>> wrote:

>Classification: UNCLASSIFIED
>Caveats: NONE
>
>Tom,
>
>
>-you wrote-
>        I appreciate the reference but my points from earlier still apply.
>In the reference, I believe operationally you avoid entries that do not
>have
>the correct ifType for the Ipv4InterfaceEntry.  Remember that if that were
>not the case, then what you get is a direct one-to-one mapping of IPv4
>interfaces attributes for EVERY IfTable entry.  This is a bad idea given
>that there are a wide array of devices that have a small set of their
>interfaces possessing IPv4 characteristics.
>
>RGC> I do not see in reading through the reference RFC 4293, how this
>behavior is identified.  I agree with you that this is desirable.  I just
>do
>not see the mechanism that informs the implementer to scope the ifType.

TOM: The reference doesn't explicitly say this, but that is how I believe
its implemented.

>
>        In your MIB you are effectively doing this.  If you really wanted
>that you should use AUGMENTS, but that doesn't seem like what you want.
>The
>simple way to correct this situation is to define an ifType for NHDP
>interfaces and explicitly exclude non-NHDP interfaces from being returned.
> This effectively "extends" - or more appropriately - "selectively
>extends"
>the IfTable entries.
>
>RGC> You are right; it is this later case and behavior we want to achieve.
>Where do I define an ifType for NHDP interfaces?  Also more generally,
>should I be defining an ifType for MANET interfaces?

       You do this in an IANA section. Take a look at how we did this in
RFC3811/12/13. It is pretty straight-forward. You can also see how to
scope its use tightly to avoid scale issues. I think you would want an
ifType for MANET - I was mistaken earlier when I said NHDP.

       --Tom



>
>Thanks, Bob
>
>
>        --Tom
>
>
>>
>>Thanks,
>>Bob Cole
>>
>>
>>-----Original Message-----
>>From: Benoit Claise [mailto:[e-mail]<mailto:[e-mail]>]
>>Sent: Thursday, June 07, 2012 11:05 AM
>>To: [e-mail]<mailto:[e-mail]>
>>Cc: 'The IESG'; [e-mail]<mailto:[e-mail]>;
>>[e-mail]<mailto:[e-mail]>
>>Subject: Re: Benoit Claise's Discuss on draft-ietf-manet-nhdp-mib-14:
>>(with
>>DISCUSS and COMMENT)
>>
>>Hi Adrian,
>>
>>
>>       Hi Benoit,
>>
>>       I'm going to be a bit sniffy here :-)
>>
>>
>>               - There is a clear DISCUSS coming from the MIB-doctor
>review. Please
>>               address it.
>>
>>
>>       Sorry, what is your Discuss?
>>
>>My Discuss is simply: improve the MIB module according to the MIB
>>doctor Looking at the long list of open issues, copied for the IESG
>>convenience below, I wrote "clear DISCUSS"
>>
>>
>>       General Comments
>>       ----------------
>>
>>
>>        1.  I did not re-compile the MIB as I am assuming Bert's
>>comments from compilation were sufficient.  These comments are IN
>>ADDITION to Bert's so please make fixes required from his comments too.
>>
>>       2. Please go through the objects in the module and look for uses
>>of DISPLAY-STRING and UNITS where possible. There are numerous cases
>>where it should have been used but wasn't. I did not point out every
>>one, just the first one.
>>
>>       3. In general, you have not explicitly described what happens to
>>rows in the tables where read-create objects exist. You must describe
>>these behaviors. I have noted the first instance of this, but please
>>check all tables.
>>
>>       4. The use of DisplayString in the MIB is quite prevalent.
>>RFC4181 is very clear in stating that:
>>
>>          Note 2.  DisplayString does not support internationalized text.
>It
>>                   MUST NOT be used for objects that are required to hold
>>                   internationalized text (which is always the case if
>>the
>>                   object is intended for use by humans [RFC2277]).
>Designers
>>                   SHOULD consider using SnmpAdminString, Utf8String, or
>>                   LongUtf8String for such objects.
>>
>>
>>
>>       5. You need a DEFVAL for *every* read-create object. I have
>>noted the first case, but there are LOTS of these in the module that
>>need to be fixed.
>>
>>       6. There is some confusion about your ifTable interaction. You
>>seem to want an EXTENDS relationship, but your modeling is one of
>>AUGMENTS. That is, the index text describes two types of interfaces
>>(without a proper ifType BTW), where you allow for the modeling of
>>non-manet interfaces. What I think you want to do is have this
>>relationship:
>>
>>       ifEntry NhdpInterfaceEntry
>>       1, ifType=mols
>>       2, ifType=mpls
>>       3, ifType=manet    ---------> 3
>>       4, ifType = manet  --------->       4
>>       5, ifType = mpls
>>
>>       That is, you do not have entries in the NhdpInterfaceEntry table
>>for ifIndex-es 1, 2 and 5.
>>
>>
>>       7. I think it is customary to include the full reference
>>description in the REFERENCE clause. For example:
>>
>>                  "RFC 2863 - The Interfaces Group MIB, McCloghrie, K.,
>>                    and F. Kastenholtz, June 2000"
>>
>>
>>       There are a number of these in the document, but I have only
>>noted the first one. Please go through the document and make these
>>corrections, and please do it consistently.
>>
>>       8. When you use InetAddress, you are constraining it to 4 or 16.
>>This is unusual. It is typical to just use the TC as-is.
>>
>>       9.  I have found a number of tables that match this guidance.
>>The easiest thing to do is create a StorageType object in each table
>>and define its semantics.  I have only noted one case of this, but
>>there are a number of them.
>>
>>       There either MUST be one columnar object with a SYNTAX value of
>>              StorageType [RFC2579] and a MAX-ACCESS value of
>>read-create,
>or
>>              else the row object (table entry) DESCRIPTION clause MUST
>specify
>>              what happens to dynamically-created rows after an agent
>restart.
>>
>>
>>
>>
>>
>>       10. In the notifications section, there is ambiguous terminology
>like
>>"significant number"; you need to define what you expect this means.   In
>>fact, there is a lot of examples for defining explicit MIB variables
>>like nhdpNbrStateChangeThreshold that explicitly define this. This will
>>help aid interoperability.  All of the notifications suffer from this
>>deficiency.
>>
>>
>>       11. The notifications emitted here seem to be potentially of a
>>high volume given that manet applications can include massive numbers
>>of "mobile"
>>devices.
>>You really should include some limiting/throttling parameters as
>>explicit MIB configuration values.  I know that you have defined this
>>in some of the description clauses, but this is not easily
>>interoperable, especially if implementations really need to use smaller
>>values.  Also, the way things are written, it is possible for
>>implementations to experience DoS attack on the device because it is
>>forced to emit so many notifications that it overwhelms the CPU. The
>>"bad packets" notification is a great example.
>>
>>       12. The  nhdpIfState notification is potentially dangerous given
>>how the IfTable relationship is currently defined above to be
>>essentially a 1:1 match with the IfEntry.  Imagine having to issue
>>notifications constantly for IF state changes for every interface in
>>the normal IF-MIB and then here?
>>Also,
>>what value does this notification add above/beyond the normal IfUp/Down
>>notification if you define an ifType=manet as I suggested above?
>>
>>       13. The  nhdpPacketSrcAddr  notification has no limits or
>throttling.
>>What if
>>%100 of the packets sent to the device match this criteria? Do you
>>issue a notification for every one?
>>
>>
>>
>>
>>
>>       Could you please capture your Discuss in the data tracker so
>>that it can be resolved in discussion with you.
>>
>>Ok.
>>
>>
>>
>>
>>
>>               - While reading through the document, I've been really
>waiting for an
>>               applicability statement section.
>>
>>
>>       So, I think you are asking "Why would any application that is
>>not using telnet and a CLI or directly attached to the node want to
>>know any details about the topology learnt by the node?"
>>
>>Not really, basically, I'm asking a very simple question: how do you
>>plan on managing an ad-hoc network?
>>
>>
>>
>>
>>       I might ask you what is the point of the IF-MIB? Why would any
>>management application ever want to learn about the behavior of a
>>network node using a standardised protocol?
>>
>>I don't understand this.
>>
>>
>>
>>
>>
>>               A sentence [RFC6130] such as "if router A is able to
>exchange packets
>>               with router B, and router B is able to exchange packets
>>with
>router C,
>>               this does not guarantee that router A and router C can
>exchange packets
>>               directly" got me thinking about the management and
>operational aspects.
>>               How do you plan on using this MIB module, taking into
>>account that you're
>>               dealing with an ad-hoc network?
>>
>>
>>       I am not sure whether you asking
>>       - How will a TCP-based application work in a MANET?
>>
>>Yes.
>>
>>
>>
>>       or
>>       - What information might you learn from a MANET node
>>          that implements NHDP?
>>
>>       NHDP discovers neighbors. Neighbor relationships are not
>>necessarily symmetric. They are hard to predict because they depend on
>>physical placement of the nodes (and other conditions that affect
>>wireless transmissions).
>>Reading the information gathered using NHDP allows an external
>>application to generate  map of the topology. Reading statistics about
>>the performance of the protocol allows an application to assess whether
>>there is a misbehaving implementation and also whether the reported
>>topology is likely to be accurate.
>>
>>       This all seems rather "obvious". I guess a statement like this
>>could be added to the document. I hope that this would mean that
>>*every* MIB module that goes for publication from now on will be
>>required to add similar explanation of why a MIB module is relevant.
>>
>>
>>               Note that the write-up mentions: "This document shepherd
>>is
>not aware of
>>               existing implementations of this MIB although several
>implementers have
>>               indicated interest in the work."
>>               So the potential implementers should have some views on
>>the
>following
>>               questions.
>>
>>               I'm really after 3 different parts in the applicability
>statement (or
>>               call it use cases if you want to): configuration
>>management,
>monitoring,
>>               and notification. And I have questions such as:
>>               * one static NMS or each MANET router configures/monitors
>his (newly
>>               attached) neighbor(s)?
>>
>>
>>       I think the question you are asking is about write-access. I
>>think it is obvious from the module that the node can update the
>>information that is reported by an application reading the module. So
>>the question is why is so much write-access needed to so many objects
>>in the module? That is something the authors/WG need to answer.
>>
>>Coming back to my basic question: how do you plan on managing an ad-hoc
>>network?
>>Do you want to have one static NMS monitoring the entire network, or do
>>you want to have every router only monitoring his neighbors (*).
>>
>>
>>
>>
>>
>>               * where are the notifications sent to?
>>
>>
>>       Hmmm? Why is this question any different for this module
>>compared with any other module? Who consumes Notifications from other
>>modules?
>>
>>In the case of (*)
>>
>>
>>
>>
>>
>>               * Do you expect all MANET routers to always have
>>connectivity to a static
>>               NMS?
>>
>>
>>       Why ever not? It is a routed IP network. If there is a
>>management station present, it can connect. If the network becomes
>>partitioned, well, this is the same problem as in any other network.
>>
>>You know, I started to find a couple of my points addressed in
>>http://www.herberg.name/downloads/pubs/CNSM_10.pdf
>><blockedhttp://www.herberg.name/downloads/pubs/CNSM_10.pdf<http://www.herberg.name/downloads/pubs/CNSM_10.pdf>>
>>Interestingly, in that paper (and you will recognize the author), there
>>is the notion of proxy with the REPORT-MIB Sorry proxy or "Do you
>>expect all MANET routers to always have connectivity to a static NMS?"
>>
>>
>>
>>
>>               * etc...
>>
>>
>>       Can't address that one :-)
>>
>>
>>               Obviously, monitoring, for example, is important in ad-hoc
>networks, but
>>               please let us know how you envision doing this. For
>>example, right now, I
>>               see the term "appropriate SNMP management stations", and I
>have no clue
>>               what's "appropriate" in the management of an ad-hoc
>>network.
>>
>>
>>       Frankly, I don't think we have a good answer to what
>>"appropriate" means in any network. Again, I am not sure why a MANET is
>>any different.
>>
>>       But I agree that "appropriate" is a bad word and I should have
>>let it through my review. Perhaps this is a Comment?
>>
>>Whether this is Comment or a Discuss is not relevant.
>>Let's not try to see every single line in this DISCUSS as a small thing
>>to fix... it seems to me that there is an elephant in the room.
>>
>>
>>At this point in time, I believe that a conf. with the authors would be
>>more beneficial
>>
>>Regards, Benoit.
>>
>>
>>
>>
>>
>>
>>               I see some other MANET MIB modules...
>>               * draft-ietf-manet-olsrv2-mib-04        Definition of
>Managed Objects for the
>>               Optimized Link State Routing Protocol
>>               * draft-ietf-manet-report-mib-02        Definition of
>Managed Objects for
>>               Performance Reporting
>>               * draft-ietf-manet-smf-mib-04   Definition of Managed
>Objects for the
>>               Manet Simplified Multicast Framework Relay Set
>>               However, this document is the first MANET MIB module to
>reach the IESG,
>>               so those operational questions are important.
>>
>>
>>       Agreed. The authors of those other documents are waiting on the
>>review of this document to help them with their work. The MIB Doctor
>>review was much anticipated. I agree that the answers to the questions
>>you have raised are equally applicable to the other documents. I think
>>the lessons learned about write access will be quickly applied to the
>>other document. But I have some trouble understanding the value of the
>>other questions - I just can't understand why a MANET is so
>>dramatically different in your eyes.
>>
>>
>>               If this is expressed in a different document, let me know,
>and I can
>>               review it.
>>
>>
>>       There is no other document on the applicability of managing
>>MANET devices.
>>
>>
>>               Along the same lines,
>>               1. see Al Morton's review, part of the OPS-DIR
>>
>>                       General question: Is a lossy, mobile ad-hoc
>>network
>compatible with
>>                       SNMPv3? In other words, will the link performance
>information needed
>>                       for troubleshooting really be available when it is
>needed most, and
>>                       critical nodes may be unreachable?
>>
>>
>>       Sorry, I have not seen Al's review.
>>       It looks like his question is "is it possible to run an IP-based
>>application over a MANET?"
>>       Answer: yes.
>>
>>
>>               2. Read Ron's Bonica's Abstain
>>
>>
>>       Read and discussed with Ron in person. Presuming you agree this
>>part of your Discuss is not actionable (or maybe the action is to read
>>Ron's comment
>>:o)
>>
>>
>>               COMMENT:
>>
>> ----------------------------------------------------------------------
>>
>>               - Abstract
>>
>>                  This document defines a portion of the Management
>Information Base
>>                  (MIB) for use with network management protocols in the
>Internet
>>                  community.  In particular, it describes objects for
>configuring
>>                  parameters of the Neighborhood Discovery Protocol
>>(NHDP)
>process on a
>>                  router.
>>
>>               Should this be "MANET router"?
>>               "MANET router" is used in RFC6130
>>               Alternatively, I see in this document:
>>                       "NHDP router"
>>                       "router in a Mobile Ad Hoc Network (MANET)"
>>               Same remark for the introduction, which uses the same
>>text.
>>
>>
>>       This can be cleaned up.
>>
>>
>>               - First occurence of NHDP must be expanded.
>>
>>
>>       It already is.
>>
>>
>>
>>
>>
>>
>>Classification: UNCLASSIFIED
>>Caveats: NONE
>>
>>
>>
>>Classification: UNCLASSIFIED
>>Caveats: NONE
>>
>>
>
>
>Classification: UNCLASSIFIED
>Caveats: NONE
>
>