Subject: Comments DISMAN Framework

From: Bert-Jan van Beijnum <[email-masked]>
Date: Thu, 19 Nov 1998 13:03:50 +0100

Dear Steve,

I'm one of the six guys who raised its finger for
providing you feedback on the DISMAN Framework.
I know, I'm far too late with my comments.
Nevertheless, I've seen no feedback on the framework
in the mailing list so far, and so it might be useful for
you to receive some comments anyway.

  Kind regardds,
  Bert-Jan van Beijnum

=========

Comments on Distributed Management Framework
<draft-ietf-disman-framework-02.txt>

The comment, remarks, questions etc. are all
related to Chapter 5 of the Framework document.
Here it is:

1. About Services - Applications - Functional Elements

Quote (page 6, 1st paragraph):
       "The distributed management framework consists of 
        applications and services."
Observation:
        The framework is not based, or does not specfify, 
        functional and/or physical elements from which a 
        distributed management system may be built.
        On the other hand, when looking at for instance the 
        Credential Delagation service (section 5.4, page 8..), 
        there seems to be a need for introducing functional 
        elements (namely: Manager, Distributed Manager and 
        Management Target).
        Also, in section 5.8 a need is suggested to delegate 
        functions to MLMs (note: MLM are not being described
        or introduced else where in the document).
Conclusion:
        There seems to be a need for basing the framework 
        not only on services and applications, but also on,
        say, functional elements. Therefore, I propose to include 
        this in the framework document. Here's my suggestion:

--- Add chapter 5 (and make it as last paragraphs just before 
    the start of section 5.1): ---

"A distributed management system may be constructed by using 
the following three different (functional) elements, each element 
supports or implements a distributed management service:

 o Manager (M) - a manager is capable of initiating/sending operations 
   and receiving notifications.

 o Distributed (or Mid-Level) Manager (MLM) - a mid-level manager is 
   capable of sending and receiving operations and it can send and 
   receive notifications.

 o Management Target (MT) - a management target is capable of receiving 
   operations and it can send notifications.

These components are shown in Figure 1 together with the
operations and notifications that each component is capable
of receiving and/or sending.

+---------+Opr     Opr+-----------+Opr     Opr+----------+
|         |-->     -->|Distributed|-->     -->|Management|
| Manager |           |(Mid-Level)|           |          |
|         |<--     <--|  Manager  |<--     <--|  Target  |
+---------+Ntf     Ntf+-----------+Ntf     Ntf+----------+

Opr = Operations
Ntf = Notifications

---End of Add

2. Mandatory and optional distributed services.

Quote (chapter 5, 3rd paragraph, page 6):
    "Some of these services are mandatory, while others are 
     optional."

Question:
    Which ones are mandatory and which ones are optional?
    May be I missed something, but I think it is not 
    specified/described in the framework document.

3. Management Domains

Questions:
   Is there a fundamental reason to define Management 
   Domains on basis of (human) organisational boundaries?
A thought:
   If not, may be one may look at Management Domains as 
   being of a (semi-) permanent character that may be based 
   on (human) organisational boundaries or some functional 
   criteria.
   Suggestion (replace 2nd paragraph of section 5.2 by):
     "These domains are multiple, potentially overlapping, sets 
      of devices based on criteria of a (semi-)permanent character 
      that define the extents over which management operations 
      should be performed. These criteria are based organisational 
      bounderies or function types."

Remark:
  In our group we have discussed the DISMAN draft, hence also the
  framework document. And we have tried to look at the relationship
  between Known Systems, Management Domains and Management Operations 
  Target. A picture reflecting our interpretation can be found on the
  following URL:
    http://wwwsnmp.cs.utwente.nl/nm/education/advanced-modules/disman-1/1-frame
work.pdf
    (the second slide).

4. Reliable Notification (Section 5.7)

Remark: The text suggests that notifications and events are 
        the same 'things' (for instance, when reading the
        second paragraph of this section).
Suggestion is to make the text consistent.

Observation: Only notifications can be logged.
Question   : Why not also log the events that caused the notifications?

5. Notification Destinations (Section 5.8)

Remark: the notion MLM has not been yet been introduced.
Solution: see also "1. Services ..." at the top of this email.

Quote (2nd paragraph of section 5.8):
   "Additionally, retry counts and numbers need to be configured."
Question:
   What are these "numbers", it is not totally clear to me, 
   are they the 'Notification ids'?

Quote (2nd paragraph of section 5.8):
   "Average and burst notification rates need to be defined"
Question 1:
   What is meant by 'defined'? 
Question 1:
   Is there a relationship with the second paragraph of Section 5.5?
   That is, are they (partially) the same?
Question 2:
   Do these rates have to be defined per destination, or for the
   sending entity as a whole, or is open?

==== That's it!

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

                   Bert-Jan van Beijnum

TTTTT  SSSS  SSSS  Telematics Systems and Services
  T   S     S      Department of Computer Science
  T    SSS   SSS   University of Twente
  T       S     S  P.O.Box 217
  T   SSSS  SSSS   7500 AE  Enschede, the Netherlands

                   phone: +31 53 489 2834
                   fax  : +31 53 489 3247
                   email: [email-masked]
                   www  : http://wwwhome.cs.utwente.nl/~beijnum
===============================================================

---

From: Randy Presuhn <[email-masked]>
Date: Thu, 19 Nov 1998 13:39:20 -0800 (PST)

Hi -

> Date: Thu, 19 Nov 1998 21:57:07 +0100
> From: Aiko Pras <[email-masked]>
> To: [email-masked], [email-masked], [email-masked]
> Subject: Re: Comments DISMAN Framework
> References: <[email-masked]> <[email-masked]>
...
> I'm affraid I agree with Juergen and Andrey. I've read the framework
> carefully and discussed it with several people. My observation is that
> it is a nice explanation of SOME concepts of DISMAN (although TMN and
> research papers present more info), but it is absolutely not necessary
> to read the framework if you want to understand the various MIBs (I've
> read
> all of them too).
>
> In fact I found that the framework can even be confusing. While
> discussing
> DISMAN with guys from a Dutch network provider, I found that they
> expected 
> that each MIB would define one of the services of the framework. That's
> clearly not the case, so they got confused.
...

I agree that a lot of the work in other organizations, including the
ODMA work, 10164-19, and even some of the earliest parts of 10164 go
beyond what the disman framework addresses in any depth.  This working
group's origins go back to the recognition within the IETF that there's
more to management than SNMP and MIBs.  Although a lot of hard work has
been put into this working group's projects, I feel we're still largely
in a "catch-up" mode with respect to these other organizations.

This SHOULD give us the advantage of being able to pick and choose
from among the successful ideas, and to avoid the tar pits.  What I've
seen, however, is that a small number of people (on the order of five
or so) has done virtually all the work.  In reponse to a recent call
for comments on one of our documents, I heard from exactly ONE person,
who has already given time to this effort far above the call of duty.
This does not exactly inspire confidence that we're on a path that enjoys
industry support.

Various drafts have been posted on topics that should be germane to this
group, including such interesting things as service level management
and dealing with retrieval of large chunks of management information.
But no one seems to have anything to say...

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---

From: Randy Presuhn <[email-masked]>
Date: Thu, 19 Nov 1998 14:21:48 -0800 (PST)

Hi - 

> Date: Thu, 19 Nov 1998 15:57:21 -0500
> To: "[email-masked]" <[email-masked]>
> From: Bob Stewart <[email-masked]>
> Subject: Re[2]: Comments DISMAN Framework
> 
> At 12:01 PM 11/19/98 -0800, Andrey Ter-Zakhariants wrote:
> >     It looks like this group is way behind CMIP, TMN etc. inventing the 
> >     wheel.
> 
> Actually the other attempts to define interoperable, widely deployed
> network management look more like flat tires.
> 
> 	Bob

Should I interpret this as yet another voice in favor of tossing the
framework?

If pursuing this work will plunge us into the sniping that has
historically plagued this field, then I suggest we stick to the various
more-or-less proprietary frameworks our respective companies already use
and drop any effort to standardize, since all previous efforts have so
obviously been such a complete waste of time.  I mean, no organization
of any real size would even contemplate using TMN, would they?

</scarcasm>

---

From: Randy Presuhn <[email-masked]>
Date: Thu, 19 Nov 1998 16:07:37 -0800 (PST)

Hi - 

Now, can we get back to the substance of Bert-Jan's comments
on the framework document?