Mib questions

[[e-mail] (Dan Romascanu)]

Hi David,

I think that you have asked a bunch of interesting questions,
and discussing all this could help those who are implied in writing
this MIB and intent to implement it realise whether we have a common
understanding what we are talking about. I would like to answer these
questions, not in order to give an authoritive answer but rather to
present how we understand what has been proposed untill now and how we 
try to implement it. I would be happy if others would do the same, it
could help us all.

> I've been trying to keep up with all the suggestions
> that have been going back and forth. Maybe these were
> covered, it so, sorry for the repeat. 
> 
> Questions:
> 1) What is the scope of the chassis MIB?  Is it limited
>    the the devices covered in the Overview (section 5)?
Yes, I think we should limit the scope to 'networking devices'
as defined in the Overview. It is very tempting to extend the
scope ('The sky is the limit') but in order to be effective we
should limit now the scope and maybe later, when we will have
some implementation experience try to solve other problems of
mankind.

> 2) Do the terms "functional module" and "logical device"
>    mean the same and are they things like routers, bridges,
>    terminal servers, etc?
Yes, I think so.

> 3) Is there a requirement that the "logical devices" have
>    network connectivity to each other (ie be able to pass
>    traffic to each other)?
If by 'to each other' you mean any logical device should be 
connected to any other logical device, no. But connectivity
exists between subsets of logical devices and it should be
known and understood from the information supplied by this MIB.
  
> 4) Can any "logical device" implement the chassis MIB?
No.

> 5) Must all the "logical devices" implement the chassis MIB?
No.

> 6) If more than one implements the chassis MIB, must all the
>    values be "consistent"?
If they refer to the same chassis instance, yes.
Otherwise. I can imagine configurations where different logical 
devices, implement different 'Chassis MIBs' in the same enclosure,
maybe with part of the information interleaved.

> 7) What is the minimal requirements for gathering information
>    that a "logical device" must have when implementing the MIB?
I think it should base the information upon gathering information
from the entities in the Chassis. Such a capability must be provided.

> 8) Is it valid that all the information in the slot table (and
>    most other MIB objects) be entered by a "configuration file"
>    that an agent loads at its boot time?
It can be, but how did this information get to the "configuration
file"? The right way on my opinion would be to gather the information
from the other entities in the chassis and to keep it permanently
updated.

> 9) What are some situations the it would be appropriate to use
>    a "sparse" slot table?

> 10) Is a "logical device" a realised hardward component which has
>     an unchanging identity, or does it also include "personalities"
>     that are identified by the software that is running on the
>     "logical device". An example would be a File server, loadable
>     RMON software, Mail server, or any other "application server".
This basically means that chasEntityFunction could change during
the chassis operation. Why not?
 
> A fundamentation question is just how is an agent that implements
> the chassis MIB suppose to get all the information about the other
> "logical devices" - 1) through SNMP requests to the other "logical
> devices", 2) through a private network protocol, 3) through a backplane
> bus using shared memory or messages between CPUs,  or 4) through some
> "static" configuration file that is loaded at agent boot time (and
> maybe refreshed during running)?
I really do not think that the Chassis MIB standard must address this 
question which is a matter of implementation. Anyway, in my opinion:
1) does not work in the SNMP framework, as all "logical devices" are
agents.
2) could work
3) the best
4) could work, but it is the least efficient.
 

> Thanks,
> /dave perkins, synoptics, 408-764-1516
> 
> 

[e-mail]

Dan Romascanu
Systems Group Manager

LANNET Data Communications Ltd.
Tel Aviv, Israel

Voice: 972-3-6458414
Fax:   [phone]