Re: scalars like ifNumber and ifTableLastChange

[Robert Snyder <[e-mail]>]

Bert,  Mayber I can help.

ifNumber
ifNumber is a poorly thought out object, it should have never been.
That said, I have run into more that one management station that can
not deal without its presence or misimplementation.  This is would
break a lot of fielded implementations, it remains

ifTableLastChange
As I recall the discussions around this certered around a need for a
hint as to whether the ifTable changed, since downloading the entire
table frequently is impractical for devices with say a 1000 interfaces

That said, if you object to these specific objects and get them nuked
that does not mean that a new wiz bang object that does have a
legitimate value wont come along and present the same issues for
agentX.

Does that help?

Robert

> Date:    Thu, 30 Jan 97 19:37:27 +0700
> To:      [e-mail]
> cc:      [e-mail], [e-mail], [e-mail]
> 
> From:    "Bert Wijnen" <[e-mail]>
> Subject: scalars like ifNumber and ifTableLastChange
> 
> Ref:  Your note of Thu, 30 Jan 1997 12:35:49 -0500
> 
> Subject: scalars like ifNumber and ifTableLastChange
> 
> I am crossposting again because Bob answer with copy to 3 mailing lists
> I prefer to move this to one mailing list.
> So let us decide this:
>   - if it is about agentX, then lets use agentX list
>   - if it is general SNMP then use snmpv2 mailing list.
> 
> I find Bob's "attack" on agentX a litle bit harsh... I know he means
> well though. I was not trying to justify agentX topics so much as
> I was trying to raise the issue w.r.t. to SNMP MIB-Views.
> 
> So let me answer that piece here.
> 
> Bert writes:
> >  - one can specify a MIB-view in which ifNumber and ifTableLastChange
> >    are included, some rows in the ifTable are included and other rows
> >    in the ifTable are excluded.
> >  - If a manager now gets ifNumber and then walks the table, then
> >    it turns out that the ifNumber is in many cases not equal
> >    to the number of rows that thus manager can get.
> >  - If a manager now gets ifTableLastChange, then he may see that
> >    this object tells him that a change took place, but in the
> >    table that he retrieves he sees no changes at all.
> >I understand that this is not a real serious problem.... but as I
> >have stated before, it makes one wonder what the heck these 2
> >objects contribute in terms of usefull information.
> >
> 
> To which Bob answers:
> >People who limit their SNMP views in silly ways get silly results.
> >
> 
> So... you think that that is silly.
> Mmmm... I see that specifically the ifTable is used as an example.
>         So that then is a bad example I guess.
> Mmmm... If such a definition is silly... then certainly we should
>         not use the ifTable as an example. And... if we cannot
>         find any better (real and smart samples), then maybe
>         we should do away with some of that complex MASKing stuff
>         for MIBviews.
> Mmmm... I have also heard so often the ISPs and Telcoes need such
>         fine granularity for MIBviews because they want each of
>         their customers to see only their own stuff and not that
>         of other customer.s
> Mmmm... So if they do that silly thing, then at least I can see
>         that this ISP or Telco has at least ifNumber of customers.
> 
> Oh... well, mybe Bob can explain his statement a bit better
> I seemed unable to understand it as it was written.
> 
> Bert