Subject: Question on IndexNext objects.

From: [email-masked]
Date: Mon, 13 Apr 1998 08:17:21 -0400

Since I'm new to this list, I don't know if my question is something that
has already been discussed in the past.  If so, could someone please point
me to the discussion.

After implementing the atmVpCrossConnectIndexNext and
atmVcCrossConnectIndexNext objects, I've noticed that they are constantly
being incremented.  I'm using a standard management application (SNMPc from
Castle Rock) and it periodically walks the MIB issuing GetNext requests.
This has the undesirable effect of reading the IndexNext objects which
reserve an index value even though the operator has no intention of using
this value.  How do MIB implementors handle this situation?

The description of these objects states "the manager issues a management
protocol retrieval operation to obtain the current value of this object."
Does a "retrieval operation" include a GetNext or is it only on a Get that
the next value is obtained?  If a retrieval operation includes both Get and
GetNext, then all of the index values will get used up over time as
standard management applications periodically walk the MIB.  If a retrieval
operation is only a Get, then I don't think the MIB walking will be a
problem, but what value should be returned on a GetNext, a 0?

Don Cantwell
508-871-0555

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From: Gary Hanson <[email-masked]>
Date: Thu, 16 Apr 1998 20:50:14 -0700 (PDT)

Don,

> this value.  How do MIB implementors handle this situation?

The ATM-MIB does not impose any requirement that the entries are
in fact "reserved" by the act of reading the *IndexNext objects.
The values returned are simply suggested values that represent
currently unused index values, so resources should not actually
be "consumed" by this process.  It would suffice that the agent
simply cycles round-robin through the range of index values,
wrapping from 2147483647 back to 1 and skipping over values that
represent entries that have actually been created by management
action or by signalling protocols.

> the next value is obtained?  If a retrieval operation includes both Get and

Both Get and GetNext can be considered "retrieval operations".

> standard management applications periodically walk the MIB.  If a retrieval

As mentioned above, the index values should not be viewed as
being "used up", but are only being suggested to the management
application that wanted a hint about a currently unused index
value.  The values remain unused until an entry is created.

> problem, but what value should be returned on a GetNext, a 0?

The same value should be returned by a Get of the object as for
a GetNext of the lexicographically-previous object.

> Don Cantwell

I hope this helps.

Regards,
Gary