[AGENT++] Creating Rows in Shared MIB Tables

[Frank Fock]

Jens,

A very good question! AgentX does not provide any mechanism
for sharing tables with a RowStatus column (thus tables where
rows can be created dynamically via SNMP requests).
There are three possible solutions:

1. The subagents are using preallocated index ranges, but this
requires that the managers know these ranges and the implicit mapping
to subagents (although this could probably extracted from the
AGENTX-MIB).

2. Use contexts as you suggested in your posting. Each subagent uses
its own context. But then you have no longer a shared table. Nevertheless,
there could be built a read-only shared table in the default context.

3. Use an object outside the table to create rows in the table.

I would strongly recommend approach (2). (1) might be useful depending
on the index of the sahred table. (3) is a hack.

May be you can forward your question to the AgentX mailing list.
Dynamic shared tables is probably worth a discussing for the next
AgentX version, isn't it Bob?

Best regards,
Frank

Jens Engel wrote:

>Hello,
>
>I just came across a conceptual problem when MIB tables are shared via 2
>subagents.
>NOTE: Currently, it is just a mind game.
>
>ENVIRONMENT:
>- 1 SNMP master agent with 2 subagents (via AgentX)
>- Each subagent provides a set of rows in a shared MIB table that it
>registers w/ master agent on startup
>- MIB table allows to create new rows
>
>QUESTIONs:
>- Can each subagent declare itself responsible in the AgentX master when
>table rows should be created?
>  NOTE: When certain values for the row index are used, creation occurs in
>subagent 1, otherwise in subagent 2.
>- How does a subagent describe this responsibility w/ AgentX++ ???
>
>
>POTENTIAL PROBLEM AVOIDANCE STRATEGY:
>The normal work-around this problem that came to my mind was the usage of
>CONTEXTs.
>Each subagent registers its portion of a MIB table (or MIB module) in the
>default context
>and a subagent specific context.
>This should allow to create rows in any subagent by making this decision in
>the SNMP client.
>For example, a subagent 1 registers its MIB modules in context "Subagent1".
>The subagent 2 registers its MIB modules in context "Subagent2".
>
>Ciao,
>Jens Engel
>
>
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