[AGENT++] SharedTable Row Registration after Restart of Master-Agent

[Jens Engel]

I observed a problem related the registration of SharedMibTable rows after
the Master-Agent was restarted.

SCENARIO:
Master and Subagent both implement different rows in a shared MibTable, for
example IF-MIB::ifTable.
After the subagent connects itself to the master via AgentX, everything is
fine:
The subagent rows of the SharedMibTable can be retrieved by an SNMP client.
When I stop the master agent and restart it after a while, only the
subagent rows are no longer accessible
(even after it reconnects to the master agent).

PROBLEM DIAGNOSIS:
The problem seems to be that subagent rows are not re-registered via AgentX
when handleReconnect() occurs.

During the initial startup the subagent rows are discovered and are
registered via AgentX after the MibTable is registered.
After restart of the master agent, the subagent only registers its
SharedMibTable again via AgentX, but not the already existing rows.

When I re-register all existing SharedMibTable rows in my subagent's
reconnect handling, everything is fine again.

NICE TO HAVE:
Agentpp::SharedMibTable should have a (virtual) handleReconnect() (or
reregisterAllRows()) method that reregisters all existing rows.

Ciao,
Jens Engel.

mailto:Jens.Engel at marconi.com