[SNMP4J] Performance issue with single SNMP session

[bretonlais at gmail.com]

Hi,

I'm having an issue sending/receiving a large number (>50 at a time) get
PDU's to approximately 200 different SNMP agents using a single SNMP
instance. The problem I am having is two-fold:

One, since my requests are synchronous, I have to synchronize the send
method and wait for a response from the snmp session, which is a bottleneck
for my application.
Two, I've attempted to do away with the synchronization, but then most of my
responses return null when I parse the PDU response.

Is there a way to correct this performance problem? Or do I need to create
an snmp session each of my 200 different devices? Please advise. I've tried
asynchronous methods, but I seem to run into the same type of problem. I've
included a section of my SNMP implementation


    public PDU get(String oid, String community,
                            String targetIP) throws SnmpException {

        VariableBinding var = new VariableBinding();
        var.setOid(createOID(oid));

        PDU request = new PDU();

        request.add(var);
        request.setType(PDU.GET);

        Target target = createTarget(community, targetIP);

        PDU response = null;
        try {
            response = send(request, target);
        } catch (IOException ex) {
            logger.error("Error sending getPDU {} ", ex.getMessage());
        }

        return response;

    }

    private synchronized PDU send(PDU request, Target target) throws
IOException
    {
        PDU response = null;
        ResponseEvent responseEvent;
        //long startTime = System.currentTimeMillis();
        responseEvent = snmp.send(request, target);

        if (responseEvent != null) {
            response = responseEvent.getResponse();

            //logger.info("Received response for {} after {} millis. " ,
target.getAddress(),System.currentTimeMillis()-startTime);
        } else {
        }

        return response;
    }

    private Snmp createSnmpSession() {
        Snmp snmpSession = null;
        AbstractTransportMapping transport;

        threadPool = ThreadPool.create("DispatcherPool", 10);
        MessageDispatcher mtDispatcher =
                new MultiThreadedMessageDispatcher(threadPool, new
MessageDispatcherImpl());
        mtDispatcher.addMessageProcessingModel(new MPv1());
        mtDispatcher.addMessageProcessingModel(new MPv2c());

        try {
            transport = new DefaultUdpTransportMapping(new UdpAddress("
0.0.0.0/161"));
            snmpSession = new Snmp(mtDispatcher, transport);
        } catch (IOException ex) {
            logger.error("Unable to create SNMP session {} ",
ex.getMessage());
        }
        return snmpSession;

    }

Thanks,
Matt