[SNMP4J] V2 Trap Packet Fragmentation

2012-04-16 Thread Amol Rao
Hi All:
  Just wanted to reach out and see if anyone encountered this situation.

I am sending out an SNMP trap (~1K size) from an agent system. When
manager receives the trap, its observe that its divided into multiple
traps and each trap carries one variable binding - which leads to
conclusion that the packets are getting fragmented at the SNMP level,
I wonder why this happens.

I did wireshark and realized that there is no UDP level fragmentation.

Both source (trap generation) and Destination (trap receiver) uses
snmp4j-1.11.jar but since on the receiving side, I have logic that
expects the trap to come in as one UDP packets, the whole thing breaks
apart. Moreover, I observed that its happening on only one system, the
same code works on another identical system.

Any pointers as to why this could be happening and what is the way around?

I am pretty sure that we are not crossing UDP packet limit, not that
it would matter at SNMP layer.

Thanks.

Cheers,
Amol
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Re: [SNMP4J] V2 Trap Packet Fragmentation

2012-04-16 Thread Amol Rao
...any thoughts? anyone?

On Mon, Apr 16, 2012 at 4:09 PM, Amol Rao xamol...@gmail.com wrote:
 I see the following exception when trap is being sent out. Any pointers?


 java.lang.NullPointerException
        at org.snmp4j.PDU.getBERPayloadLengthPDU(PDU.java:499)
        at org.snmp4j.PDU.getBERLength(PDU.java:436)
        at org.snmp4j.mp.MPv2c.prepareOutgoingMessage(MPv2c.java:118)
        at 
 org.snmp4j.MessageDispatcherImpl.sendPdu(MessageDispatcherImpl.java:444)
        at org.snmp4j.Snmp.sendMessage(Snmp.java:1078)
        at org.snmp4j.Snmp.send(Snmp.java:878)
        at org.snmp4j.Snmp.send(Snmp.java:871)
        at org.snmp4j.Snmp.send(Snmp.java:836)
        at org.snmp4j.Snmp.notify(Snmp.java:780)


 Cheers,
 Amol

 On Mon, Apr 16, 2012 at 1:05 PM, Amol Rao xamol...@gmail.com wrote:
 Hi All:
  Just wanted to reach out and see if anyone encountered this situation.

 I am sending out an SNMP trap (~1K size) from an agent system. When
 manager receives the trap, its observe that its divided into multiple
 traps and each trap carries one variable binding - which leads to
 conclusion that the packets are getting fragmented at the SNMP level,
 I wonder why this happens.

 I did wireshark and realized that there is no UDP level fragmentation.

 Both source (trap generation) and Destination (trap receiver) uses
 snmp4j-1.11.jar but since on the receiving side, I have logic that
 expects the trap to come in as one UDP packets, the whole thing breaks
 apart. Moreover, I observed that its happening on only one system, the
 same code works on another identical system.

 Any pointers as to why this could be happening and what is the way around?

 I am pretty sure that we are not crossing UDP packet limit, not that
 it would matter at SNMP layer.

 Thanks.

 Cheers,
 Amol
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