[SNMP4J] V2 Trap Packet Fragmentation

[Amol Rao]

...any thoughts? anyone?

On Mon, Apr 16, 2012 at 4:09 PM, Amol Rao <xamolrao at 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 <xamolrao at 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