[SNMP4J] problem receiving v3Traps over TCP using DefaultTcpTransportMapping

[Frank Fock]

Hi,

 From your description I conclude that the
trap senders open a new TCP connection for
each trap within 10 milliseconds, is that
right?

That's a bad design (even for testing), because
establishing a TCP connection is very expensive
and when closing it, resources may not be release
immediately.

500KByte Traps are questionable too. If there are
thousands of trap senders, you will need a 10Gbps
LAN instead 100Mbps and a really fast machine to
process the data.

Best regards,
Frank

shanmugam vairavan wrote:
> Hi,
> 
> 
> 
> I am using snmp4j (v1.9.2) for writing a V3Trap listener. The listener
> should be able to receive 'hundreds of thousands' of V3Traps per day, over
> TCP from multiple senders. When testing my listener implementation I found
> that my listener goes into a deadlock, and stops listening when the load
> increases (say 2 senders, sending Traps of size 500kilobytes per
> 10milliseconds). The listener is running on a machine with the following
> configuration: Intel Pentium (D) CPU 3.40GHz, Windows XP Professional SP3,
> 2GB RAM, 100Mbps LAN.
> 
> 
> 
> When the problem occurred, TCPView shows around 40 TCP connections (for my
> listener port) with almost all in ESTABLISHED state, barring a few in
> CLOSE_WAIT state. I have attached the same.
> 
> 
> 
> Debug reveled the reason for this problem being the
> java.nio.channels.Selector.select() call in
> DefaultTcpTransportMapping$ServerThread.run() method blocks forever. I even
> tried modifying the call with a timeout,
> java.nio.channels.Selector.select(10000). Now there is no deadlock but when
> the load increases the call always returns 0.
> 
> 
> 
> Has anyone faced a similar situation before? Is this problem inherent to TCP
> or the Sun's NIO implementation? Please provide me some pointers to solve
> the same.
> 
> 
> 
> PS: Please let me know if you need any further information regarding my
> setup and code.
> 
> 
> 
> Thanks & Regards
> 
> Shanmugam.VE
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