[snmp] slow snmp v3 discovery timeout

[Birgit Arkesteijn]

On Tue, Jan 30, 2007 at 10:53:50AM +0530, Gejo.Thayil at aricent.com wrote:
> >In working with snmpv3 contexts, I've found that sending a Pdu
> >request to 
> >an
> >agent is not there takes a long time to return ~19 seconds. When I
> >looked
> >into the code, it looks as though the v3 context is using a 
> >UsmDiscoveryBean
> >to discover the v3 engineid and other parameters if that agent has
> >never been contacted.
> 
> 
> well in my case i was working with Westhawk Stack version 4_13, i have 
> switched off 
> the authentication and privacy flags in the context. also while 
> initialising the context 
> call TimeWindow.setSnmpEngineId(host, port, engineId), this will stop
> the discovery of engineId every time before sending a packet


That would certainly help if you know what the engineId is.
However, Gejo, I would like to point out that the stack doesn't do
recovery "every time before sending a packet".
It only does it if the engineId is unknown, i.e. the first time and when
discovery failed previously (Josh's problem).


> >The bean class uses the default timeout when sending the Pdu
> >request for discovery. However, I had set a different retry_array on
> >the
> >original Pdu that is causing the discovery to be sent in the first
> >place. 
> >It
> >would make sense for the stack to use this retry array when sending
> >the
> >discovery Pdu as well. Or at a minimum provide a way to change the 
> >default
> >retry array for v3 discovery. Perhaps there is another way to do this 
> >that
> >won't take so long that I am missing.. suggestions welcome.
>  
> >Josh
> 
> 
> why don't you add the same retry array before v3 Discovery, i.e in 
> UsmDiscoveryBean.java 
> when you are creating an instance of DiscoveryPdu, just call method 
> pdu.setRetryInterval(retry_array)
> and set the retries required there.


I'm not sure that is possible. 
pdu.setRetryInterval is not a static method:
( public void setRetryIntervals(int rinterval[]) )

and I don't see how you'd get your hands on the DiscoveryPdu object,
created in UsmDiscoveryBean (that is created in SnmpContextv3Basis).

I agree with Josh, parameters such as the retry_interval should be
copied from Pdu to DiscoveryPdu via UsmDiscoveryBean.
That probably means new methods
- Pdu.getRetryIntervals()
- UsmDiscoveryBean.setRetryIntervals()


> Regards
> Gejo Joseph


Cheers, Birgit

-- 
-- Birgit Arkesteijn, birgit at westhawk.co.uk,
-- Westhawk Ltd, Albion Wharf, 19 Albion Street, Manchester M1 5LN, UK
-- tel.: +44 (0)161 237 0660
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