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Conference pamsrc::decmessageq

Title:NAS Message Queuing Bus
Notice:KITS/DOC, see 4.*; Entering QARs, see 9.1; Register in 10
Moderator:PAMSRC::MARCUSEN
Created:Wed Feb 27 1991
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2898
Total number of notes:12363

2781.0. "Timeout detection strategy" by GVA05::GUY () Thu Feb 20 1997 13:00

A customer is complaining about the long time that DECmessageQ uses
to  detect a node not reachable and therefore sends back the timeout
status. About 50 seconds.

He wonders if there is a way to decrease this timeout parameter in DECmessageQ.

Any information regarding this timeout process will be valuable.

Thanks

Jean-Paul.
T.RTitleUserPersonal
Name
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2781.1More background, pleaseXHOST::STUTZMANThu Feb 20 1997 13:208
    Please specify DmQ version, OS and network transports for:
    	non-reachable node
    	node on which non-reachable node is being monitored
    
    Additionally, is the node loss being tracked by AVAIL/UNAVAIL,
    the DmQ monitor and/or the link tracking provided by the
    link connected/lost msg-based API?
    
2781.2Speed up timeout detect when attachingGVA05::GUYFri Feb 21 1997 08:1118
>    Please specify DmQ version, OS and network transports for:
>    	non-reachable node
>    	node on which non-reachable node is being monitored

	DMQ3.2
        WNT 3.51
         dec chip 2.1040
    
>    Additionally, is the node loss being tracked by AVAIL/UNAVAIL,
>    the DmQ monitor and/or the link tracking provided by the
>    link connected/lost msg-based API?
    
They claim they can use AVAIL/UNAVAIL, but they would like if there is a way
to speed up the process of node unavailable during the first DMQ attachment.

Jean-Paul.

2781.3XHOST::SJZRocking the Messaging Desktop !Fri Feb 21 1997 12:2610
    
    you say you get a timeout status back in 50 seconds ?  where
    are you getting that ? Is this the result of a put operation ?
    have they registered for LINK_NOTIFY ?  what is it that they
    are currently using ?  How is the connection being broken (I
    assume that they are forcing the  link  down  condition,  by 
    shutting down the remote group ?  or  disconnecting  the  ma-
    chine from the network ?)
    
    _sjz.
2781.4Timeout on PAMS attachGVA05::GUYFri Feb 21 1997 14:183
They get this after the PAMS attach.

Jean-Paul.
2781.5XHOST::SJZRocking the Messaging Desktop !Fri Feb 21 1997 15:119
    
    what does that mean "after the PAMS attach." ?  they make what
    call and it returns what status ?  they send what message  and
    receive what message in return ?
    
    prior to V4.0, pams_attach_q does not return PAMS__TIMEOUT  on
    any of the non-VMS platforms.
    
    _sjz.
2781.6NO network detection ?GVA05::GUYFri Feb 28 1997 08:3512
Actually the customer doesn't experience PAMS_TIMEOUT, he is not able to give 
me the exact status he is getting, he thought maybe - 246 but is not sure.

He would like to know why DECmessageQ "takes so long time to see  that the 
network is down".

Is it possible to tell him a little more about the strategy DMQ uses to 
detect network presence.

Thanks

Jean-Paul
2781.7DmQ detects network link loss...KLOVIA::MICHELSENDECmessageQ EngineeringFri Feb 28 1997 10:3611
re: .6

...using two mechanisms: 1) transport layer errors that are returned to the Link
Drivers and a periodic ping of the link.  Therefore, if the underlying network
fails to deliver a timely notification of link loss the fall back is a ping
timeout.  Please note that the ping timeout can't be too short or the Link
Drivers will get false readings of link loss when the network is temporarily
congested.  To me 50 seconds is reasonable for a ping timeout to occur.


Marty
2781.8Timeout algorithm ?GVA05::GUYTue Mar 04 1997 15:363
Thanks a lot for this info, I pass it to the customer.

Jean-Paul.