Re: [ws-rx] i130 - what does ack interval refer to

[Doug Bunting <Doug.Bunting@Sun.COM>]

I also prefer removal but would put option 2 above option 1 even for 
your use case because it better handles lost messages from the RMS to 
the RMD.  Again, I dislike making decisions based on missing information 
(the absence of an acknowledgement at the expected time).

The added message or two when the RMS is indeed not sending doesn't seem 
like spam.

Anyone planning on including the interval in the CSR?  Anyone planning 
to use the value provided should their RMS receive it?  If so, for what 
purpose?

thanx,
    doug

On 22/06/06 10:18, Doug Davis wrote:
>
> +1  I always thought of AI in terms of option 1 but could also live 
> with its removal.
> Using it as a heartbeat is not something I'm very excited about since 
> in long-lived
> Sequences it will generated quite a lot of spam.  And, if in those 
> situations, you make the
> AI large enough to not turn Acks into spam then the RMS would be 
> forced to send
> AckReqs anyway to get timely Acks - relegating the AI to a meaningless 
> value.
> -Doug
>
>
>
> *Christopher B Ferris/Waltham/IBM@IBMUS*
>
> 06/22/2006 06:54 AM
>
> 	
> To
> 	Doug Bunting <Doug.Bunting@Sun.COM>
> cc
> 	Bob Freund-Hitachi <bob.freund@hitachisoftware.com>, Doug 
> Davis/Raleigh/IBM@IBMUS, Doug.Bunting@Sun.COM, ws-rx@lists.oasis-open.org
> Subject
> 	Re: [ws-rx] i130 - what does ack interval refer to
>
>
>
> 	
>
>
>
>
>
>
> IMO, Option 1 was the intended meaning... the interval following 
> receipt of a message
> before an Ack is sent.
>
> Thus, an RMS could guage whether it might want to retransmit a message 
> if, after the ackInterval
> had elapsed, it had not seen an ack for a message that it had just 
> sent. Its purpose was also to allow
> for optimization of acks, such that in the case where there are 
> multiple messages received within
> the interval, the RMD could bundle up a "number of acks" into a single 
> SeqAck, conserving
> bandwidth.
>
> That said, I think Bob's characterization below is about right 
> regarding the fact that we really don't
> need it at all, and I would certainly support option 3.
>
> One last clarification, just in case some of what was stated makes it 
> into clarified text
> (should we choose to keep it), the original note in this thread had 
> the following:
>
> > > Option 1 means that the RMD will wait no longer than the AI value
> > > before it sends an Ack. The
> > > RMS can be assured that if it doesn't get an Ack from the RMD after
> > > that time then the Ack
> > > was lost.  Note: a new msg into the RMD initiates the timer and the
> > > sending of an Ack stops it.
>
> Actually, it would be more like:
>
> Option 1 means that the RMD SHOULD wait no longer than the AI value
> before it sends an Ack after receiving a message. The RMS can assume
> that if it doesn't get an Ack from the RMD after
> the AI has elapsed following the transmission of a message from RMS to
> RMD, then there is a probability that the message was
> unsuccessfully transmitted and hence, the message SHOULD be 
> retransmitted.
> The RMD is always free to send an Ack anytime before the AI has elapsed.
>
> Cheers,
>
> Christopher Ferris
> STSM, Software Group Standards Strategy
> email: chrisfer@us.ibm.com
> blog: http://www.ibm.com/developerworks/blogs/dw_blog.jspa?blog=440
> phone: +1 508 377 9295
>
> Doug.Bunting@Sun.COM wrote on 06/21/2006 11:12:16 PM:
>
> > Sorry, I missed this email before sending my last message.
> >
> > OK, we have option 3: Eliminate the acknowledgement interval from the
> > specification.
> >
> > As Doug knows, I was having trouble finding a compelling purpose for
> > this value from an RMS perspective.  Perhaps, a hint for the RMS Make
> > Connection interval?
> >
> > I was also thinking option 3 effectively re-opens an old issue but
> > didn't go looking...
> >
> > thanx,
> >     doug
> >
> > On 21/06/06 18:46, Bob Freund-Hitachi wrote:
> > >
> > > There were previous arguments concerning ack interval.  At that 
> time I
> > > was one that argues that it was unnecessary since efficient
> > > implementations, from a latency point of view, would immediately ack
> > > and that ack range could be used as an optimization based on system
> > > load if there were more than one message to ack at the point when the
> > > ack was to be sent.  Others argued that the ack interval could be 
> used
> > > as a “hint” to either create more opportunities for this optimization
> > > or to allow perhaps ack piggybacking on response.  In both of these
> > > arguments it would need to be the time that the acknowledger would
> > > hold-off from sending the acknowledgement simply to permit such an
> > > optimization to occur.  I still maintain that this is ill advised and
> > > an unhelpful feature. But it is consistent with your case 1.
> > >
> > > The second alternative that you discuss is not discussed as far as I
> > > remember.
> > >
> > > I suggest that clarification is best performed by eliminating the 
> feature.
> > >
> > > Thanks
> > >
> > > -bob
> > >
> > >  
> > >
> > > 
> ------------------------------------------------------------------------
> > >
> > > *From:* Doug Davis [mailto:dug@us.ibm.com]
> > > *Sent:* Wednesday, June 21, 2006 9:32 PM
> > > *To:* ws-rx@lists.oasis-open.org
> > > *Subject:* [ws-rx] i130 - what does ack interval refer to
> > >
> > >  
> > >
> > >
> > > All,
> > >   Doug Bunting and I have been discussing issue 130 ("what does ack
> > > interval refer to")
> > > and we've hit a bit of a roadblock.  There are two (perhaps more) 
> ways
> > > of interpretting
> > > what the AckInterval (AI) value is meant to be used for, or what its
> > > intended meaning is supposed
> > > to be.  The two, most likely, options are:
> > > 1 - the maximum time the RMD will wait, after receipt of a message,
> > > before an Ack will be sent
> > > 2 - the maximum time the RMD will wait before between sending Acks
> > >
> > > Option 1 means that the RMD will wait no longer than the AI value
> > > before it sends an Ack. The
> > > RMS can be assured that if it doesn't get an Ack from the RMD after
> > > that time then the Ack
> > > was lost.  Note: a new msg into the RMD initiates the timer and the
> > > sending of an Ack stops it.
> > >
> > > Option 2 means that the RMD will send out an acknowledgement, at
> > > least, every AI milliseconds.
> > > Sort of like a heartbeat.  The RMS can be assured that it will not
> > > need to wait any longer than the
> > > AI before an Ack will be resent.  Note: the sending of an Ack will
> > > reset the timer and it will only stop
> > > upon termination of the sequence.
> > >
> > > Note: in both options the RMD is always free to send more acks and 
> the
> > > RMS is always free to
> > > send an AckReq - but we're not worried about those situations.
> > >
> > > The current wording is a bit ambiguous.So, the question for the TC
> > > is....which option do we
> > > want to present in the spec?  Thoughts?
> > >
> > > thanks,
> > > -DougD
> > >