[Nsi-wg] time issue

[Radek Krzywania]

Hi,
Just a short comment on time definitions there - I kind of like them :) The case is that we should be able to estimate the difference between available and resource time - so in other words, to be able to estimate setup and tear down time. That is mostly for purposes of SLA, but not only. Also, since user is requesting only to give an available time, we need to map those times somehow, and keep them synchronised. This is implementation work here, but doable (if we are able to estimate setup/tear down times).

Best regards
Radek

________________________________________________________________________
Radoslaw Krzywania                      Network Research and Development
                                           Poznan Supercomputing and  
radek.krzywania at man.poznan.pl                   Networking Center
+48 61 850 25 26                             http://www.man.poznan.pl
________________________________________________________________________


> -----Original Message-----
> From: nsi-wg-bounces at ogf.org [mailto:nsi-wg-bounces at ogf.org] On Behalf
> Of John Vollbrecht
> Sent: Monday, September 27, 2010 11:51 PM
> To: NSI WG
> Subject: [Nsi-wg] time issue
> 
> Hello all -
> 
> Jerry and I had a discussion last week about the time issue.  I think we
> developed a useful approach.
> 
> The idea is to define two times, which I think we all agree exist.
> 
> 1) available time - time a connection is available to the application to
> communicate between devices
> 2) resource time - time a resource is reserved to support available time
> 
> To further define these -
> 
> Available time
> - requested by the user for its application
> - provided by the network.
> 
> resource time
> - time a resource is allocated to a connection
> - includes setup and teardown time, if any
> - is time in reservation calendar for resource
> 
> Available time requested cannot be provided exactly by network because it
> cannot predict exactly length of setup and take down.  I believe we all agree
> with this.
> Therefore provided available time can at best approximate requested
> available time.
> 
> We agreed that when a user requests automatic start connection it would
> request available time and the provider would schedule resource time to get
> as close as possible.
> When a request is for user initiated connection the time would be for
> reserved time, and the user initiation can start anytime after the reserved
> time.  Available time depends on setup and take down times of equipment.
> 
> -----------------
> I think we agreed on the above definitions.  The definition of time seem
> useful in discussing what goes in connection service messages.  We also
> talked about some possible implications of this.
> 
> The difference between available and resource time is setup and takedown
> time.  While it is impossible to be sure exactly how long they will be, it may be
> possible to define something statistical.  For example setup takes an average
> of 17 sec with std deviation of N.  If this is can be defined for the resource,
> then one can make a prediction about when a connection will be available
> with a degree of confidence.
> 
> For example this would allow one to request an automatic connection, for
> example, at 5pm and have it available 99% of the time.  If the average setup
> time is 17 seconds and I add 10 seconds to be 99% sure, then the service
> would initiate the connection at 5:00:00 - 0:00:25, or 4:59:35.
> 
> We talked about including this "setup requirement" in the connection service
> definition of and NSA, and by implication including this in requests and
> replies.  I think this is worth talking about in the group.
> 
> John
> 
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