[Nsi-wg] Immediate/Advance reservation (Re: NSI conf call minutes)
Joe Mambretti
j-mambretti at northwestern.edu
Tue Apr 13 15:51:26 CDT 2010
I agree with these comments.
At 08:42 AM 4/13/2010, Radek Krzywania wrote:
>Hi, Indeed, I forgot about NTP. But still my
>opinion is that we are unable to assure time
>precision at the level of seconds.
Yes, seconds in a metro area.
>Minutes are far more probable.
However, certainly in the near term (e.g., the
next two years). minutes are to be expected.
Furthermore, in part because of this timing
issue, as I have noted previously, the
distinction between "Immediate" and "Advanced" is
artificial. *All* requests are for future
resources. There is no reason to treat a request
for resources required "as soon as possible" from
other requests. The only difference is timing,
and all the timing is in the future. These issues
of timing belong to an external scheduler - not
to the protocol, except possibly in terms of a
time-to-live flag for the signal.
> Regarding race conditions, it's not the role of the protocol to prevent it.
I very much agree with this. There is a tendency
in these types of initiatives to expand the scope
of the standard. These tendencies should be resisted vigorously.
> Protocol operates in the area of single
> service definitions (how to request and process
> the request), while software will deal with
> simultaneous requests at different states and
> distributed in time (also overlapping). That's
> my opinion, unless someone will convince me
> otherwise :) Best regards Radek
> ________________________________________________________________________
> Radoslaw Krzywania Network
> Research and
> Development
> Poznan Supercomputing
> and radek.krzywania at man.poznan.pl
> Networking Center +48 61 858 20
> 28
> http://www.man.poznan.pl
> ________________________________________________________________________
> > -----Original Message----- > From: Artur
> Barczyk [mailto:Artur.Barczyk at cern.ch] > Sent:
> Tuesday, April 13, 2010 3:28 PM > To:
> radek.krzywania at man.poznan.pl > Cc: 'Inder
> Monga'; nsi-wg at ogf.org; 'Guy Roberts' >
> Subject: Re: [Nsi-wg] Immediate/Advance
> reservation (Re: NSI conf call >
> minutes) > > > > On 04/13/2010 03:14 PM, Radek
> Krzywania wrote: > > Hi, > > > > What is a hard
> deadline service? Any example? Is it
> synchronised with > > GPS? With what is it
> synchronised? What does it mean I want a > >
> reservation at 14:34 GMT? Is it 14:34 on
> requestor clock, atomic clock > > in e.g.
> Switzerland, synchronised GPS time (still ms of
> differences)? > > Different time zone,
> different clocks. If you not synchronise
> domain > > clocks you can�t talk about time
> in so exact manner as I feel you want > > to.
> Which clock are we referencing? > > I think
> it's not as bad as it sounds, NTP precision is
> enough at the time > scales we will ever be
> able to aim at reaching. :-) > > Being honest
> � I am not really > > against
> �thrashing�, and especially not against
> race conditions. It will > > be an issue when
> number of request will be quite high and
> competition > > for resources will be high. For
> now, facing the current demand for > > dynamic
> services, it�s not an issue at all. Not in
> version 1. Besides, > > how to solve race
> conditions is more an implementation issue (out
> of > > scope then), not a protocol. > > Radek,
> here I think you're wrong, sorry. In the
> context of multi-domain, the > protocol has to
> be defined in a way to avoid pitfalls such as
> race > conditions. > (among other things) > >
> Cheers, > Artur > > > > > > > > > Best
> regards > > > > Radek > > > > > > > >
> ________________________________________________________________________
> > > > > Radoslaw
> Krzywania Network Research
> and
> Development > > > >
> Poznan Supercomputing
> and > > > > radek.krzywania at man.poznan.pl > >
> <mailto:radek.krzywania at man.poznan.pl>
> Networking Center > > > > +48 61 858 20
> 28
> http://www.man.poznan.pl > > > >
> ________________________________________________________________________
> > > > > > > > > *From:* Inder Monga
> [mailto:imonga at es.net] > > *Sent:* Tuesday,
> April 13, 2010 2:49 PM > > *To:* Artur
> Barczyk > > *Cc:*
> radek.krzywania at man.poznan.pl; nsi-wg at ogf.org;
> 'Guy Roberts' > > *Subject:* Re: [Nsi-wg]
> Immediate/Advance reservation (Re: NSI conf
> call > > minutes) > > > > > > > >
> All, > > > > > > > > I agree about
> deterministic behavior. That is what we are all
> shooting > > for :) I am thinking in terms of
> state machines as well. > > > > > > > > What I
> am hearing both of you state that "Start Time"
> is not really a > > "Start time"...it is ASAP
> after "Start time" in case things are not > >
> complete? This is fine for a data movement
> service without hard > > deadlines, how will
> you ensure this for a Video conf system that
> needs > > to start at a particular time? We
> have to think of all possible > > application
> services that can use NSI. > > > > > > > >
> Radek, maybe Guard-time is being misunderstood
> - I am merely suggesting > > a gap before which
> Advanced Reservation Requests are not processed
> by > > the domain. There is nothing
> non-deterministic and immeasurable about > >
> that. It is a fixed value, albeit arbitrary
> value. This reduces the > > chances of the
> provisioning system across domains from
> "thrashing" - > > i.e. reserving resources and
> maybe releasing them because the connection > >
> did not happen in time. > > > > > > > >
> Regardless of the decision on guard-time, for
> deterministic behavior for > > many error
> conditions including start time arriving and
> reservation is > > incomplete and start time
> arriving and provisioning is
> incomplete. > > > > > > > > > > > > Enjoying
> the discussion, > > > >
> Inder > > > > > > > > > > > > > > > > On Apr
> 13, 2010, at 5:26 AM, Artur Barczyk
> wrote: > > > > > > > > Hi Radek, > > > > agree,
> but just to note, it's not about deterministic
> time, but > > deterministic > > behaviour I am
> worried about. > > I don't see a stable system
> where one part can be in provisioning > > while
> another in reservation. Guard time will not
> solve this by itself, > > even if you make it 2
> months :-) > > > > Cheers, > >
> Artur > > > > > > On 04/13/2010 02:15 PM, Radek
> Krzywania wrote: > > > > Hi, > > > > I
> tried to catch up the discussion, hope I did
> not missed anything. > > > > What is hard
> for me to understand is why are we trying to
> define > > measurable parameters
> (connection activation time) basing
> on > > non-deterministic, immeasurable
> parameters (guard time). Even if
> we > > measured how much time it takes to
> reserve and activate connection > > in a
> domain, we have only statistical view on how
> much time it MAY > > (SHOULD) take. Any
> change to the network, NSI architecture, HW,
> or > > even SF may extend this time
> unexpectedly, without
> prior > > notification. This is not
> something we can measure (or we need to
> do > > that constantly, changing guard time
> value every time, which in fact > > does
> not solve everything). IMHO we can't promise
> something we could > > not prove or be sure
> of. I am happy to measure guard time, add
> safe > > value (e.g. res + activation takes
> 4 minutes, + 2 minutes safe time > > = 6
> minutes) and say to we SHOULD deliver a
> connection in less than > > 6 minutes. If
> we say we MUST provide it in less than 6
> minutes, we > > have an
> issue. > > > > I am rather more familiar
> with the option where connection
> is > > delivered as soon as possible, which
> means each domain performs > > reservation,
> then signalling is initialized immediately
> after > > resources are booked. Does user
> care if he gets it now = current > > time,
> or = current time + "gurad time or whatever"? I
> suppose not. > > If I want a circuit now, I
> expect to get it ASAP, which does
> not > > means it's deterministic. I am fine
> with knowledge I will get it > > around 6
> minutes (statistically), but I must be
> immediately notified > > about activation.
> If we want to go into time details, we will
> get > > into very funny things like GPS
> synchronisation between users,
> NSA > > agents, networks, and domains. This
> is not a real-time system,
> not > > everything is deterministic, and
> not everything can be guaranteed. > > We
> can reconsider naming of the service, and
> change it from > > immediate to
> ASAP. > > > > I am not sure if we should
> focus on this small issue, while
> facing > > resources guarantee in advance
> reservation mode. Try to
> guarantee > > there anything for 100% in 2
> months time period:) Even if you
> assume > > no network/HW
> failures. > > > > > > > > Best
> regards > > > > Radek > > > > > > > >
> ________________________________________________________________________
> > > > > Radoslaw
> Krzywania Network Research
> and
> Development > > > >
> Poznan Supercomputing
> and > > > > radek.krzywania at man.poznan.pl
> <mailto:radek.krzywania at man.poznan.pl> > >
> Networking
> Center > > > > +48 61 858 20
> 28
> http://www.man.poznan.pl > > > >
> ________________________________________________________________________
> > > > > > > > > > > > > -----Original
> Message----- > > > > From:
> nsi-wg-bounces at ogf.org
> <mailto:nsi-wg-bounces at ogf.org> > >
> [mailto:nsi-wg-bounces at ogf.org] On Behalf
> Of > > > > Artur
> Barczyk > > > > Sent: Tuesday, April
> 13, 2010 10:11 AM > > > > To: Inder
> Monga > > > > Cc: nsi-wg at ogf.org
> <mailto:nsi-wg at ogf.org>; Guy
> Roberts > > > > Subject: Re: [Nsi-wg]
> Immediate/Advance reservation (Re:
> NSI > > conf
> call > > > > minutes) > > > > > > > >
> Hi Inder, > > > > > > > > I see,
> thanks for this
> clarification. > > > > > > > > I still
> think we are introducing an artificial decision
> step > > here,
> which > > > > will just be confusing to
> the end-user (and make the whole
> system > > > > more complex), and I
> still wonder about the necessity of
> it. > > > > Please see
> in-line: > > > > > > > > > > > > On
> 04/12/2010 11:15 PM, Inder Monga
> wrote: > > > > Hi
> All, > > > > > > > > I feel there
> is a lot of confusion, so let me try to explain
> my > > > >
> case/understanding. > > > > > > > >
> 1. Guard-time: > > > > This concept
> was proposed for Advanced Scheduling only.
> This > > can be
> a > > > > default value and it does
> not have to be an
> "exact" > > measurement
> of > > > > provisioning times. It
> only handles path computation
> and > > reservation > > > >
> times across
> domains. > > > > > > > > What does
> it mean to a user? > > > > A user
> CANNOT ask for a advanced reservation
> connection with > > Tstart
> < > > > > Tnow + Guard-time. If a
> user asks with a Tstart lower
> that > > Tnow
> + > > > > Guard-time, the scheduled
> request is rejected
> outright. > > > > > > > > Imagine I try
> to make a connection "NOW", and it gets refused
> after > > > > N minutes due to lack of
> resources. Then I try "2 minutes
> from > > now", and > > > > it
> gets rejected straight off. > > > > We
> shouldn't aim at having expert users who would
> understand this. > > > > I think the
> system should behave in the same (and
> deterministic) > > way, > > > >
> independent of what the user states in
> reservation time. > > > > (Btw - that
> the reservation and provisioning time might
> vary > > does not > > > > make
> it less
> deterministic.) > > > > > > > > > > > >
> With an ADvanced Scheduling function,
> provisioning > > initiation can
> happen > > > > from both the user
> or the provider. > > > > > > > > 2.
> On-Demand Service: In my opinion, Guard-time
> does not > > prevent
> an > > > > On-Demand service as
> specified by Jerry. They
> co-exist. > > > > An on-demand
> service, with Tstart = ASAP can be
> implemented > > very
> easily. > > > > The service starts
> when the "provisioning complete"
> message > > is
> received > > > > by the user. If
> the user does not receive that message,
> it > > continues
> to > > > > wait. > > > > > > > >
> Exactly what I was aiming at - but the
> same logic can apply to > > any
> time > > > > between "NOW" and the
> guard time, or doesn't it? > > > > All
> you need to do, if the start time is reached
> before
> the > > reservation > > > > is
> complete, to wait for the
> latter. > > > > > > > > > > > >
> Does this make more
> sense? > > > > > > > > I will
> answer specifics
> below. > > > > > > > >
> [...] > > > > > > > > What I
> meant is that if that time has passed by the
> time > > the
> provider > > > > NSA gets
> notified of the reservation acceptance
> along > > the path,
> it > > > > should proceed
> directly to
> provisioning. > > > > > > > > In
> advanced reservation, the open question is what
> should a > > domain do
> if > > > > Tstart comes, and it has
> not got a reservation complete
> or > > provision > > > >
> message? Should it delete the connection or
> provision its > > own set
> of > > > > resources? Chin and I
> include this case in the
> error > > recovery
> document > > > > to be published
> soon. > > > > > > > > No, no - simply
> wait for the reservation to complete. Only then
> will > > > > you know if it succeeded
> in the first
> place. > > > > > > > > IMO, the
> provisioning and reservation systems cannot be
> completely > > > > decoupled. The
> provisioning stage should actually never be
> reached > > > > until a reservation is
> complete. It is dependent on the
> outcome > > of the > > > > path
> computation as well as resource reservation.
> Never go
> to > > provisioning > > > >
> before you know you can have the
> resources. > > > > > > > > > > > > > > > >
> You have to do this anyway, to
> protect against the
> guard > > time
> being > > > > set too short. In
> which case you can just as well
> set > > the guard time to
> 0. > > > > > > > > That's just
> common sense, IMO, what it means when
> I > > would ask
> for > > > > immediate > > > >
> circuit provisioning. "Please
> give it to me as soon
> as > > you're able
> to, > > > > I'm
> waiting." > > > > > > > > The
> thing not to forget is that someone can ask for
> a > > circuit not
> only > > > >
> "now", > > > > > > > > I think the
> "now" case is actually, "as soon as possible"
> - > > which is
> the > > > > on-demand case. Then it
> just waits for the right
> message > > from
> the > > > > Provider Agent before
> it knows the connection is
> available > > to be
> used. > > > > > > > > Yes, absolutely
> agree - that's a discussion terminology,
> which > > I'd be > > > > happy
> to change :-) > > > > However, we need
> to be precise on what we mean. An
> "ASAP" > > reservation, > > > >
> from a user's point of view, could mean really
> "any time > > possible,
> starting > > > > from now", i.e. also
> in 2 hours, if the resources will only
> then > > become > > > >
> available. > > > > I am not sure BoD
> does mean that. > > > > Will in such a
> case a BoD reservation be converted into
> a > > scheduled
> one? > > > > > > > > > > > >
> but "a minute from now", which would lead to
> the same > > problem if
> the > > > > time
> to > > > > > > > > A minute from
> now actually becomes a "scheduled
> connection" > > and there
> is > > > > where the problem really
> starts. > > > > > > > > I am sorry I
> have missed large parts of this discussion,
> being > > kept off
> with > > > > other workload. Sorry if I
> am coming back to things which
> might > > be obvious > > > > to
> you by now. > > > > But I do not really
> understand where the problem really
> is. > > > > You mention the
> provisioning system to have to decide what to
> do > > > > if the reservation step is
> not complete - but I think the
> right > > design > > > >
> decision > > > > would be that the
> system should never actually be in such a
> state. > > > > (Sorry, I am falling
> into thinking in terms of state
> machines > > here,
> but > > > > well, > > > >
> that's what I start to believe would be good
> here.) > > > > > > > > Is there other
> reasons? > > > > > > > >
> Cheers, > > > >
> Artur > > > > > > > > > > > > I
> feel we should support both Advanced
> Reservation with > > guard-time
> and > > > > On-demand connection
> service. > > > > > > > >
> Inder > > > > > > > > process
> the reservation is longer than a minute (as
> it > > most
> probably > > > > will
> be > > > > in the next
> future). > > > > So the "now"
> string as in your option 2) would only
> work > > for a
> singular > > > > subset of
> the > > > >
> problem. > > > > > > > >
> Cheers, > > > >
> Artur > > > > > > > > > > > > > > > >
> Guy > > > > > > > > > > > > > > > >
> -----Original
> Message----- > > > > From:
> Artur Barczyk
> [mailto:Artur.Barczyk at cern.ch] > > > >
> Sent: 12 April 2010
> 17:28 > > > > To:
> nsi-wg at ogf.org
> <mailto:nsi-wg at ogf.org> > >
> <mailto:nsi-wg at ogf.org> > > > >
> Subject: Re: [Nsi-wg] Immediate/Advance
> reservation > > (Re: NSI
> conf > > > > call
> minutes) > > > > > > > >
> Hi, > > > > > > > > I think
> guard time is a shaky concept, as who
> can > > tell how long it
> should > > > > be - it
> can/will depend on the number of domains
> the > > circuit > > > >
> contains,
> the > > > > speed of each
> reservation/provisioning system
> as > > well as the load on
> the > > > > system, and
> will be variable over time (hoping
> for > > faster > > > >
> reservation/provisioning > > > >
> reservation/provisioning > > > >
> systems in the
> future). > > > > > > > >
> But: if in step 5, the "wait for start time"
> means > > t_start <=
> t_current, > > > > then
> the > > > > provider will
> immediately pass on to
> provisioning. > > > > What
> needs to be done however is to have
> the > > duration of the
> reservation > > > > reflect
> the time difference between desired
> start > > time and the
> effective > > > >
> one. > > > > > > > > I am
> sure I am missing
> something..? > > > > > > > >
> Cheers, > > > >
> Artur > > > > > > > > > > > > > > > >
> On 04/12/2010 11:12 AM, Guy Roberts
> wrote: > > > >
> Jeroen, > > > > > > > >
> Yes, that is correct. But the mechanism will
> be > > the same
> for > > > > advance
> reservations, just a later start
> time. > > > > > > > >
> Guy > > > > > > > >
> -----Original
> Message----- > > > >
> From: Jeroen van der Ham
> [mailto:vdham at uva.nl] > > > >
> Sent: 12 April 2010
> 08:19 > > > > To: Guy
> Roberts > > > > Cc:
> John Vollbrecht;
> nsi-wg at ogf.org > >
> <mailto:nsi-wg at ogf.org>
> <mailto:nsi-wg at ogf.org> > > > >
> Subject: Re: [Nsi-wg]
> Immediate/Advance > >
> reservation (Re: NSI
> conf > > > > call
> minutes) > > > > > > > >
> To sum this up, this describes a situation
> where > > there is no
> prior > > > >
> reservation and provisioning is
> started > > immediately
> because
> the > > > > startTime
> is meant as a
> "now"? > > > > > > > >
> Jeroen. > > > > > > > > > > > >
> On 09/04/2010 18:56, Guy Roberts
> wrote: > > > >
> John, > > > > > > > >
> My thinking of how it could work is
> as > > follows
> (though the
> details > > > > are
> really part of the protocol
> definition > >
> group's
> work): > > > > > > > >
> StartTime= time when the provisioning
> is > > begun. This
> is the
> only > > > >
> possible meaning for StartTime since we
> have > > no way of
> knowing
> how > > > > long
> the provisioning will take in
> advance > > of the
> provisioning > > > >
> being performed. i.e provisioning
> completion > > time
> is > > > >
> non-deterministic. For consistency as
> an > > asynchronous
> system,
> the > > > >
> completion of provisioning (in-service)
> is > > pushed by
> the NRM to
> the > > > >
> Provider which in turn sends this to
> the > > Requestor
> as a
> notification. > > > > > > > > > > > >
> Locally initiated
> provisioning: > > > >
> 1. The Requester NSA creates a request
> with > > a start
> time > > > >
> (StartTime). StartTime= NSAs current
> time > > +
> Requester guard
> time. > > > > Eg
> 12:00pm + 5 minutes =
> 12:05pm. > > > > 2.
> Provider validates the start time
> as > > being at
> least the
> provider > > > >
> guard time away from now. (note
> requester > > and
> provider guard
> times > > > > could
> be a little different to allow
> for > >
> transmission delay of
> request) > > > > 3.
> Provider begins the reservation
> process > >
> (12:01pm) > > > >
> 4. Provider completes the reservation
> (12:02pm) > > > >
> 5. Provider waits for the startTime
> (12:05pm) > > > >
> 6. Provider starts provisioning
> locally > >
> (12:05pm) > > > >
> 7. Provider waits for confirmation
> of > > provisioning
> from NRM
> (12:06pm) > > > >
> 8. Provider sends a notification to
> the > > requestor
> NSA to
> notify > > > > that
> the connection is in-service
> (12:06pm) > > > > > > > >
> Provisioning signalled by
> Requester: > > > >
> 1. The Requester NSA creates a request
> with > > a start
> time > > > >
> (StartTime). StartTime= NSAs current
> time > > +
> Requester guard
> time. > > > > Eg
> 12:00pm + 5 minutes =
> 12:05pm. > > > > 2.
> Provider validates the start time
> as > > being at
> least the
> provider > > > >
> guard time away from now. (note
> requester > > and
> provider guard
> times > > > > could
> be a little different to allow
> for > >
> transmission delay of
> request) > > > > 3.
> Provider begins the reservation
> process > >
> (12:01pm) > > > >
> 4. Provider completes the reservation
> (12:02pm) > > > >
> 5. Provider waits for the startTime
> (12:05pm) > > > >
> 6. Provider waits for the signal
> to > > provision
> (12:10pm) > > > >
> 7. Provider initiates provisioning of
> the > > Connection
> (12:10pm) > > > >
> 7. Provider waits for confirmation
> of > > provisioning
> from NRM
> (12:11pm) > > > >
> 8. Provider sends a notification to
> the > > requestor
> NSA to
> notify > > > > that
> the connection is in-service
> (12:11pm) > > > > > > > > > > > >
> Guy > > > > > > > > > > > > > > >
> Guy > > > > > > > > > > > > > > > >
> -----Original
> Message----- > > > >
> From: John Vollbrecht
> [mailto:jrv at internet2.edu] > > > >
> Sent: 09 April 2010
> 17:28 > > > > To:
> Guy
> Roberts > > > > Cc:
> John Vollbrecht; Tomohiro Kudoh;
> Jeroen > > van der
> Ham; > > > >
> nsi-wg at ogf.org
> <mailto:nsi-wg at ogf.org> > >
> <mailto:nsi-wg at ogf.org> > > > >
> Subject: Re: [Nsi-wg]
> Immediate/Advance > >
> reservation (Re: NSI
> conf > > > > call
> minutes) > > > > > > > >
> I am still a bit confused. Perhaps
> someone > > could
> do a timing
> diagram > > > >
> like the one Tomohiro did a while ago
> when > > we were
> discussing 2
> phase > > > >
> commits. > > > > > > > >
> I will try to explain my
> confusion. My > >
> understanding has been
> that > > > >
> we > > > > agreed
> that provisioning would never be
> done > > without
> prior > > > >
> reservation. So it would seem that
> the > > question
> being discussed
> is > > > > "what is
> the time being requested in
> a > > reservation".
> If
> the > > > >
> reservation succeeds then provisioning
> can > >
> happen. > > > > > > > >
> It seems to me one question is how to
> define > > the
> start time
> being > > > >
> requested. The options seem to be that
> is > > is either 1)
> the time
> the > > > > circuit
> is actually provisioned and ready
> to > > use or 2)
> the time
> that > > > >
> provisioning of the circuit starts. In
> one > > case the
> previous > > > >
> connection may terminate sooner by the
> guard > > time and
> in the
> latter > > > >
> it > > > > may
> start later by the guard time. If
> it > > is (1) then
> a
> connection > > > >
> scheduled for now must have been started
> at > > [now -
> (start
> time)]. > > > > > > > >
> A second question is whether is is
> possible > > to
> request a
> connection > > > >
> that starts "now". This implies reserving
> a > > connection
> and > > > >
> initiating > > > >
> it as soon as it is reserved. Assume
> that > > start time
> is
> when > > > >
> provisioning a circuit starts (case
> 2 > > above). It
> seems that
> main > > > > issue
> with this is whether the time
> to > > reserve a
> connection is
> longer > > > > than
> the requestor is willing to
> wait. The > > time
> it takes depends
> on > > > > how many
> NSAs are "chained" to satisfy
> the > > request and
> how long
> each > > > > NSA
> takes to reserve the
> connection. This > >
> time is
> "authorization > > > >
> time" not guard time as I understand
> it. > > > > > > > >
> There is another issue with
> defining > >
> authorization as "now"
> instead > > > >
> of > > > > a
> specific time. The problem is that
> each > > NSA in a
> chain will
> think > > > >
> authorization happens at a
> slightly > >
> different time. I am not
> sure > > > >
> how > > > >
> important this is - it doesn't seem
> too > > important
> to me,
> but > > > > perhaps
> I > > > > am
> wrong. If provisioning starts after
> the > > reservation
> is
> complete, > > > >
> then everything should be reserved, if at
> a > > slightly
> different
> time. > > > >
> ---------------------------------- > > > > > > >
> > I think Guy is
> suggesting that start time
> is > > when
> provisioning
> starts > > > >
> (case 2) above. That seems simplest to
> me. > > > > I am
> not sure the provisioning time
> is > > important,
> and if not I
> would > > > > think
> it good to include "immediate"
> reservation > > > > > > > >
> John > > > > > > > > > > > >
> On Apr 9, 2010, at 11:15 AM,
> Guy Roberts
> wrote: > > > > > > > >
> Tomohiro, > > > > > > > >
> In this case, only some
> parts
> of > >
> inter-network connection will
> be > > > >
> provisioned. > > > > > > > >
> Right, I forgot about this reason
> - it > > is a
> good point. Again,
> I > > > > think
> we are not complicating things
> too > > much if
> we have a rule
> that > > > >
> the Requester NSA cannot send a
> start > > time
> sooner than
> now+guardtime. > > > > > > > >
> I think we can solve the chain
> issue
> by > > not
> forcing any value
> for > > > > the
> guard time. This can be a
> policy > >
> decision to suit the
> service > > > >
> type, equipment and number of
> networks > >
> involved. > > > > > > > >
> Guy > > > > > > > >
> -----Original
> Message----- > > > >
> From: Tomohiro
> Kudoh > >
> [mailto:t.kudoh at aist.go.jp] > > > >
> Sent: 09 April 2010
> 09:04 > > > >
> To: Jeroen van der
> Ham > > > > Cc:
> nsi-wg at ogf.org > >
> <mailto:nsi-wg at ogf.org> > >
> <mailto:nsi-wg at ogf.org> > > > >
> <mailto:nsi-wg at ogf.org> > > > >
> Subject: Re: [Nsi-wg]
> Immediate/Advance > >
> reservation (Re: NSI
> conf > > > >
> call
> minutes) > > > > > > > >
> Hi
> Jeroen, > > > > > > > >
> There is a problem for
> inter-network > >
> connection. During
> the > > > >
> discussions > > > >
> in some calls, the problem
> of > >
> synchronizing networks (managed
> by > > > >
> different NSAs) was
> discussed. > > > > > > > >
> If you use the "now" type request
> for > >
> inter-network
> connection > > > >
> (without > > > >
> complicated coordination), the
> actual > >
> provisioning time of
> networks > > > >
> may > > > >
> be different. Moreover, some
> networks > >
> may provision resources
> before > > > >
> some other networks reply to
> the > >
> request, and such networks might
> deny > > > >
> the request. In this case, only
> some > > parts
> of inter-network
> connection > > > >
> will be
> provisioned. > > > > > > > >
> The guard time is one of the
> simple > >
> solutions to solve this problem.
> I > > > >
> understand there can be multiple ways
> to > > cope
> with this, but all
> of > > > >
> them > > > >
> will introduce some complication to
> some > > part
> (note that we
> decided > > > >
> not > > > > to
> use 2PC for the v1.0). This is
> a > > design
> choice
> matter. > > > > > > > >
> Regards, > > > > > > > >
> Tomohiro > > > > > > > > > >
> Tomohiro > > > > > > > > > > > >
> On Thu, 08 Apr 2010 09:27:59
> +0200 > > > >
> Jeroen van der Ham
> <vdham at uva.nl > >
> <mailto:vdham at uva.nl> > >
> <mailto:vdham at uva.nl>>
> wrote: > > > > > > > >
> On 07/04/2010 15:02, Tomohiro
> Kudoh > >
> wrote: > > > >
> If a requester wants
> resources > >
> to be provisioned as soon
> as > > > >
> possible,
> it > > > >
> can set the start time
> parameter > >
> in a advance request
> to: > > > >
> (current time + guard time +
> a > >
> certain time required for
> message > > > >
> delivery). > > > > > > > >
> In this way,
> immediate > >
> provisioning can be requested
> by > >
> an
> advance > > > >
> reservation
> request. > > > > > > > >
> The procedure above seems
> overly > >
> complicated and if I really
> am > > > >
> pressed > > > >
> for time, and I miscalculate
> the > >
> (current time + guard time
> + > > > >
> delivery > > > >
> time) by a few seconds. Denying
> the > >
> request means that I have to
> do > > > >
> it > > > >
> all over again, making me even
> more > >
> pressed for
> time. > > > > > > > >
> Why not keep things simple
> and > >
> always interpret a start time in
> the > > > >
> past > > > >
> as "now" ? (provided the end-time
> is > > in
> the future
> too) > > > >
> Would there be any
> problems > >
> associated with
> that? > > > > > > > >
> Jeroen. > > > > > > > > > > > > > > >
> Jeroen. > > > > > > > > > > > > > > > > >
> _______________________________________________
> > > > > nsi-wg
> mailing
> list > > > >
> nsi-wg at ogf.org
> <mailto:nsi-wg at ogf.org> > >
> <mailto:nsi-wg at ogf.org> > > > >
> http://www.ogf.org/mailman/listinfo/nsi-wg
> http://www.ogf.org/mailman/listinfo/nsi-wg > > >
> > >
> _______________________________________________
> > > > > nsi-wg
> mailing
> list > > > >
> nsi-wg at ogf.org
> <mailto:nsi-wg at ogf.org> > >
> <mailto:nsi-wg at ogf.org> > > > >
> http://www.ogf.org/mailman/listinfo/nsi-wg
> http://www.ogf.org/mailman/listinfo/nsi-wg > > >
> > > > > >
> _______________________________________________
> > > > > nsi-wg
> mailing
> list > > > >
> nsi-wg at ogf.org
> <mailto:nsi-wg at ogf.org> > >
> <mailto:nsi-wg at ogf.org> > > > >
> http://www.ogf.org/mailman/listinfo/nsi-wg
> http://www.ogf.org/mailman/listinfo/nsi-wg > > >
> > > > > > > > > > > > > >
> _______________________________________________
> _______________________________________________
> > > > > nsi-wg mailing
> list > > > >
> nsi-wg at ogf.org
> <mailto:nsi-wg at ogf.org> > >
> <mailto:nsi-wg at ogf.org> > > > >
> http://www.ogf.org/mailman/listinfo/nsi-wg
> http://www.ogf.org/mailman/listinfo/nsi-wg > > >
> > > > > > > > > > -- > > > >
> Dr Artur
> Barczyk > > > > California
> Institute of
> Technology > > > > c/o CERN,
> 1211 Geneve 23,
> Switzerland > > > > Tel: +41
> 22
> 7675801 > > > >
> _______________________________________________
> > > > > nsi-wg mailing
> list > > > > nsi-wg at ogf.org
> <mailto:nsi-wg at ogf.org> > >
> <mailto:nsi-wg at ogf.org> > > > >
> http://www.ogf.org/mailman/listinfo/nsi-wg > > >
> > > > > > --- > > > >
> Inder Monga
> http://100gbs.lbl.gov > > > >
> imonga at es.net <mailto:imonga at es.net>
> <mailto:imonga at es.net> > >
> http://www.es.net > > > > (510) 499
> 8065 (c) > > > > (510) 486 6531
> (o) > > > > > > > > > > > > -- > > > >
> Dr Artur
> Barczyk > > > > California Institute of
> Technology > > > > c/o CERN, 1211
> Geneve 23,
> Switzerland > > > > Tel: +41 22
> 7675801 > > > >
> _______________________________________________
> > > > > nsi-wg mailing
> list > > > > nsi-wg at ogf.org
> <mailto:nsi-wg at ogf.org> > > > >
> http://www.ogf.org/mailman/listinfo/nsi-wg > > >
> > > > > > > > -- > > Dr Artur Barczyk > >
> California Institute of Technology > > c/o
> CERN, 1211 Geneve 23, Switzerland > >
> Tel: +41 22 7675801 > > > > > > > >
> --- > > > > Inder Monga > >
> http://100gbs.lbl.gov > > imonga at es.net
> <mailto:imonga at es.net> > >
> http://www.es.net > > (510) 499 8065 (c) > >
> (510) 486 6531 (o) > > > > > > > > -- > Dr
> Artur Barczyk > California Institute of
> Technology > c/o CERN, 1211 Geneve 23,
> Switzerland > Tel: +41 22 7675801
> _______________________________________________
> nsi-wg mailing list nsi-wg at ogf.org http://www.ogf.org/mailman/listinfo/nsi-wg
Joe Mambretti,
Director tel 312.503.0735
International Center for Advanced Internet Research fax 312.503.0745
750 North Lake Shore Drive, Suite 600 www.icair.org
Northwestern University, Chicago, Illinois 60611
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