[Nsi-wg] Immediate/Advance reservation (Re: NSI conf call minutes)
Radek Krzywania
radek.krzywania at man.poznan.pl
Tue Apr 13 08:42:10 CDT 2010
Hi,
Indeed, I forgot about NTP. But still my opinion is that we are unable to assure time precision at the level of seconds. Minutes are far more probable.
Regarding race conditions, it's not the role of the protocol to prevent it. 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
> >
> > 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
> >
> >
> >
> >
> >
> >
> >
> > -----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>
> >
> > 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
> >
> >
> >
> >
> >
> > 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.
> >
> >
> >
> >
> >
> >
> >
> >
> _______________________________________________
> >
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> >
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> > <mailto:nsi-wg at ogf.org>
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> >
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> _______________________________________________
> >
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> >
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> >
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> >
> >
> >
> >
> > _______________________________________________
> >
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> >
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> >
> > 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
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