[Nsi-wg] Immediate/Advance reservation (Re: NSI conf call minutes)
Jerry Sobieski
jerry at nordu.net
Wed Apr 14 06:58:41 CDT 2010
Well said Joe. Very good points, particularly about the similarities
of advanced vs immediate. I agree completely.
But we do run into some real protocol issues since previous protocols
did not deal with a time constraints. In order to support the time
constraint we need to understand what the "promise" is to the user
within the NSI: If the promise is to provide a connection with certain
characteristics (one being start time to end time) we need to anticipate
the timing issues associated with resource reservation and provisioning
as we change states.
There are easy ways to punt the issue: For instance, we can state that
provisioning begins at the start time. This is simple from the
protocol and scheduling issues, but it means the user has no guarrantee
of when the connection will actually be usable!... So I don't think in
all fairness this is an appropriate way to handle it...we need to take
Jeff's comments to heart: What does the user expect from these service
interfaces? IMO, the start time should be the "In-Service start time",
and if we need a "Provisioning start time" parameter someplace, then we
figure out how to bound it authoritatively and do that.
Jerry
Joe Mambretti wrote:
> 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 <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 <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
>> <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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>> > nsi-wg at ogf.org <
>> mailto:nsi-wg at ogf.org> > > <
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>> http://www.ogf.org/mailman/listinfo/nsi-wg > > > > > > >
>> >
>> _______________________________________________ > > >
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>> > > < mailto:nsi-wg at ogf.org> > > >
>> >
>> http://www.ogf.org/mailman/listinfo/nsi-wg > > > > > > > > > > > > >
>> > > >
>> _______________________________________________ > > >
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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> > > <
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>> http://www.ogf.org/mailman/listinfo/nsi-wg > > > > > > >
>> > --- > > > > Inder Monga
>> http://100gbs.lbl.gov <http://100gbs.lbl.gov/> > > > >
>> imonga at es.net < mailto:imonga at es.net> < mailto:imonga at es.net> >
>> > http://www.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
>> <http://100gbs.lbl.gov/> > > imonga at es.net < mailto:imonga at es.net> >
>> > http://www.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
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