[Nsi-wg] Immediate/Advance reservation (Re: NSI conf call minutes)
Joe Mambretti
j-mambretti at northwestern.edu
Wed Apr 14 07:23:10 CDT 2010
I agree with your comments. These issues are
design decisions. The protocol can be designed
only as a request for resources, completely
agnostic to any type of timing, including a
time-to-live flag for the signal. Or it can be
designed to include some type of "promised"
service. Note that when you make a call, you have
an high degree of expectation of completing the
connection. However, sometimes, you receive a
busy signal, a message indicating that "all
circuits are busy" or the line is dropped. There
are no absolutes in communications. One
consideration with this protocol is that in
general in the near term (next 3 years) these
requests will be made for large scale resources
that will be required for extended periods
(hours, days, perhaps week). In these types of
cases an initial delay in set up is generally expected and tolerated.
At 06:58 AM 4/14/2010, Jerry Sobieski wrote:
>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
>>> <mailto:radek.krzywania at man.poznan.pl>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:
>>> <mailto:radek.krzywania at man.poznan.pl>radek.krzywania at man.poznan.pl
>>> > Cc: 'Inder Monga';
>>> <mailto:nsi-wg at ogf.org>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 > > > >
>>> <mailto:radek.krzywania at man.poznan.pl>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:*
>>> <mailto:radek.krzywania at man.poznan.pl>radek.krzywania at man.poznan.pl;
>>> <mailto:nsi-wg at ogf.org>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 > > > >
>>> <mailto:radek.krzywania at man.poznan.pl>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:
>>> <mailto:nsi-wg-bounces at ogf.org>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:
>>> <mailto:nsi-wg at ogf.org>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 > > > > > > > > > > > > > > >
>>> Guy > > > > > > > > > > > > > > > >
>>> -----Original
>>> Message----- > > > >
>>> From: Artur Barczyk [
>>> mailto:Artur.Barczyk at cern.ch] > > > >
>>> Sent: 12 April 2010
>>> 17:28 > > > > To:
>>> <mailto:nsi-wg at ogf.org>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;
>>> <mailto:nsi-wg at ogf.org>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; > > > >
>>> <mailto:nsi-wg at ogf.org>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:
>>> <mailto:nsi-wg at ogf.org>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
>>> <mailto:vdham at uva.nl><vdham at uva.nl > >
>>> <mailto: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 > > > >
>>> <mailto:nsi-wg at ogf.org>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 > > > >
>>> <mailto:nsi-wg at ogf.org>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 > > > >
>>> <mailto:nsi-wg at ogf.org>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 > > > >
>>> <mailto:nsi-wg at ogf.org>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 > > > >
>>> <mailto:nsi-wg at ogf.org>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 > >
>>> > > > > > > --- > > > >
>>> Inder Monga
>>> http://100gbs.lbl.gov > > > >
>>> <mailto:imonga at es.net>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 > > > >
>>> <mailto:nsi-wg at ogf.org>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 > >
>>> <mailto:imonga at es.net>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
>>> <mailto:nsi-wg at ogf.org>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
>>
>>
>>
>>
>>_______________________________________________
>>nsi-wg mailing list
>><mailto:nsi-wg at ogf.org>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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