[Nsi-wg] Immediate/Advance reservation (Re: NSI conf call minutes)
Jeff W.Boote
boote at internet2.edu
Tue Apr 13 11:11:40 CDT 2010
I'd like to encourage everyone to consider this more from the client
perspective instead of from the provisioning perspective... The reason
to make a circuit reservation is not in isolation. The client is doing
this because they want to make some kind of data transfer that
certainly involves other resources that also need to be scheduled.
In that context, I think the required semantics become more clear.
Give the two-phase commit cycle that is happening anyway, I would
expect something like:
1) Reservation request is for a given time T, and duration D. The
semantics of this request from the client perspective should be, I
would like to use the circuit at time T. (After all, the client is
trying to reserve other resources to use the circuit at that same time.)
2) The provider determines how 'close' to time T they can actually
provision the circuit (after requesting down-stream if chaining). The
response should be: you can have reservation time T+delta. (Where
delta MUST be as small as the provider can make it.) If T=='now' that
would likely produce a greater 'delta' than a T in the more distant
future.
When developing the actual protocol, it may also be necessary to also
return another time indicating how quickly the client must initiate
the second phase of the commit or the reservation automatically
nullifies...
jeff
On Apr 13, 2010, at 8:51 AM, John Vollbrecht wrote:
>
> On Apr 13, 2010, at 9:10 AM, Gigi Karmous-Edwards wrote:
>
>> Artur,
>>
>> I thought that we had agreed on the two-phase-commit - like
>> behavior .... where all reservation responses must be complete
>> prior to and provisioning on any part of the path?
>>
> I think that the two phase commit could be just on each part of the
> path if notification is used to identify when the whole path is
> available. This would allow each segment to be provisioned
> independently. In the "now" case a segment could provision as soon
> as its reservation was complete. It would respond with reservation
> complete, then when provisioning is done it would notify
> provisioning done. This keeps reservation and provisioning
> orthogonal.
>
>> Gigi
>>
>> 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 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] On
>>>>> Behalf Of
>>>>> Artur Barczyk
>>>>> Sent: Tuesday, April 13, 2010 10:11 AM
>>>>> To: Inder Monga
>>>>> Cc: 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>
>>>>>>>> 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>
>>>>>>>>> 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>
>>>>>>>>>> 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>
>>>>>>>>>>> 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>>
>>>>>>>>>>> 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.
>>>>>>>>>>>>
>>>>>>>>>>> _______________________________________________
>>>>>>>>>>> nsi-wg mailing list
>>>>>>>>>>> nsi-wg at ogf.org <mailto:nsi-wg at ogf.org>
>>>>>>>>>>> http://www.ogf.org/mailman/listinfo/nsi-wg
>>>>>>>>>>> _______________________________________________
>>>>>>>>>>> nsi-wg mailing list
>>>>>>>>>>> nsi-wg at ogf.org <mailto:nsi-wg at ogf.org>
>>>>>>>>>>> http://www.ogf.org/mailman/listinfo/nsi-wg
>>>>>>>>>>>
>>>>>>>>>> _______________________________________________
>>>>>>>>>> nsi-wg mailing list
>>>>>>>>>> nsi-wg at ogf.org <mailto:nsi-wg at ogf.org>
>>>>>>>>>> http://www.ogf.org/mailman/listinfo/nsi-wg
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>> _______________________________________________
>>>>>>>>> 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
>>>>>>> _______________________________________________
>>>>>>> nsi-wg mailing list
>>>>>>> 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> http://www.es.net
>>>>>> (510) 499 8065 (c)
>>>>>> (510) 486 6531 (o)
>>>>>>
>>>>>>
>>>>> --
>>>>> Dr Artur Barczyk
>>>>> California Institute of Technology
>>>>> c/o CERN, 1211 Geneve 23, Switzerland
>>>>> Tel: +41 22 7675801
>>>>> _______________________________________________
>>>>> nsi-wg mailing list
>>>>> nsi-wg at ogf.org
>>>>> http://www.ogf.org/mailman/listinfo/nsi-wg
>>>>>
>>>
>>>
>> _______________________________________________
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