Adrian,
You would not take into consideration the potential for
relayed communication times in the distributed PCE case?
--
Eric Gray
Principal Engineer
Ericsson
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
> Behalf Of Adrian Farrel
> Sent: Tuesday, August 05, 2008 1:21 PM
> To: Meral Shirazipour
> Cc: [email protected]
> Subject: Re: [Pce] PCE computation time
>
> I think you might predict PCEP communication time as...
>
> TCP connection setup
> PCEP session establishment
> PCEP request/response
>
> You might approximate this with a web browser or any other TCP-based
> application.
>
> FWIW I would expect a simple CSPF to be computed in a few
> hundred ms at
> absolute most (but probably in a less than a few tens of ms) and
> communication time to be of the order of one second tops. YMMV.
>
> Cheers,
> Adrian
> ----- Original Message -----
> From: "Meral Shirazipour" <[EMAIL PROTECTED]>
> To: "Adrian Farrel" <[EMAIL PROTECTED]>
> Cc: <[email protected]>
> Sent: Tuesday, August 05, 2008 5:44 PM
> Subject: Re: [Pce] PCE computation time
>
>
> > Hi Adrian,
> > For the PCE computation time, I was considering all that
> you mentioned
> > except
> > the compiler efficiency/software implementation dependencies.
> >
> > Also when you say:
> >> In general,
> >> for this type of computation, we observe that a remote
> PCEP communication
> >> takes far more time than the computation. (Times may vary
> according to
> >> the
> >> pre-existence of the PCEP session.)
> >
> > are we talking "worse case" PCEP communication time in the order of
> > seconds?
> > minutes? ..?
> >
> > I am assuming that:
> > PCE response time = PCEP communication time + PCE computation time
> >
> > Then the total response time is some sort of a summation of
> the response
> > times
> > of all the PCEs in the PCE chain.
> >
> > Any further comments would be greatly apperciated. I am
> trying to come up
> > with
> > "typical/realistic" PCE response times for the single LSP
> computation
> > case. I
> > do understand that this time could greatly vary depending
> on the criterias
> > you
> > mentioned (CPU power, etc.), but just knowing if in practice it is
> > typically in
> > the orders of seconds, minutes, hours would be of great help to me.
> >
> > many thanks,
> > Meral
> >
> >> Now then, Meral,
> >>
> >> I think computation times *might* be dependent on CPU
> power, loading,
> >> compiler efficiency, software implementation, algorithm
> choice, network
> >> complexity, etc.
> >>
> >> Some observations suggest that computation for single LSPs
> with normal
> >> constraints can be achieved using CSPF and there are
> studies recording
> >> the
> >> number of logical steps needed to perform such a
> computation. In general,
> >> for this type of computation, we observe that a remote
> PCEP communication
> >> takes far more time than the computation. (Times may vary
> according to
> >> the
> >> pre-existence of the PCEP session.)
> >>
> >> Other observations note that some computation problems are
> quite hard and
> >> need a few more cycles. In these cases, given the low
> power of CPUs on
> >> NEs,
> >> the communication time may be less significant.
> >>
> >> Cheers,
> >> Adrian
> >> ----- Original Message -----
> >> From: "Meral Shirazipour" <[EMAIL PROTECTED]>
> >> To: <[email protected]>
> >> Sent: Tuesday, August 05, 2008 12:24 AM
> >> Subject: [Pce] PCE computation time
> >
> >
> >> > Hi,
> >> > Does anyone have actual values for the min/average/max PCE
> >> > computation
> >> > times
> >> > in a real network?
> >> > I remember that the issue was discussed for the monitoring draft.
> >> >
> >> >
> >> > Thanks,
> >> > Meral
> >> >
> >> >
> >> > _______________________________________________
> >> > Pce mailing list
> >> > [email protected]
> >> > https://www.ietf.org/mailman/listinfo/pce
> >> >
> >>
> >>
> >>
> >
> >
>
>
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