Hi,
Please correct me if I am missing something, I am simply adding the PCE
response times of all the PCEs interrogated along the way.
If the relaying is done in parallel like in :
--> PCE31--> PCE32--> PCE33
/
PCE1---->PCE2 ----> PCE41--> PCE42--> PCE43--> PCE44
\
-->PCE51-> PCE52
assuming in this example that all PCEs have the same response time, then the
total response time will be the longest one, in this case that of :
PCE1---->PCE2 ----> PCE41--> PCE42--> PCE43--> PCE44
= RESPONSE TIMES OF (PCE2 + PCE41+PCE42+ PCE43+ PCE44)
Cheers,
Meral
Selon Eric Gray <[EMAIL PROTECTED]>:
> 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
> > >> >
> > >>
> > >>
> > >>
> > >
> > >
> >
> >
> > _______________________________________________
> > Pce mailing list
> > [email protected]
> > https://www.ietf.org/mailman/listinfo/pce
> >
>
>
_______________________________________________
Pce mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/pce
