Re: [Pce] Comment on draft-ietf-pce-pcecp-interarea-reqs-00.txt

[Zhang Renhai <[e-mail]>]

Hi, Jean-Philippe

See inline.

----- Original Message ----- 
From: "JP Vasseur" <[e-mail]>
To: "zhangrenhai 18605" <[e-mail]>
Cc: "LE ROUX Jean-Louis RD-CORE-LAN" <[e-mail]>; <[e-mail]>
Sent: Friday, January 13, 2006 9:52 PM
Subject: Re: [Pce] Comment on draft-ietf-pce-pcecp-interarea-reqs-00.txt


> Hi,
> 
> On Jan 12, 2006, at 10:40 PM, zhangrenhai 18605 wrote:
> 
> > Hi, JP
> >
> > Sorry for seeing your reply so late.
> > Thanks, see inline.
> >
> > ----- Original Message -----
> > From: JP Vasseur <[e-mail]>
> > Date: Thursday, January 5, 2006 3:07 am
> > Subject: Re: [Pce] Comment on draft-ietf-pce-pcecp-interarea- 
> > reqs-00.txt
> >
> >> Hi ,
> >>
> >> On Dec 28, 2005, at 2:03 AM, Zhang Renhai wrote:
> >>
> >>> Hi, Jean-Louis
> >>>
> >>>  I have some comment on the draft draft-ietf-pce-pcecp-interarea-
> >>
> >>> reqs-00.txt
> >>>
> >>>  In section 7.11.1, In case of network failure, jittering will
> >> be
> >>> used to avoid
> >>> simultaneous requests sent to one PCE. Could more consideration
> >> be
> >>> given here to
> >>> the preemptment, becouse the jittering timeout is stochastic,
> >> some
> >>> lower request
> >>> may be served before a higher request and the path may be
> >>> calculated differently.
> >>> which may increase the probability of a preemptment.
> >>>
> >>
> >> The decision on the PCC request scheduling is out of the scope of
> >> this ID. Note that the point that you mentioned also applies to
> >> the
> >> located-PCE case.
> > I am not sure what scope this point belongs to. I just considered  
> > more about what
> > has been mentioned in the draft.
> > Is this consideration important anough to be added somewhere?
> 
> You're very welcome to discuss the topic on the list 
[ZRH](Can I cut your words so?) Thanks !

but PCC request  
> request scheduling are not standardized.
> 
> >>
> >>>
> >>>  I have always been thinking a question: if a PCC will not
> >> perform
> >>> the CSPF
> >>> computation, why does it still maintain the TEDB any longer?
> >> which
> >>> may consume
> >>> a lot of memory and CPU of a LSR.This question dost not aid at
> >> this
> >>> draft.
> >>>
> >>
> >> Because
> >> (1) The PCE may decide to use a remote PCE for some LSPs and not
> >> for
> >> others (for instance, inter versus intra-domain)
> >> (2) The PCE may decide to always use a PCE and fall back to local
> >> path computation or loose hop routing under specific conditions
> > Agree, I just want to be convinced if some routers acting as a pure  
> > PCC
> > (no longer perform path computation)can save some CPU and memory so
> > there could be a lower requirement on capability to these routers
> > in PCE-based environment.Maybe this is a benefit to PCE Architecture.
> 
> Sure, this is an option already described in the draft.
> 
> >>
> >>>  In inter-area environment,sometimes, a PCC may wish to get as
> >> many
> >>> paths as possible,
> >>> for all kinds of purpose,so could the PCC send the request to
> >> more
> >>> than one PCEs?
> >>>
> >>
> >> Yes, although this would clearly be very sub-optimal ....
> > I am not sure your point, could you please expand your explanation  
> > any more?
> > In my opinion, a ABR acting as a PCE usually can not have a full AS- 
> > scope information of TED.
> > so it may return a sub-optimal compuation result compared to some
> > latent path which can be returned by other ABR linked to a different
> > area. I know this can be solved by a ABR through sending the  
> > request to multiple
> > ABR in a area, otherwise, how to solve this problem?
> 
> Yes stay tuned ... I'll resurrect soon a draft that used to be  
> discussed in CCAMP detailing these aspects.
[ZRH]If possible, I can join you.

> 
> Thanks.
> 
> JP.
> 
> >
> >
> > Thanks,
> > Zhang
> >
> >>
> >> JP.
> >>
> >>> Regards,
> >>> Zhang
> >>> _______________________________________________
> >>> Pce mailing list
> >>> [e-mail]
> >>> https://www1.ietf.org/mailman/listinfo/pce
> >>
> >>

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