Re: [Pce] I-D Action:draft-bao-pce-pre-configured-routing-00.txt

["Margaria, Cyril (NSN - DE/Munich)" <cyril.margaria at nsn.com>]

Hi, 

I think the term pre-configured route is a bit misleading, I understand
the scenario as the PCC ask for 3 routes, the first one will be
signaled, the 2 other kept in case a failure happens on the first route.

If I am not misunderstood this can be achieved by using the svec with 3
time the same endpoints and bandwidth. 

Regarding the indication that a route has changed, the PCE could send a
PCRep with RRO (not allowed in rfc5440) and ERO containing the new Path,
but what should be the request id of the PCRep?

In addition the PCC could also be aware that the route failed and
request a new Path computation for the failed path. 

In this context I do not see the need to have a new flag in the RP
object for this use case.


Best Regards
Cyril Margaria

-----Original Message-----
From: pce-bounces at ietf.org [mailto:pce-bounces at ietf.org] On Behalf Of
ext Adrian Farrel
Sent: Monday, October 19, 2009 1:29 PM
To: Bao.Yuanlin at zte.com.cn; fu.xihua at zte.com.cn; xie.gang at zte.com.cn
Cc: pce at ietf.org
Subject: Re: [Pce] I-D
Action:draft-bao-pce-pre-configured-routing-00.txt

While this is a reasonably well-written draft, I don't see that it adds 
anything to what we already have in the core RFCs.

In section 4.3 you have...

   There are two options
   for PCE to send pre-configured route as follows:
   PCRep is used to respond route computation result naturally.  If it
   is used to send pre-configured route, a new flag SHOULD be defined to
   indicate the route carried is pre-configured route.

Two questions:
1. What is the other option? You only list one option.
2. Why do you need a flag to indicate that a route is pre-
   configured? Why does the PCC care how the route was
   derived?

You slighlty answer question 2, in section 5.1 where you say...

   When PCC requests pre-configured route

...but why would the PCC ask for a pre-configured route? It just wants a

route. If there is a policy to be applied by the PCE in selection of the

route, this should be indicated using the normal policy functions. If
there 
is an objective function/algorithm to be applied in selecting the route,

this should be indicated using the OF object.

So I think that you don't need the pre-configured route flag.

Cheers,
Adrian 

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