Subject: RSVP-TE question

From: "Parmar, Pankaj N" <[email-masked]>
Date: Fri, 25 May 2001 16:19:14 -0700

I need some clarification on the role of PATH and RESV messages while
setting up an LSP with QoS requirements. The draft talks about use of PATH
messages for verification of available bandwidth at a particular priority
and possible pre-emption of lower priority reservations. Could the PATH
message be used to hold QoS resources as well ? If yes, then what role does
RESV message play (in regards to setting up QoS) ? If no, when do QoS
resources actually get reserved ?

Thanks,

-Pankaj

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From: Khuzema Pithewan <[email-masked]>
Date: Sat, 26 May 2001 14:58:22 +0530

I think, while propagating PATH messages RSVP-TE ensures the required
resources will be available..thats why it queries at each node if required
resources are available or not. If not available it send back the PATHERR
with error code "admission control failure" and error value "02", while
actual resources are reserved at the time when node receives RESV message.

Khuzema. 

> ----------
> From: 	Parmar, Pankaj N
> Sent: 	Saturday, May 26, 2001 4:49 AM
> To: 	[email-masked]'
> Subject: 	RSVP-TE question
>

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From: Navin Kumar Agrawal <[email-masked]>
Date: Sat, 26 May 2001 19:14:05 +0100 (BST)

> resources actually get reserved ?

Answer is no, if you are asking a question. Whereas, 
I would agree w/ you, if this was a suggestion.

NKA

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From: "Martin, Christian" <[email-masked]>
Date: Sun, 27 May 2001 18:41:43 -0400

> actual resources are reserved at the time when node receives 

This does nothing to control the realized QoS, as a misbehaving flow could
easily exceed its reserved QoS.  Hard QoS is a false deity in RSVP-TE over
IP networks as of today.

 -chris

> > message be used to hold QoS resources as well ? If yes, 
> then what role
> > does

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From: Navin Kumar Agrawal <[email-masked]>
Date: Sat, 26 May 2001 02:21:19 +0100 (BST)

READ ON....

> and possible pre-emption of lower priority
> reservations. 

> Could the PATH message be used to hold QoS 
> resources as well ?

My answer is no, if this is a question. And I would
agree with you, if this is a not a question but a
new idea over the existing protocol.

> If yes, then what role does RESV message play 
> (in regards to setting up QoS) ?

> If no, when do QoS resources actually get reserved ?
> 
> Thanks,
> 
> -Pankaj