Re: A quick question on http://www.ietf.org/internet-drafts/draft-ietf-ccamp-gmpls-recovery-e2e-signaling-03.txt

[Huub van Helvoort <hhelvoort@chello.nl>]

Hi Dimitri,

You wrote:

> zafar, i am not sure to fully understand your question
>
> the O-bit is used for 1+1 and 1:1 protection scheme such as to have an 
> indication when a protecting LSP is carrying the "normal" traffic after 
> protection switching (so it applies only in case of 1+1 LSP 
> uni-/bidirectional protection or 1:1 LSP protection)

[hvh] in 1+1 "normal" traffic is bridged to both working and
      protecting LSP, at the receiving end a switch is used to
      select either the working or protecting LSP.
      In this case the O-bit you describe above has no meaning.

      In uni-directional protection switching the switch state
      is independent of the switch state of the return LSP.
      In bi-directional protection switching both switches will
      switch simultaneously (both working LSP or protecting LSP).

Cheers, Huub.

> thanks,
> - dimitri.
>
> ps: purpose is not to "contrast" between protection schemes
>
> 	"Zafar Ali \(zali\)" <zali@cisco.com>
> Sent by: owner-ccamp@ops.ietf.org
>
> 19/12/2005 23:10
>
> 	       
>         To:        <ccamp@ops.ietf.org>
>         cc:        "Adrian Farrel" <adrian@olddog.co.uk>, Dimitri 
> PAPADIMITRIOU/BE/ALCATEL@ALCATEL
>         Subject:        A quick question on 
> http://www.ietf.org/internet-drafts/draft-ietf-ccamp-gmpls-recovery-e2e-signaling-03.txt
>
>
>
>
> Hi All,
>  
> It's a bit confusing how one would encode protection object for 
> dedicated 1:1 protection (without traffic duplication) and I thought it 
> deserves a confirmation.
>  
> I just wanted to confirm that to signal an LSP that is dedicated 1:1 
> protection, where
>
>     * Traffic is NOT duplicated at working and protecting LSP-es (i.e.,
>       this is not 1+1 protection),
>     * There is NO extra traffic on the protecting LSP (i.e., it's
>       dedicated protection), 
>
> we are expected to:
>
>     * Set O-bit in protection object to 1 in signaling protecting LSP,
>       to indicate that the protecting LSP is (only) carrying the normal
>       traffic after protection switching (i.e., It's NOT 1+1 setup). If
>       contrasting 1:1 with 1+1 is NOT the intended use of O-bit, what is
>       the intended use.
>     * LSP (Protection Type) Flags to 0x10 = 1+1 Bi-directional
>       Protection (for GMPLS optical LSPs). I.e., this is a dedicated
>       protection.
>
> If above is not the intended use of O-bit, I am not sure why O-bit is 
> defined (as protection LSP is expected to carry normal traffic after 
> switchover). In which is it expected to use 0x04 = 1:N Protection with 
> Extra-Traffic as LSP (Protection Type) Flags?
>  
> Thanks
>  
> Regards... Zafar
>  

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