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

From: "Zafar Ali \(zali\)" <[email-masked]>
Date: Mon, 19 Dec 2005 17:10:21 -0500

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

---

From: [email-masked]
Date: Tue, 20 Dec 2005 14:05:12 +0100

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)

thanks,
- dimitri.

ps: purpose is not to "contrast" between protection schemes

"Zafar Ali \(zali\)" <[email-masked]>
Sent by: [email-masked]
19/12/2005 23:10
 
        To:     <[email-masked]>
        cc:     "Adrian Farrel" <[email-masked]>, 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

---

From: Huub van Helvoort <[email-masked]>
Date: Tue, 20 Dec 2005 14:46:36 +0100

Hi Dimitri,

> 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.

>     * Traffic is NOT duplicated at working and protecting LSP-es (i.e.,
>       this is not 1+1 protection),
>       contrasting 1:1 with 1+1 is NOT the intended use of O-bit, what is
>       the intended use.

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