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Hi Zafar,
I have a question to you. Why would you need a
dedicated 1:1 protection without allowing the protection LSP to be used for
carrying extra traffic? If the resources of the protection LSP are allocated
anyway and the LSP is totally dedicated to protect the working LSP you might as
well bridge the traffic on the protection LSP with an immediate benefit of much
better recovery time. The whole point of 1:1 protection is to allow using
resources of the protection LSP for something else - carrying extra traffic in
case of dedicated 1:1 or extra traffic and other protection LSPs in cases of
shared 1:1 protection.
The other thing to note is that extra traffic does
not have to be carried all the time or any time for that matter - 1:1 protected
service is provisioned in such a way that extra traffic could be carried over
idle protection LSP should such need arise in the future. Thus, Dimitri is
right: O-bit is set to zero for the protection LSP to signal the fact that
originally the protection LSP is going to be idle in a sense that it will not be
carrying the"normal" (read protected traffic) and is ready to carry extra
traffic.
Cheers and Happy Holidays,
Igor
----- Original Message -----
Sent: Tuesday, December 20, 2005 9:49
AM
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) .
Dimitri,
More
specifically, my question was mainly on what "LSP (Protection Type)
Flags" to use for, 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),
In
this case there is NO duplication of the traffic on the backup resource (it's
NOT 1+1). There is also NO extra traffic that protection resources carry.
Thanks
Regards... Zafar
thanks,
- dimitri.
ps: purpose is not to "contrast"
between protection schemes
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| "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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