Linear Protection for MPLS-TP
draft-weingarten-mpls-tp-linear-protection-01.txt
Stewart Bryant
<stbryant@cisco.com>
Yaacov Weingarten
<yaacov.weingarten@nsn.com>
Nurit Sprecher
<nurit.sprecher@nsn.com>
Annamaria Fulignoli
<annamaria.fulignoli @ericsson.com>
Huub van Helvoort
<hhelvoort@huawei.com>
John E. Drake (contributor) <john.e.drake2@boeing.com>
MPLS-TP - 74th IETF (SanFran)
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TP Requirements
#56: MPLS-TP MUST support 1+1 protection
Bidirectional P2P
Unidirectional P2P and P2MP
#57: MPLS-TP MUST support 1:n (1:1) protection
Bidirectional P2P
Unidirectional P2MP
MPLS-TP - 74th IETF (SanFran)
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Linear protection
Linear protection provides a fast and simple
protection switching mechanism.
It provides a clear indication of the protection
status.
Linear protection fits best in mesh networks.
MPLS-TP - 74th IETF (SanFran)
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Draft highlights
Terminology based on RFC 4427
Provides architecture of 1+1 and 1:1 protection schemes
Description of the process
Currently, cover 1+1 uni&bi-directional p2p, 1+1 unidirectional
p2mp, 1:1 bi-directional p2p, and 1:1 unidirectional p2mp
1:n for further study, possibly in separate draft
Proposes a protocol for Protection Switching Coordination
(PSC)
Transmitted over G-ACh
Presents a logical architecture for the PSC process
MPLS-TP - 74th IETF (SanFran)
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Unidirectional 1+1 Protection Switching
Protection Condition
Failure Condition
Normal
Protection Domain
Working Entity
Permanent
Bridge
Protection Entity
Selector
Working Entity
Permanent
Bridge
Protection Entity
Selector
MPLS-TP - 74th IETF (SanFran)
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Bidirectional 1:1 Protection Switching
Protection Condition
Failure Condition
Normal
Protection Domain
Working Entity
Fully allocated resources
Permanent
Bridge
Protection Entity
Selector
Working Entity
Permanent
Bridge
Protection Entity
Selector
MPLS-TP - 74th IETF (SanFran)
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Protection Switching Trigger Actions
Protection switching may be performed when:
A failure condition (‘failed’ or ‘degraded’) is detected (either by
OAM or by control plane) on the active entity and is not declared
on the recovery entity.
An external operator command is received (e.g. ‘Forced Switch’,
‘Manual Switch’).
A request to switch over is received from the far end - relevant in
case of 1:1 protection switching only!
Priorities between the various triggers will be defined in
future draft.
MPLS-TP - 74th IETF (SanFran)
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Protection Switching Coordination
Necessary for bidirectional protection and for all 1:1
protection
Allows coordination between the end-points of protection domain
Used to coordinate protection of unidirectional faults
Used to verify that both ends are operating under the
same configuration
Revertive vs Non-revertive
Presented as a single-phase protocol
MPLS-TP - 74th IETF (SanFran)
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Next Steps
Resolve open issues
How closely to adhere to Y.1731/G.8031 format for PSC
Should 1:n protection be covered in a separate
document.
• Need clear definition of 1:n as opposed to (1:1)^n
• 1:n protection requires more coordination – not a single phase
protocol
Request adoption as working group draft
Other comments?
MPLS-TP - 74th IETF (SanFran)
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