MPLSTP Ring Protection draftweingartenmplstpringprotection draftceccarellimplstpp2mpring

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MPLS-TP Ring Protectiondraft-weingarten-mpls-tp-r
ing-protectiondraft-ceccarelli-mpls-tp-p2mp-ring
Yaacov Weingarten (yaacov.weingarten_at_nsn.com)
Stewart Bryant (stbryant_at_cisco.com), Nurit
Sprecher (nurit.sprecher_at_nsn.com), Daniele
Ceccarelli (daniele.ceccarelli_at_ericsson.com) Diego
Caviglia (diego.caviglia_at_ericsson.com)
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MPLS-TP Criteria for dedicated ring protection

• MPLS-TP Requirements identifies five criteria for
  defining a special protection mechanism for a
  specific topology
• Minimize the number of OAM entities needed to
  trigger the protection
• Minimize the number of recovery objects needed
• Minimize number of labels required
• Minimize number of control and management plane
  transactions during a recovery operation
• In presence of control plane, minimize impact of
  signaling and routing information exchanged
• Note no requirement has been identified to be
  specific to a ring topology

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Status of the drafts

• Have agreed to merge the current drafts into a
  single applicability document
• Define the problem statement
• Need to address p2p and p2mp LSPs that cross a
  MPLS-TP ring
• Need to address both link failure and node
  failure in the ring
• Show how we can present solutions that are
  dependent upon existing mechanisms without the
  need to add any new mechanisms
• The proposed solutions that fulfill the
  requirements and achieve the behavior of the
  criteria defined in the TP requirements

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P2P solution - Steering

• Trigger switching
• Run OAM sessions on PST and alternate PST from
  each node to each other node (O(2n) sessions per
  node)
• Use AIS functionality to notify ingress MEP
• Ingress node transmits protected traffic on
  working or recovery PST
• Identical to 11 linear protection, turning the
  ring into a lower layer protected span

C
B
A
D
E
F
Working segment (PST)
Recovery segment (PST)
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P2MP Option 1 11 protection

• Replicate data on both the working and recovery
  PST
• Each node needs to forward packet and examine
  local copy of stack to identify packets to egress
• Each egress decides on basis of strength of
  signal which data to use
• No need for coordination between the egress and
  ingress

C
B
A
H
D
E
F
G
Working PST
Recovery PST
Cont Recovery PST
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P2MP Option 2 ROM FRR
A

• Optimize wrapping of p2mp by configuring
  alternate paths for each protected element
• N alternate paths configured for each LSP
• Support local switching that is wrapped until
  farthest egress
• Appropriate for specific applications (e.g. Video
  distribution in metro rings)

F
B
DSLAM3
C
E
D
DSLAM2
p2mp working LSP (cw)
p2mp protection LSP (ccw)
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Conclusions and Next Steps

• Develop applicability draft to propose
  solutions based on existing MPLS survivability
  technologies that
• Optimize
• The numbers of OAM Sessions,
• Number of alternate labels
• The bandwidth usage
• Work within the labeling mechanism of MPLS-TP
• There are still additional (4-5) ring protection
  drafts need to unify these with the proposal
  some of these are very similar
• Invite all authors to
• Spend the time to read our ID and check if they
  are fine with it
• join forces and produce single draft
• Final draft to WG draft