VPLS OAM (draft-mohan-l2vpn-vpls-oam)

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VPLS OAM (draft-mohan-l2vpn-vpls-oam)

• L2VPN WG, IETF-72 (Dublin)
• Jul 28, 2008
• Dinesh Mohan (Nortel)
• Ali Sajassi (Cisco)
• Deborah Brungard, Henry Fowler (ATT)
• Philippe Niger (France Telecom)
• Simon Delord (Uecomm)

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Overview

• draft-mohan-l2vpn-vpls-oam-00.txt presented at
  IETF-71 (Philadelphia)
• General agreement that draft-mohan-l2vpn-vpls-oam
  covers VPLS monitoring using Ethernet OAM and
  VCCV/BFD/LSP Ping as described earlier
• Agreement reached during WG discussions to
  include VPLS PE model that had been implied in
  L2VPN Framework but need to be expanded for VPLS
  OAM
• WG agreement/support during WG meeting to
  progress it to WG status

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Updates from -00 to -01

• Updated the status of the draft to informational,
  as per the WG agreement
• VPLS/H-VPLS PE models included in -01 (Figure
  1.1, 1.2, 5 and 6), as per the WG agreement
• Updated Abbreviations, as per the feedback
• Updated References

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Next Steps

• draft-mohan-l2vpn-vpls-oam-01 needs to be
  submitted as WG draft, as was agreed in
  Philadelphia
• Continue work on the VPLS OAM, addressing
  feedback/comments

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Backup
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VPLS PE Model
Emulated LAN 1 Interface
Bridge Module
VPLS 1 Forwarder
PWs Full Mesh
VPLS 2 Forwarder
PWs Full Mesh
VPLS n Forwarder
PWs Full Mesh

• Agreement reached that above represents the
  correct VPLS PE Mode
• Implied in the draft, and presented in IETF-70
• Will be explicitly added to the draft in next
  revision

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H-VPLS PE Model
Emulated LAN 1 Interface
Bridge Module
PW Forwarder
VPLS UNI
Emulated LAN 1 Interface
Bridge Module
VPLS 1 Forwarder
Spoke PW
Core PWs full mesh
VPLS UNI
Spoke PE
Core PE

• Agreement reached that above represents the
  correct VPLS PE Mode
• Implied in the draft, and presented in IETF-70
• Will be explicitly added to the draft in next
  revision

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Solution Overview

• Solution offers significant functional coverage
• Proactive monitoring (fault detection)
• Diagnostics (fault verification, fault isolation)
• Performance monitoring (frame loss ratio, frame
  delay/variation
• Solution is applicable to monitoring
• VPLS as Bridged Service (Customer service)
• VPLS as Emulated (V)LAN (VPLS VSIs connectivity)
• MPLS domain (PW/LSP Monitoring)
• Solution proposes using
• IEEE 802.1ag/ITU-T Y.1731 for Service/LAN
  Emulation
• VCCV (Ping/BFD) for MPLS domain

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Solution Applicability (1)
U-PE
N-PE
N-PE
U-PE
VPLS UNI
VPLS UNI
Bridge Module
Bridge Module
Bridge Module
Bridge Module

• H-VPLS shown here (same solution applies since
  VPLS is simplified version)
• Ethernet Service layer can be monitored via
  Ethernet OAM and fault is localized to U-PE to
  N-PE, or N-PE to N-PE, or N-PE to U-PE segments
• PW OAM (VCCV using BFD/LSP Ping) is used to then
  determine if Spoke PW or Core PW is at fault
• Finally, if PWs are up, PW forwarder or VPLS
  forwarder is the suspect location

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Solution Applicability (2)
U-PE
N-PE
N-PE
U-PE
VPLS UNI
VPLS UNI
Bridge Module
Bridge Module
Bridge Module
Bridge Module

• H-VPLS shown here (same solution applies since
  VPLS is simplified version)
• Emulated LAN can be monitored via Ethernet OAM
  (different MD Level than Ethernet Service) and
  fault can be localized to N-PE to N-PE
  connectivity
• Scales much better than running BFD across each
  PW in full mesh per VSI
• PW OAM (VCCV using BFD/LSP Ping) used to
  determine if Core PW at fault
• Finally, if PW is up, VPLS forwarder is the
  suspect location

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VPLS OAM Requirements Conformance
OAM Requirement draft-mohan Comments
Discovery Multicast LBM (on-demand) CCMs may be used (proactive) Validate OAM monitoring end-points for a VPLS service Instance
Fault Detection CCMs are used different periodicity is allowed (e.g. 10ms to 10min) Fault detection is a proactive operation Used to detect failure in continuity between VPLS Service Endpoints and also between VPLS Forwarders
Fault Verification Unicast LBMs VPLS forwarder treat these frames as data frames Connectivity between two monitoring points can be established
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VPLS OAM Requirements Conformance
OAM Requirement draft-mohan Comments
MTU Verification and data pattern diagnostics Unicast LBMs with Data or Test TLV To exercise different MTU sizes or exercise different bit patterns in payload
Fault Localization LTM/LTR for detecting issues at Ethernet Layer, once a problem has been isolated to specific PW in MPLS domain, MPLS domain mechanism to be used Localize the fault as close to its occurrence as possible
Frame Loss Ratio Using statistical sampling described in Y.1731 Determine frame loss performance metric, an integral component of SLAs
Frame Delay/Variation Y.1731 mechanisms can be applied Determine frame delay and frame delay variation performance metric, integral components of SLAs
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draft-stokes-vkomplella-l2vpn-vpls-oam-01

• View of the perceived problem space based on
  offline discussions was presented during IETF-71
  meeting, and the discussions are expected to
  continue
• draft is proposing to address problem when
  implementation/protocol bug may lead to scenario
  where CPU access of FIB (Forwarding Information
  Base) may present a different view than data
  plane access of same FIB AND such a situation is
  limited to a very small sub-set of MAC lookup
  entries (e.g. specific customer MAC addresses)
• This problem certainly does not occur when
  PBB/PBB-TE is front-ending a VPLS/H-VPLS since
  monitoring entities and data plane uses the same
  MAC address space