Performance Measurement in OcNOS: Y.1731 OAM and Y.1564 Service Acceptance Testing

Carrier Ethernet services require two distinct types of performance measurement: continuous in-service monitoring to detect degradation over time, and one-time acceptance testing to verify the service meets its committed parameters before customer handoff. ITU-T Y.1731 covers the first; Y.1564 covers the second.

This is Part 2 of the IP Infusion performance measurement series. Part 1 covers TWAMP for IP/MPLS networks.

Y.1731: Ethernet OAM for In-Service Monitoring

Y.1731 defines Ethernet Operation, Administration, and Maintenance (OAM) frames that measure performance metrics at Layer 2 — within an Ethernet service domain (MEG) defined between two Maintenance End Points (MEPs). Unlike TWAMP which operates at IP level, Y.1731 measures at the Ethernet frame level, providing accurate performance data for carrier Ethernet services regardless of IP routing changes.

Key Y.1731 Measurement Functions

! OcNOS -- Y.1731 MEG and MEP configuration
!
! Step 1: Define Maintenance Entity Group (MEG)
ethernet cfm domain CARRIER-SERVICES level 4
  service SVC-001 evc SVC-001
    continuity-check interval 1s
    continuity-check loss-threshold 3
  !
!
! Step 2: Define Maintenance End Points (MEPs)
interface eth-0-1
  ethernet cfm mep domain CARRIER-SERVICES service SVC-001
    mep-id 1
    direction down                   ! Toward customer
    cos 5                            ! High-priority OAM frames
!
! Step 3: Enable delay measurement toward remote MEP
ethernet cfm delay-measurement domain CARRIER-SERVICES service SVC-001
  mep 1 target-mep 2
  interval 1000                      ! Measure every 1 second
  frames 10                          ! 10 frames per measurement burst
!
! View delay measurement results:
show ethernet cfm delay-measurement domain CARRIER-SERVICES
! Output: avg delay, min/max delay, delay variation (jitter)

! OcNOS -- Y.1731 Frame Loss Measurement
!
ethernet cfm loss-measurement domain CARRIER-SERVICES service SVC-001
  mep 1 target-mep 2
  interval 10000                     ! Measure every 10 seconds
  cos 5
!
show ethernet cfm loss-measurement domain CARRIER-SERVICES
! Output: near-end loss, far-end loss, loss ratio %

Y.1564: Service Acceptance Testing

Y.1564 defines a two-phase test procedure that validates a carrier Ethernet service meets its committed bandwidth, delay, and loss parameters before being handed over to the customer.

• Phase 1 (Service Configuration Test) — verifies Committed Information Rate (CIR), Committed Burst Size (CBS), Excess Information Rate (EIR), and traffic policing behavior step by step at 25%, 50%, 75%, and 100% of CIR, then at EIR, then above EIR
• Phase 2 (Service Performance Test) — runs traffic at 100% CIR for a configured duration (typically 15 minutes to 24 hours) and measures frame loss ratio, frame transfer delay, and delay variation against SLA thresholds

! OcNOS -- Y.1564 service acceptance test configuration
!
y1564 service-test SVC-001-ACCEPTANCE
  !
  ! Phase 1: CIR step test (25/50/75/100% of 100Mbps CIR)
  phase1
    cir 100000                       ! 100 Mbps CIR
    eir 50000                        ! 50 Mbps EIR
    cbs 12500                        ! Committed burst size (bytes)
    step-duration 60                  ! 60 seconds per step
  !
  ! Phase 2: Performance test at full CIR
  phase2
    duration 900                     ! 15-minute sustained test
    cir 100000
    !
    ! SLA thresholds (test fails if exceeded):
    max-frame-loss-ratio 0.001       ! 0.001% = 1 frame per 100,000
    max-frame-transfer-delay 10      ! 10ms maximum one-way delay
    max-frame-delay-variation 5      ! 5ms maximum jitter
  !
!
! Execute test (Phase 1 then Phase 2 automatically):
y1564 service-test SVC-001-ACCEPTANCE start
!
! Monitor progress:
show y1564 service-test SVC-001-ACCEPTANCE status
!
! View final report:
show y1564 service-test SVC-001-ACCEPTANCE results
! Pass/fail per phase, per metric, with measured values vs. thresholds

• Performance Measurement: TWAMP
• Flex-Algo with Measured Link Delay
• OcNOS-SP Product Page
• Contact IP Infusion

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