delaymeasurement provides fine controlto operators for triggering delay measurement
ona given service and can be used to monitor Service LevelAgreements (SLAs).
Ethernetframe delay measurementalso collects other useful information, such asworst
andbest case delays, averagedelay, and average delayvariation. Ethernet frame delay
measurementsupports hardware-based timestampingin the receive direction for delay
measurements.It also provides runtime display of delaystatistics when two-way delay
measurementis triggered. Ethernet frame delaymeasurement records the last 100
samplescollected per remote maintenanceend point (MEP) or per connectivity fault
management(CFM) session. You canretrieve the history at any time using simple
commands.You can clearall Ethernet frame delay measurement statistics and PDU
counters.Ethernet frame delay measurementis fully compliant with the ITU-T Y.1731
(OAMFunctions and Mechanisms for Ethernet-based Networks)specification.
Ethernetframe delay measurement uses the IEEE 802.1agCFM infrastructure.
Anoverview of the architecture established forEthernet OAM is shown in Figure 18 on
page120.Generally, Ethernet framedelay measurements are made in a peer fashionfrom
oneMEP or CFM session to another. However,these measurements are not made to
MaintenanceIntermediate Points (MIPs).
Figure18: Ethernet OAM Overview
Thereare two types of Ethernet frame delaymeasurements:
•One-way
•Two-way(round-trip)
Forone-way Ethernet framedelay measurement, either MEP can send a request to begin
aone-way delay measurementto its peer MEP. However,the statistics are collectedonly
atthe receiver MEP. Thisfeature requires the clocks at the transmittingand receiving
MEPsto be synchronized. If these clocks fallout of synchronization, only one-way delay
variationand averagedelay variation valuesare computed correctly(and therefore valid).
Usethe show commands at the receiver MEP to displayone-way delay statistics.
Copyright© 2010, Juniper Networks,Inc.120
Junos10.4 MX Series Ethernet ServicesRouters Solutions Guide