Name: ADTRAN Total Access 5000
Brand: ADTRAN
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Total Access 5000 Business Services Deployment Guide

D-2 65K510DEP08-1A

TWAMP Overview

TWAMPisamechanismbywhichIPperformancemetricsandpacketlosscanbeobtained

acrosstheMetroEthernet.Thesetypesofmetricsverifythatacertainservicelevelisbeing met

acrossthenetworkthatwasagreeduponbetweenthecustomerandtheserviceprovider.

TWAMPallowsaunitin

theMetroEthernettosetupand sendIP packetstoadestinationunit

intheMetroEthernet.Thedestinationunitreceivesthepacketandtransmitsitrightbackto

thesendingunit.Thepacketcontainstimestampsinsertedbythesendinganddestination

unitsthatindicatesendingtime,timereceivedand

re‐transmittedat thedestination unit,and

thetimereceivedbackatthesendingunit.Withthisinformation,thesendingunitcan

calculatethefollowingstatistics:packetloss,two‐wayla tency,anddirectional/one‐wayjitter.

NOTE

TheNCTEonlysupportsreflectormode.

TWAMP Provisioning

InTWAMPterminology,thesourcenodeorsenderiscalledtheʺses si o n ‐senderʺandthe

reflectorissimplycalledtheʺses si o n ‐reflectorʺ.Inaddition,thesourcenodeusuallyhasthe

responsibilityofinitiallyrequestingaTWAMPsessiontocommence.InTWAMPterminology

thisiscalledtheʺControl‐Clientʺ‐sometimesjust

abbreviatedtoclient.Thereflectornode

alsohasanotherroleofbeingtheTWAMPʺserverʺ.Theʺserverʺisresponsibleforaccepting

theTWAMPrequestsfromthesourcenode.

TheTWAMPprotocolcanbedividedupintothe4logicalstates.Eachphasecommences

sequentiallyintimeinanormalTWAMP

probeexchange:

•Theconnectionsetupphase(runoverTCP)

•Thetestsessionsetupphase(runoverTCP)

•Theactivetestsessionphase(runoverUDP)

•Thetestsessionendandpmretrievalphase(runoverTCP)

NOTE

Theactivetestse ssion phaserunsoverUDP,whereastheother3phasesall

runoverasingleTCPconnection.

TWAMP Connection Setup

Thehostthatinitiatesthetcpconnectiontakestheroleofcontrol‐clientandsessionsender.

ThehostthatacknowledgestheTCPconnectionisthesession‐reflector.

TWAMP Test Session Setup

Thesession‐reflectordoesNOTprocessincomingtestpacketsforPMmetricsanddoesnot

careaboutthesendschedule.Consequently,thenumberofscheduledslotsandnumberof

packetsintherequest‐sessioncommandmustbesetto0.

SenderUDPportistheUDPportusedforsendertransmission.

ReceiverUDPportistheUDP

portusedforreflectortransmission.

ADTRAN Total Access 5000 Specifications

Interfaces

craft interface	DB-9 RS-232 Electrical Interface (Async)
admin interface	DB-9 RS-232 DTE Electrical Interface (Async with Modem Control Signals)
network management port	DB-9 RS-232 DTE Electrical Interface (Async)
ethernet interface	10Bt
external alarm inputs	16

Operating Environment