ADTRAN Total Access 5000 - BSM Overview; Figure 5-1. BSM Diagram

Total Access 5000 Business Services Deployment Guide
5-2 65K510DEP08-1A
BSM Overview
Figure5‐1displaysanoverviewoftheBSMdeployment.
Figure 5-1. BSM Diagram
Intheupstreamdirection,customerIPdataarrivesattheaccessmoduleencapsulatedwithin
aPoint‐to‐PointProtocol(PPP)group.T1stransportthePPPtraffic,whiletheNetwork
ControlProtocol(NCP)withintheLinkControlProtocol(LCP)initiatedsessionmanages
the
operationofthePPP.TheInterworkingFunctionde‐encapsulatesthecustomerIPfromthe
PPPandre‐encapsulatesthecustomerIPinEthernet.DSCPvaluesfromthePPPIPtraffic map
directlytop‐bitstosetthepriorityoftheEthernetframes,whichthentraveltotheswitch
module’scross‐connectasadesignatedbridge.Theswitchmodulecross‐connectsthebridge
totheappropriateS‐taggedVLANontheGigEnetworkportsdesignatedfortheupstream
edgerouter.
Inthedownstreamdirection,theswitchmoduleswitchesontheouterVLANVIDtothe
appropriatebridgeofanaccess
module’scustomerdataflow.Attheaccessmodule,theInter‐
workingFunctionde‐encapsulatesthecustomerIPtrafficfromeachEthernetflowandre‐
encapsulatesitinPPP,deliveringittooneoffouregressqueuesbasedontheEthernetframe
p‐bitvalues.
MSAP
Customer
Router
Total Access
5000
IP
PPP
S-tag S-tag
PPP
Edge
Router
Access
Module
Switch
Module
DS1
GigE
GigE
IP
IPoE
S-tag