Bsm Overview; Bsm Overview; Figure 5-1. Bsm Diagram - ADTRAN Total Access 5000 Deployment Manual

Total Access 5000 Business Services Deployment Guide

BSM Overview

Figure 5‐1 displays an overview of the BSM deployment.
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.
5-2
MSAP
Access
Module
Customer
Router
IP
PPP
S-tag
PPP
DS1

Figure 5-1. BSM Diagram

Edge
Router
Switch
Module
S-tag
GigE
GigE
Total Access
5000
IP
IPoE
S-tag
65K510DEP08-1A