
Nortel Networks 5399 Access Switch Hardware Installation Guide
Chapter1 Introduction
1-4
Modems TheModel 5399 Remote Access Concentrator Module can be configured
with up to62 internal DSP-based digital modems. The modems are
dynamically downloadedwith imagesto configure them to the
appropriate protocol.The modems are located on plug-in modem cards
installed on the module.
System 5000 Common Management BusThe management section of the back plane is the common management
bus(CM B), a high-speed,m ultimaster,shared-memory communication
channelthat connects all modules installed in the hub to one another and
tothe supervisory module. The modules installed in thehub use the CMB
to acquire and distribute configurationand status information.
The supervisory module is an intelligentinterface between the Model
5000 chassis and user-installedm odules.The supervisorymodule
provides the followingservices to other modules across the C MB:
• Maintains chassiscomponent information and
environmentalstatus
• Stores the primarymodule configurations
• Restoresthe module configuration after the module power is
cycled or the module is reset
The supervisory module also supports configurationte rminalsupport
through the servicepor ton thefront panel of the chassis.
System 5000 Backplane Ethernet Segment BanksThe chassis backplane Ethernet bus consists of 12 Ethernet segments,
divided intotwo banks of six segments each: segments 1 through 6 and
segments 7 through 12. Each Model 5399 Remote Access Concentrator
module installed in thec hassiscan be configured to access one bank of
sixsegments, either segments 1 through 6 or segments 7 through12. For
morein formation, see “Setting the Backplane EthernetSegment”onpage
2-3.