Specifications

2-2 Cisco MGX 8220 Reference, Release 4.1
System Overview
In racks that contain more than two shelves, a booster cooling unit is used to provide additional
cooling. The cooling assembly is powered from the main MGX 8220 shelf. An external view of a
single MGX 8220 shelf configuration is shown in Figure2-1. The arrangement of assemblies in a
rack including cases for multiple MGX 8220 shelves is provided in chapter 7, “Installation and
Start-up”.
Figure2-1 MGX 8220 Shelf Configuration
An MGX 8220 shelf consists of various kinds of modules. Each module consists of a larger front
card function module which provides the functionality of the module and a smaller back card which
provides the connectors and interfaces for the external lines that the module supports.
The MGX 8220 Shelf Controller (ASC) is the module that provides the overall control of the shelf.
Each MGX 8220 shelf must have at least one ASC and may be configured with a second (redundant)
ASC.
The ASC back card also provides the RS-232 ports and Ethernet port for attaching a control terminal
or workstation.
The Broadband Network Module (BNM) provides the interface to the BPX network over either a
T3 or E3 line using the ATM STI, UNI, or NNI protocol and the BPX BNI or BXM cards, or a
SONET OC-3 or STS-3c line using ATM UNI/B-ICI protocol. Each MGX 8220 shelf must have at
least one BNM and may be configured with an identical second (redundant) BNM. The BNM also
provides:
• an external alarm interface
• a fan monitor interface
• a port for accepting an external T1 or E1 clock source