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Cisco MGX 8220 Installation and Configuration
Release 5.0, Part Number 78-6430-03 Rev. D0, November 2003
Chapter
Core Module Overview
Core Module Overview
Cisco MGX 8220 modules include a larger front card to provide the functionalit y of the module, and a
smaller back card to provide the connectors and interfaces for exte rnal l in es . T he A S C an d th e B NM
are referred to as the core modules. Both m od u les m u st b e in s ta lle d in th e s h elf . If an op ti on al S RM is
also installed, it is considered a core module.
If redundancy is required, a second set of ASC and BNM modules must be configured. Failure of an
ASC or BNM causes s w itc hove r to the redundant A S C, B NM, and SRM cards. Fa ilu re of the active
SRM card only causes swi tch over i f th e S R M is als o i nc lu de d in the redundant set.
This section describes the following core module equipment:
•Cisco MGX 8220 ASC Shelf Controller, page 2-12
The ASC provides overall control of the shelf. Each Cisco MGX 8220 shelf m ust have at least one
ASC. The ASC back card also provides RS-232 and Ethernet ports to attach a control terminal or
workstation.
•Broadband Network Modules, page 2-14
The BNM provides the interface t o th e C isc o B P X n et work . Th e co n ne cti on to the Cisco BPX
network is made in one of the following two interface combinations:
–
T3 or E3 line using the ATM STI, UNI, or NNI protocol and the Cis co BPX B NI o r B XM ca rds.
–
SONET OC-3 or STS-3c line using ATM UNI/B-ICI protocol.
•Service Resource Modules, page 2-22
The optional SRM communica tes with all service modules over a bit error rate test (BERT) bus and
provides the capability for testing T1 and E1 and subrate service module lines. T he SRM can issue
various loopup and l oo p dow n commands toward the cu s t omer premises equipm ent (CPE), and
generate test bit patterns for any u ser sp eci fied nx64-kbps port. The SRM can also provide 1:N
redundancy for FRSM, AUSM, and CES M cards . Th e SRM-3T 3 pro v ides th e ad diti on al ca pabi li ty
of supporting multiple T1 channel s ov e r T3 li nes on the SRM a nd dis t rib ut ing thos e cha nn els to T1
service modules in the shelf.
The core modules work wi th t he s er vi ce m o du le s to provide the following f u nc tio n s:
•Accept customer traffic received over t he service interface lines, adapt them to ATM, and multiplex
them onto the BNM trunk for transmission to the Cisco BPX network.
•Accept ATM cells received over the BNM trunk, map them in to the specified service protocols, and
transmit them over the appropriate service interface.
Note Chapter 4, “MGX 8220 Service Modules”, contains information on the functionality of the v arious
service modules.
A simplified block diagram of the Cisco MGX 8220 hardware is shown in Figure2-10. As shown by
the dashed lines, the ASC, SR M , a nd ce ll bus are all 1:1 redundant. This me a ns t h at o n e A S C , B N M ,
and SRM slot set is attach ed to one cell bus, and the rema ining ASC, BNM, and SRM s lot set is tied to
the other cell bus.