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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
The major function of the BNM-15 5 is to provide a 155 Mbps SONET ATM interface to a BXM-8- 155
port or a BXM-4-155 port in a Cisco BPX 8600 series node. The BNM-155 also provide s the following
miscellaneous functions:
•Shelf mastership
This function selects which core card to use as the master and which redundant bus to use.
•Cell bus mastership
BNM-155 polls the other cards on the bus and grants permission to transmit cells across the bus.
Polling is performed on a round-robin basis.
•Clock selection
BNM-155 manages the clock selection and synchronization for the entire Cisco MGX 8220 shelf.
The BNM-155 selects, regulates, and ou tp u ts th e s ele cte d cl o ck f or u se by each service module in
the shelf. The BNM-155 back card contains a T1/E1 port for inputting an external T1/E1 clock
source (both D-15 and BNC are availa bl e) . Th e she lf ca n als o o b tai n its clock source from the
SONET trunk itself or use an internal clock source.
•External Alarm Interface
BNM-155 provides the activation of fo ur a lar m r el ay s th at are wired to a DB-15 conne cto r on t he
back card faceplate, allowing the c ust om er to wire their own cable from th e c onnector to an
indicator panel. The four rela ys are Major Alarm Audible, M ajo r A lar m Visual, Minor Alarm
Audible, and Minor Alarm Visual. The pinouts for this connector are provided in AppendixB,
“Specifications.”
•Miscellaneous monitoring functions
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Fan performance in the cooling assembly
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Input voltage levels
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Shelf intake air temperature
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In-band management
The BNM-155 provides a separate path for management of the Cisco MGX 8220 shelf using an ATM
VCC from across the ATM network.
ATM Trunk Interface Back Card
The BNM-155 card accepts and t ransm its ATM 53-byte cells over a SONET line interface a t
155.52Mbps using ATM UNI or ATM B-ICI protocols.
In UNI mode, 20 virtual circuit connections per slot are supported.
In NNI mode, 340 virtual circuit connections per slot are supported.
SMF-155 Back Card
The SMF-155 back card provides a ph y sica l s i ngle -mode fiber optic SONET OC-3 int er fac e
conforming to ANSI T1.105 and GR-253-CORE standards. This interface uses SC connectors. When
used in a redundant configur at ion, re du nda nt cabl ing is pr ovi ded th rou gh Y-cables.
The back card also p r ovi de s
•One-DB-15 female connector for T1/E1 clock input
•One-BNC connector for E1 clo ck in pu t
•One-DB-15 female connector fo r al ar m i nt er fac e