Specifications

Common Equipment Description 2-5
MGX 8220 Shelf Hardware
The Cisco ATM LMI extension (which must be specifically enabled) uses a Node Update Status
Message which is sent (BPX 8620 to MGX 8220 shelf or MGX 8220 shelf to BPX 8620) whenever
a change in Node Name, Node IP Address, Major Alarm Status, or Minor Alarm Status occurs. The
message may optionally contain Qbin Status thereby allowing MGX 8220 to configure the BNI port
egress queues.
Auto Card Restore
Auto Card Restore is a feature which allows a service module card to be removed and be hot plug
replaced with another service module card keeping the same configuration. With this feature, the
ASC maintains a copy of the configuration for each active service module.
MGX 8220 Shelf Hardware
The MGX 8220 shelf is a 19 inch rack mountable unit conforming to the EIA RS-310-C standard
and measuring:
• 8.75 inches (5u) high
• 17.45 inches wide
• 21.25 inches deep (without cards) or 23 inches deep with back cards and fan connector.
The shelf contains a card cage with 16 slots. The slots are numbered 1 to 16 from the left looking at
the front of the shelf.
A backplane runs across the card cage spanning all 16 slots. The backplane is positioned
approximately 14 inches from the front of the cage allowing a function module card to be inserted
in the slot from the front and a smaller line module card to be inserted in the slot from the rear.
Slots 1 and 2 are reserved for BNM cards (single or a redundant pair) and slots 3 and 4 are reserved
for ASC cards (single or a redundant pair). Slots 15 and 16 are reserved for the SRM (single or
redundant pair). Slots 1, 3, and 15 work together as an active or standby set, the same is true for slots
2, 4 and 16. Slots 5 through 14 (10 slots) are available for Service Modules (or IMATMs). For
1:N redundancy of T1/E1 service modules standby cards must use slots 12, 13, and 14.
The shelf may house redundant power entry modules which are small cards installed horizontally in
the bottom rear of the shelf. The MGX 8220 shelf is powered by –48V DC power sources (single or
redundant pair). Each power entry module is equipped with a circuit breaker. The shelf also provides
a power receptacle for a cable to the cooling assembly which is mounted in the rack below the
MGX 8220 shelf (or shelves).
The backplane provides redundant system buses for communication between slots, power
distribution to all slots and communication between front and back cards. Figure2-3 and Figure2-4
show the front and rear views of the MGX 8220 shelf.