BCM3212
®
DOCSIS
TM
1.1 ADVANCED CMTS MAC
•
Performs DOCSIS
TM
1.1 MAC layer functions, including:
Fragment reassembly
Deconcatenation
Payload header suppression and expansion
56-bit DES encryption and decryption
Generation and checking of HCS and CRC
MPEG encapsulation of downstream traffic
Timestamp and SYNC message generation

Supports one downstream and up to six upstream channels
simultaneously
Many other downstream-to-upstream ratios can be achieved by
connecting multiple BCM3212 devices via the seamless MAP
master/slave interface

Processes up to 400,000 packets per second in the aggregate
over all upstream and downstream channels

Direct interface to:
BCM3034 QAMLink® advanced universal QAM modulator
(providing downstream data rates up to 100 Mbps)
BCM3138 QAMLink® dual-channel advanced PHY burst
receiver (providing upstream data rates up to 30 Mbps per
upstream channel)

Packet port provides a high-throughput data interface to other
network equipment via the standard IEEE 802.3z GMII
Ethernet interface

PCI interface to external host CPU supports either 32-bit or 64-
bit operation at either 33 MHz or 66 MHz

PROPANE
TM
packet acceleration and SMART
SPECTRUM
TM
technologies included for increased upstream
performance
Hardware support for MAC-layer per-packet functions
including fragmentation, concatenation, and payload header
suppression offloads system CPU, giving higher overall system
performance.
Extraction of bandwidth requests and DOCSIS MAC
management messages allows software to access these
messages without examining data packets.
Class-based queuing allows traffic prioritization:
High, medium, and low priority downstream queues.
High priority, low priority, request, and MAC management
upstream queues
Support for carrier class redundancy via timestamp
synchronization across multiple BCM3212 devices.
Supports high packet rates for maximum utilization of
available cable plant bandwidth.
Out-of-band (OOB) generator for messaging to BCM3352-
based cable modems.
Can be remoted from external routing/classification engine for
distributed CMTS (mini fiber node) applications.
SPI master port controls register interface to BCM3034 and
BCM3138 devices.
Packaged in an 841-pin, thermally enhanced plastic ball grid
array.
Operates over industrial temperature range (–40 to +85
degrees C) PCI bus.
FEATURES SUMMARY OF BENEFITS
Upstream
Analog Inputs
BCM3138
Dual Adv. TDMA
Receiver
BCM3138
BCM3138
Upstream
SDRAM
(keys and
reassembly.)
Upstream
SDRAM
(PHS,
output
queues)
Routing/
Classification
Engine
Ethernet
System
CPU
Memory
PCI Bus
BCM3212
Advanced CMTS MAC
Downstream
SDRAM
(PHS,
output
queues)
BCM3034
Downstream
Modulator
Downstream
Analog Inputs
WAN
Typical Application Block Diagram