CN8236EBGB Mindspeed Technologies, CN8236EBGB Datasheet - Page 182

• Manufacturer Part Number: CN8236EBGB
• Description: ATM SAR 155Mbps 3.3V ABR/CBR/GFR/UBR/VBR 388-Pin BGA
• Manufacturer: Mindspeed Technologies

Specifications of CN8236EBGB

• Package: 388BGA
• Traffic Class: ABR|CBR|GFR|UBR|VBR
• Utopia Type: Level 1|Level 2
• Host Interface: PCI
• Maximum Data Rate: 155 Mbps
• Typical Operating Supply Voltage: 3.3 V
• Minimum Operating Supply Voltage: 3 V

6.0 Traffic Management
6.2 xBR Cell Scheduler Functional Description
6.2.3 CBR Traffic
6-14
APPLICATION EXAMPLE: Determining Maximum Rate
To achieve the maximum rate, the user would assign one VCC to every cell slot in the Schedule Table.
This would prevent any other VCC from being scheduled since this channel uses all of the available
slots.
6.2.3.1 CBR Rate
frequency(SYSCLK) = 33 MHz
SLOT_PER
Selection
R
max
= 354.8 K cells/second
The CBR service category guarantees end-to-end bandwidth through the network.
Certain data sources, such as voice circuits and constrained Cell Delay Variation
(CDV), require this guarantee. CDV is a measure of the burstiness of traffic. The
ATM network supplies a minimum CDV for CBR channels by reserving cell
transmission opportunities for the connections.
table to a CBR VCC. This connection always sends a single cell during its
assigned slots. The system clock serves as a time reference for CBR cell
generation. The systems designer programs the duration of schedule slots in clock
cycles in the SLOT_PER (slot period) field of the SCH_SIZE register.
Maximum Rate
For each CBR assigned cell slot, the CN8236 generates one cell on the specified
VCC. The maximum or base rate of CBR channels is determined by the duration
of a cell slot according to the equation below, where R
cells per second.
transmit a full cell, and its minimum bound should be no less than 70.
= 93 clocks/slot
The CN8236 generates CBR traffic by assigning specific slots in the Schedule
SLOT_PER must be nominally set to the number of clock cycles needed to
Mindspeed Technologies
SLOT_PER
=
ATM ServiceSAR Plus with xBR Traffic Management
clock frequency (SYSCLK or SCHREF)
------------------------------------------------------------------------------------------------ -
™
R
max
max
is the maximum rate in
28236-DSH-001-B
CN8236