CN8237EBGB Mindspeed Technologies, CN8237EBGB Datasheet - Page 162

• Manufacturer Part Number: CN8237EBGB
• Description: ATM SAR 622Mbps 3.3V ABR/CBR/GFR/UBR/VBR 456-Pin BGA
• Manufacturer: Mindspeed Technologies

Specifications of CN8237EBGB

• Package: 456BGA
• Traffic Class: ABR|CBR|GFR|UBR|VBR
• Utopia Type: Level 1|Level 2
• Host Interface: PCI
• Maximum Data Rate: 622 Mbps
• Typical Operating Supply Voltage: 3.3 V
• Minimum Operating Supply Voltage: 3.135 V

6.0 Traffic Management
6.2 xBR Cell Scheduler Functional Description
6.2.1 Scheduling Priority
6.2.2 Dynamic Schedule Table
6-6
APPLICATION EXAMPLE: Application-Specific Templates
6.2.1.2 VCC Priority
6.2.1.1 16 Priority
6.2.2.1 Overview
Each template can have different flow control parameters. For instance, a system designer may
wish to configure a VCC traversing a network with all ER switches with a Rate Increase Factor
(RIF) and Rate Decrease Factor (RDF) = 1. However, a VCC traversing a network with switches
doing CI/NI (binary) marking will desire an RIF and RDF
be desired for these VCCs.
Levels + CBR
Assignment
ABR algorithm in a hardware state machine. However, to provide flexibility
against minor changes in the immature TM 4.1 specification, the state machine is
programmable through Mindspeed-supplied ABR templates. These templates,
resident in SAR SEG-shared memory, also provide a policy tuning mechanism for
interoperability and performance. Separate groups of VCCs can be assigned to
application-optimized templates according to their path through the network.
6.2 xBR Cell Scheduler Functional Description
The CN8237 supports 16 scheduling priorities (the PRI field in the SEG VCC
table entry), in addition to the optional CBR service category, with 15 being the
highest priority, down to 0 being the lowest priority. CBR channels are assigned a
priority which is in effect higher than the 16 scheduling priorities discussed here.
From one to 16 of these scheduling priorities can be assigned to VBR and ABR
service classes. The others are shared UBR priorities. The VBR/ABR priorities
must be contiguous within the 16 scheduling priorities, and thus accessible by an
offset pointer. The host sets the offset of the VBR/ABR priorities in the
VBR_OFFSET field of SEG_CTRL or SCH_CTRL.
The host assigns the priority of all VCCs, except CBR VCCs, by setting the PRI
field in the Segmentation VCC table entry. This priority should be set at
connection setup and should not be changed dynamically.
The xBR Cell Scheduler schedules traffic according to the Dynamic Schedule
table. The table contains a programmable number of slots, determined by
SCH_SIZE(TBL_SIZE). The duration of a single slot is a programmable number
of clocks cycles, set as the number of clock cycles per schedule slot, in
SCH_SIZE(SLOT_PER). The Cell Scheduler sequences through this table in a
circular fashion to schedule CBR, VBR, and ABR traffic. UBR traffic is handled
as described in
of each slot, the system designer chooses a range of available rates. This range of
available rates is dictated by the rate at which a single slot is scheduled, the size of
the table, and how many slots in the Dynamic Schedule table each channel is
assigned.
For optimal performance, the ABR Flow Control Manager implements the
Mindspeed Technologies
Section
6.2.5. By configuring the number of slots and the duration
ATM OC-12 ServiceSAR Plus with xBR Traffic Management
1. Thus, separate templates would
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28237-DSH-001-C
CN8237