CN8237EBGB Mindspeed Technologies, CN8237EBGB Datasheet - Page 198

• 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
6.4 GFC Flow Control Manager
6.4.2 The CN8237’s Implementation of GFC
6-42
mechanism that only works on the link from the end station to the first piece of
network equipment. The GFC protocols are defined and described in ITU
Recommendation I.361.
The CN8237 implements the GFC one-queue mode. The reassembly coprocessor
provides Auto Configure and Command Detection. The segmentation
coprocessor provides Halt Processing and Per-transmit Queue SET_A control. It
does not implement the optional Queue B.
Section
coprocessor to halt processing of all channels, both controlled and uncontrolled.
This halt condition continues until a cell is received without the HALT indication.
GFC-controlled cell can be sent only when the GFC credit counter is equal to 1.
Transmission of a GFC-controlled cell decrements the credit counter by 1. Each
of the eight transmit priority queues can be configured for GFC control by setting
the appropriate GFCn bit(s) in the Scheduling Priority (SCH_PRI) register. In this
way, the SAR can segment both GFC-controlled and GFC-uncontrolled traffic
simultaneously. GFC-controlled queues are active only when the GFC credit
counter is equal to 1.
into a transmit priority queue. In addition, the segmentation coprocessor
implements a credit borrow algorithm that provides better utilization of the line
when receive and transmit cell streams are not synchronized. Up to one credit can
be borrowed.
GFC_DATA fields in the buffer descriptor entries. For GFC-controlled channels,
GFC_DATA = 0101; and for non-GFC-controlled-channels, GFC_DATA = 0001.
GFC provides a link-level, short-term, XON/XOFF-type flow control
Once the link has been configured for GFC operation (as described in
A received SET_A indication increments the GFC credit counter by one. A
CBR traffic is not affected by the SET_A command because it is not mapped
The user must control the transmitted GFC field via the HEADER_MOD and
6.4.2.1), a received HALT indication causes the segmentation
Mindspeed Technologies
ATM OC-12 ServiceSAR Plus with xBR Traffic Management
™
28237-DSH-001-C
CN8237