CN8237EBGB Mindspeed Technologies, CN8237EBGB Datasheet - Page 48

• 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

2.0 Architecture Overview
2.4 Automated Reassembly Engine
2-14
reassembly process, including the following:
of complete or partial CPCS-PDUs based upon service discard attributes or error
conditions. The early packet discard function halts reassembly of the CPCS-PDU
marked for discard until the next Beginning of Message (BOM) cell and/or the
error condition has cleared. The SAR writes a status queue entry with the
appropriate status flags set, which indicate the reason for the discard. This
function can be enabled for the following conditions:
either Message Mode or Streaming Mode. In Message Mode, a status entry is
written only when the last buffer in a message completes reassembly. In
Streaming Mode, a status entry is written for each buffer as it completes
reassembly.
The CN8237 provides the user with generous per-channel control of the
• Assignment of priorities for reassembly buffer return processing.
• Cell filtering on inactive channels.
• Mechanisms to establish per-VCC firewalling by allocating buffer credits
• Per-VCC activation and control of a background hardware time-out
• Per-VCC monitoring of the length of the reassembled PDU, with status
The CN8237 implements an early packet discard feature to enable discarding
• Frame Relay discard based on the frame’s DE setting and the channel
• CLP packet discard based on the received cell’s CLP bit setting and
• LANE-LECID packet discard on ELAN channels, which implements echo
• Early packet discard on AAL5 channels when the reassembled PDU length
• Early packet discard on channels encountering a free buffer queue empty
• Early packet discard on PDUs when a DMA Incoming FIFO buffer Full
• Early packet discard on channels encountering a reassembly status queue
The system designer can set the reassembly status reporting for any channel to
on a per-channel basis. (This limits the possibility of one VCC consuming
all of the memory resources.)
function where the user selects one of eight programmable time-out
periods. (The background function then automatically detects partially
reassembled PDUs and reports this status to the host so that these buffers
can be recovered and re-allocated.)
reporting if the length exceeds a set maximum length for that channel.
exceeding a user-defined priority threshold.
exceeding channel priority threshold.
suppression on multicast data frames.
exceeds the user-defined maximum PDU length for that VCC.
(underflow) condition (meaning there are no available buffers in the free
buffer queue that channel is assigned to).
condition occurs.
full (overflow) condition.
Mindspeed Technologies
ATM OC-12 ServiceSAR Plus with xBR Traffic Management
™
28237-DSH-001-C
CN8237