xrt94l33 Exar Corporation, xrt94l33 Datasheet - Page 416

• Manufacturer Part Number: xrt94l33
• Description: Multi-channel, Multi-function Device Aggregates 3 Ds3/e3/sts-1 Into Oc3/stm-1
• Manufacturer: Exar Corporation

XRT94L33
Rev.1.2.0.
2.3.4.4
Once a given ATM cell has successfully passed through the “HEC Byte Verification” block, and has been
processed by the “Cell De-Scrambler” block, it will now be processed by the “Receive User Cell Filter” block.
Figure 101 presents the functional block diagram of the Receive ATM Cell Processor block with the “Receive
User Cell Filter” block highlighted.
Figure 101 Illustration of the “Receive ATM Cell Processor” Functional Block Diagram with the
“Receive User-Cell Filter” block highlighted
The Receive ATM Cell Processor block consists of four parallel User Cell Filters. These User Cell Filters are
connected in parallel, in the sense that the entire “receive” ATM cell traffic will be presented to the inputs of
each of the four “user-cell” filters, at the same time. Figure 102 attempts to clarify this phenomenon by
presenting an illustration as to how each of these user cell filters is connected to the ATM traffic.
Receive UTOPIA
Interface Block
Main Data Path
RxFIFO
RxFIFO
T
HE
R
ECEIVE
U
Calculation
Calculation
SER
Parity
Block
Parity
Block
C
ELL
3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
F
ILTER
De-Scrambler
Cell Payload
De-Scrambler
User Cell
Cell Payload
B
User Cell
Idle Cell
Filter
Block
LOCK
Idle Cell
Filter
Block
Filter
Block
Block
Filter
416
Cell Extraction
Cell Insertion
Cell Extraction
Cell Insertion
Processor
Processor
Verification
Processor
Processor
HEC Byte
Verification
Buffer/
Buffer/
HEC Byte
Buffer/
Buffer/
Block
Block
Receive GFC
Nibble-Field
Receive GFC
Output I/F
Nibble-Field
Output I/F
Microprocessor
Microprocessor
STS-3c/STS-12c
Processor Block
From Receive
Interface
Interface
Block
Block
POH
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