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CHAPTER 4 ATM CELL PROCESSOR
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Preliminary User’s Manual S14767EJ1V0UM00
(2) Max No. of segments violation
This error occurs if the last cell of a packet has not been received when the number of cells received has reached
the user-specified "Max. no. of segments." When the next cell is received, the RID bit is set and a receive indication is
issued. The subsequent cells of the packet, including the last cell, are discarded.
(3) CRC-32 error
This error occurs if the CRC-32 value does not match the CRC-32 value contained in the receive trailer when all
the data in the packet has been transferred to SDRAM. If a check made on the trailer reveals that the received packet
has both CRC-32 and "length" errors, the CRC-32 error is reported as the error status in the receive indication.
(4) "length" error
This error is reported if the "length" field contained in the receive trailer and the calculated packet length satisfy
either of the following conditions:
("Number of received cells x 48 bytes" - ""length" value in the trailer") > 55 bytes
("Number of received cells x 48 bytes" - ""length" value in the trailer") < 8 bytes
(5) T1 time-out
This error occurs if the last cell of a packet has not been received even after the user-specified A_T1R time has
elapsed since the first cell was received. When this error occurs, the RID bit is set and the remaining cells of the
packet that caused this error, including the last cell, are discarded.
The table below lists the errors that can occur with any of the first cell, the immediate cells, and the last cell of a
packet.
Table 4-4. Reception Errors That Can Occur During Packet Reception
Error
When a cell is discarded
When a receive indication is
issued
Handling of other cells after
the error occurred
Free buffer underflow
The cell received when the
size of the free buffer is
insufficient is discarded.
Time at which transfer
becomes impossible during
segment transfer
The subsequent cells of the
packet, including the last
cell, are discarded.
MAX No. of Segments error
The cell received after MAX
No. of Segments was
reached is discarded.
Time at which the next cell
is received after MAX No. of
Segments was reached
The subsequent cells of the
packet, including the last
cell, are discarded.
T1 error
The cell received after the
T1 time has elapsed is
discarded.
Time at which T1 time has
elapsed.
The subsequent cells of the
packet, including the last
cell, are discarded.
Two or more errors may occur at the same time; however, only one is reported with a receive indication. The table
below lists the error reporting priorities.