cn8237 Mindspeed Technologies, cn8237 Datasheet - Page 119

• Manufacturer Part Number: cn8237
• Description: Atm Oc-12 Servicesar Plus With Xbr Traffic Management
• Manufacturer: Mindspeed Technologies

CN8237
ATM OC-12 ServiceSAR Plus with xBR Traffic Management
5.3.2 AAL0 Processing
Figure 5-9. AAL0 PTI PDU Termination
28237-DSH-001-C
. . .
AALO PDU
5.3.2.1 Termination
5.3.2.2 AAL0 Error
. . .
ATM Cells
Conditions
Methods
PTI[0]=0
(Hdr)
(Payload)
AAL0 is a transparent adaptation layer, allowing for pass-through of raw data
cells during CPCS-PDU processing. AAL0 channels are intended to be used for
AAL proprietary adaptation layers.
EOM and PTI termination.
for each VCC.
Status Queue entry for that channel. See
entry, with the LEN_ERROR and EPD status bits set. Refer to
details on how this process is handled.
underflow, status queue overflow, and per-channel buffer firewall), in the same
way as AAL5 CPCS-PDUs are processed.
The CN8237 provides two methods of terminating an AAL0 PDU: Cell Count
The TCOUNT field in the RSM VCC state table entry determines the method
• If TCOUNT = non-0, Cell Count EOM PDU termination is enabled. PDUs
• If TCOUNT = 0, then PTI termination is enabled. In this case, a received
Figure 5-9
The CN8237 reports all PDU termination events, with or without errors, in a
If the CN8237 receives a non-EOM cell in PTI termination mode, where
EPD is performed. The CN8237 reports this condition via a status queue
For each EOM cell where
The CN8237 processes error conditions for AAL0 (such as free buffer queue
the PDU is completed, with BA_ERROR status bit set.
will terminate when a fixed number of cells (TCOUNT) have been
received. CCOUNT must be initialized to a value of one in this mode.
cell with PTI[0] set to one indicates the end of the AAL0 message. The
total maximum allowable length of an AAL0 PDU in this mode is
(CCOUNT × 2) bytes.
Mindspeed Technologies
TOT_PDU_LEN + 48 > CCOUNT × 2,
TOT_PDU_LEN + 48 > CCOUNT × 2,
provides an illustration of this.
PTI[0]=0
(Hdr)
(Payload)
™
Section
. . .
. . .
5.6.
PTI[0]=1
5.0 Reassembly Coprocessor
(Hdr)
5.3 CPCS-PDU Processing
(EOM Cell)
Section
(Payload)
5.4.7, for
8237_047
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