cn8237 Mindspeed Technologies, cn8237 Datasheet - Page 124

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

5.0 Reassembly Coprocessor
5.4 Buffer Management
5.4.3 Linked Data Buffers
Figure 5-12. Data Buffer Structures
5-16
NOTE(S):
No user fields in buffers - payload data only.
Buffer Descriptors
(Host Memory)
NEXT_PTR
BUFF_PTR
NEXT_PTR
BUFF_PTR
BUFF_PTR
NULL
After the free buffer queue has returned pointers to a buffer descriptor and a cell
buffer, the reassembly coprocessor writes payload data to the buffer.
buffers do not contain any control information. A pointer in a separate buffer
descriptor structure links the buffers.
descriptor, which has a pointer (BUFF_PTR) pointing to a buffer. The use of this
buffer locating mechanism offers a layer of indirection in buffer assignment that
maximizes system architecture flexibility.
the buffer descriptor, which is written by the reassembly coprocessor when the
current buffer is completed. The host writes the second word of the buffer
descriptor to point to the next associated data buffer. The link pointer of the last
buffer descriptor in a chain is written to NULL.
VCC table entry for that channel is a logic low.
NOTE:
The linked cell buffers contain the payload portions of the ATM cells. The
Thus, the pointer in the free buffer queue (BD_PNTR) points to a buffer
Figure 5-12
The data buffers are linked by a pointer (NEXT_PNTR) in the first word of
The link pointer (NEXT_PNTR) is not written if the LNK_EN bit in the RSM
For more information about big and little endian processing, refer to
Section
Mindspeed Technologies
8.4.
illustrates this structure.
ATM OC-12 ServiceSAR Plus with xBR Traffic Management
™
(Host Memory)
Buffers
28237-DSH-001-C
CN8237
8237_050