pxb4219 Infineon Technologies Corporation, pxb4219 Datasheet - Page 58

• Manufacturer Part Number: pxb4219
• Description: Iwe8 Interworking Element For 8 E1/t1 Lines
• Manufacturer: Infineon Technologies Corporation

4.3.1.6
The Segmentation Buffer is located in external RAM providing 256 bytes of memory for
each timeslot, totalling to 64 KB for 8 ports with 32 timeslots each. The buffer for each
timeslot consists of 4 blocks with 64 octets:
Buffer size = 8 Ports x 32 Channels x 4 Blocks x 64 Octets
In unstructured CES mode, one Segmentation Buffer per port provides 16 blocks.
In structured CES mode, a Segmentation Buffer per channel with a variable capacity
depending on the number of channels and the cell filling level is automatically configured
by the IWE8. The number of memory blocks depends on the bandwidth of the channel.
Thus for structured CES with N x 64-kbit/s there are N x 4 blocks per connection. Each
channel can occupy 1, 2 or 4 block-groups (4, 8 or 16 blocks). The first block-group
defines the reference slot number of the channel. The second, third and fourth block-
groups define the number of the corresponding interface slot of the channel.
The one-to-one relationship between timeslots and groups of memory blocks allows
dynamic re-configuration of a specific channel without disturbing other channels of the
same port.
Table 16
Cell Filling
AAL0
(octets)
4.3.1.7
The value, used for dummy fill of partially filled cells, is programmable in the Cell Fill
Register for Partially Filled Cells (“cfil”, see
information and are ignored at the receiver.
Table 17
part_fill of RAM1: AAL Receive Reference Slot (see
Transmit Reference Slot (see
Data Sheet
25-48
4-24
shows valid values for the cell filling level, which can be configured in the field
Segmentation Buffer
Padding Partially Filled Cells
Subblock Size
Cell Filling
AAL1, no
SDT
(octets)
Relationship between Cell Filling and
25-47
4-24
Cell Filling
AAL1, with
SDT
(octets)
25–47
4–24
Chapter
6.1.2.3). All other values are illegal.
58
Octets per
block
64
64
Chapter
PXB4219 / PXB4220 / PXB4221
Chapter
Segmentation Buffer
7.12). The fill octets carry no
Cells per
block
1
2
Operational Description
6.1.1.3) and RAM2: AAL
Octets per
cell
64
32
2002-05-06
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