RELEASED
PM73123 AAL1GATOR-8
DATASHEET
PMC-2000097
ISSUE 2
8 LINK CES/DBCES AAL1 SAR
E1: Frame differential (in eighths of a multiframe) = (frame differential
+ FRAME_REMAINDER) / 2
T1: Frame differential (in eighths of a multiframe) = (frame differential
+ FRAME_REMAINDER) / 3
Frame differential = (9 + 1) / 3 = 10, or three-eighths of a multiframe,
remainder 1.
The CSD writes the remainder of this division into the FRAME_REMAINDER
location for use in the next calculation on this queue.
9) The CSD calculates the signaling credit adjustment by multiplying the
frame differential expressed in eighths of a multiframe by the number of
signaling bytes in a structure.
Number of signaling bytes in the structure = 4 channels x 0.5 bytes per
channel = 2 bytes per multiframe
Signaling adjustment = three eighths x 2 = 0.75 bytes
10) Then the CSD adds the signaling credit adjustment to the total and writes
the result to memory, in preparation for the next service on this queue.
QUEUE_CREDITS = 48.5 + 0.75 = 49.25 bytes
Unstructured lines use a different procedure. In the case of unstructured lines, a
cell will be sent every time 47 bytes are received. This assumes that no partial
cells are used for UDF mode.
For DBCES the algorithm is similar. The main change is that any time a channel
is activated or deactivated, the scheduling of the next bitmask cell has to
dynamically update to account for the change in the number of active channels.
If no channels are active a cell with an Inactive structure will be sent every 144
ms in T1 mode and 192 ms in E1 mode. DBCES is only supported for full cells.
9.2.1.2.1 Transmit CDV
The ideal minimum transmit CDV for all queue configurations is as follows. In
each case, the frame rate is assumed to be 125us.
• UDF-ML/LOW_CDV bit set: 0 us.
• SDF-FR/Single-DS0-with-no-pointer: 0 us.
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