RELEASED
PM73123 AAL1GATOR-8
DATASHEET
PMC-2000097
ISSUE 2
8 LINK CES/DBCES AAL1 SAR
• For structured connection with CAS, PCR <= 182 x n cells per second per
connection where 1 <= n <= 32 (assuming completely filled cells).
• Each AAL1 cell is either 46 or 47 bytes, depending upon whether or not the cell
contains a structure pointer.
9.2.1.3.3.2Peak Cell Rates (PCRs) for Unstructured Cell Formats
• PCR <= 4,107 cells per second for T1 (assuming 47 bytes for each AAL1 cell).
• PCR <= 5,447 cells per second for E1 (assuming 47 bytes for each AAL1 cell).
• PCR <= 118,980 cells per second for T3 (assuming 47 bytes for each AAL1 cell).
• PCR <= 91,405 cells per second for E3 (assuming 47 bytes for each AAL1 cell).
• If all eight lines are at the same rate, totaling 20 Mbps throughput for the device,
then the aggregate device PCR <= 53,191 cells per second for multiple-line
unstructured data format (assuming 47 bytes for each AAL1 cell). If all lines are
not at the same rate, the aggregate device PCR <= 46,542.
• PCR <= 1,000 cells per second per device for OAM cells. This rate of OAM cells
is calculated on the basis of up to four cells per second per VC. Transmitting and
receiving OAM cells at this rate consumes 20% of the microprocessor accesses.
9.2.1.3.3.3Peak Cell Rates and Partial Cells
Partial Cells can be used to minimize the amount of delay required to assemble
a cell. However, the amount of overhead required for the same amount of TDM
data increases when partial cells are used. This overhead increases as the
number of data bytes per cell decreases. The following table shows the
minimum partial cell sizes that can be supported for the different modes of
operation if all connections are active on the device. If a smaller partial cell size
is desired, either some time slots/links must not be used or only a subset of the
connections must use that partial cell size. In any case the total PCR of the
device should not exceed 100,000 cells per second with a 38.88 MHz SYSCLK
or 110,000 cells per second with a 45 MHz SYSCLK.
Table 5 Minimum Partial Cell Size Permitted If All Connections Are Active
MODE
SYS_CLK=38.88 MHz SYS_CLK = 45 MHz
16 14
T1 SDF-FR
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