RELEASED
PM73123 AAL1GATOR-8
DATASHEET
PMC-2000097
ISSUE 2
8 LINK CES/DBCES AAL1 SAR
While in the OUT_OF_SYNC state, three possibilities can occur.
1. If a cell is received with a valid SN and in the correct sequence, then the
SYNC state is entered and the previously stored cell is accepted.
2. If a cell with an invalid SN is received, then the START state is re-entered and
the previously stored cell is dropped.
3. If the cell has a valid SN but is in the incorrect sequence, then the previously
stored cell is dropped, the new cell is stored and the RALP remains in the
OUT_OF_SYNC state.
While in the SYNC state, three possibilities can occur.
1. If a cell is received with a valid and correct SN, the RALP remains in the
SYNC state. The stored cell is accepted and the new cell is stored.
2. If an invalid SN is received, the RALP goes to the INVALID state. The stored
cell is accepted and the new cell is stored
3. If a valid but incorrect SN is received, the OUT_OF_SEQUENCE state is
entered. The stored cell is accepted and the new cell is stored as the next
cell and also in the position it would reside if cells had been lost . If there is
not physically enough space in the buffer to store the second copy of the cell
an overrun condition is declared.
While in the INVALID state, four possibilities can occur.
1. If the cell received has an invalid SN, the START state is re-entered and the
stored cell is dropped.
2. If the cell received has a valid SN and is in sequence with the last valid SN,
then a misinserted cell is detected and RALP returns to the SYNC state, the
stored cell with invalid SN is dropped and the new cell is stored.
3. If the cell received has a valid SN and is equal to SN + 2 with respect to the
last valid SN, then the RALP returns to the SYNC state and the stored cell is
accepted and the new cell is stored.
4. Otherwise, if the SN is valid but does not meet any of the previous criteria,
then the stored cell is dropped, the new cell is stored and the
OUT_OF_SYNC state is entered.
While in the OUT_OF_SEQUENCE state, five possibilities can occur.
1. If the cell received has an invalid SN, the START state is re-entered and the
stored cell is dropped.
PMC-SIERRA, INC. PROPRIETARY AND CONFIDENTIAL
112
PMC [ PMC-SIERRA, INC ]
