
PRELIMINARY
INVERSE MULTIPLEXING OVER ATM
PM7341 S/UNI-IMA-84
DATASHEET
PMC-2000223
ISSUE 4
INVERSE MULTIPLEXING OVER ATM
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
365
12.5 IMA Operations
IMA operations are controlled via commands issued to the RIPP (Receive IMA
protocol processor). In general, once started, the RIPP performs the hand
shaking of state transitions between the near-end and far-end of an IMA
connection.
12.5.1 Issuing a RIPP Command
The RIPP commands control the LSM and GSM state machines. The group is
identified by the group tag and the links involved are identified with a 32-bit
vector. The TX_LINK_VEC has one bit for each TX LID and bit 0 indicates TX
LID 0 and bit 31 indicates TX LID31.
For symmetrical operations, the RX LIDs are not known until the ICP cells from a
link are validated. The user controls the relationship between physical links and
the RX Link vector through the RX Physical Link Table in the RIPP Group
Configuration record. The RX physical Link Table should be configured
according to the TX LID values. For example, the physical link ID for the Link
with TX LID = 0 should be programmed as the RX physical link 0. When using
the RIPP commands, the physical link entered for RX physical link 0 will be
controlled by bit 0 of the RX_LINK_VEC and the physical link entered for RX
Physical link 31 in the table will be controlled by bit 31 of the RX_LINK_VEC.
For asymmetric operations, since there is not a TX link for each possible RX link
and the RX LIDs are not known until the ICP cells from a link are validated, the
user controls the relationship between physical links and the RX Link vector
through the RX Physical Link Table in the RIPP Group Configuration record.
There are no restrictions on how this table should be configured in asymmetrical
mode. The contents of the RX_PHY_TABLE do not depend on LID values.
When using the RIPP commands, the physical link entered for RX physical link 0
will be controlled by bit 0 of the RX_LINK_VEC and the physical link entered for
RX Physical link 31 in the table will be controlled by bit 31 of the RX_LINK_VEC.
The RIPP command procedure is as follows:
1) Wait until the “CMD_BUSY” bit in the RIPP Command Register is clear.
2) Once the CMD_BUSY bit is clear, write the necessary data for the
command registers 0x222 - -x22C (RIPP CMD_WR_DATA1 through RIPP
CMD WR_DATA3).