S/UNI-IMA-4 Telecom Standard Product Data Sheet
Released
WORD
BIT
DATA FIELD
DESCRIPTION
3:0
RX_M_RANGE
4-bit vector indicating the M values deemed
acceptable. Used during group parameter
negotiation.
Bit 3: M = 256 (‘0’: unacceptable, ‘1’:
acceptable)
Bit 2: M = 128 (‘0’: unacceptable, ‘1’:
acceptable)
Bit 1: M = 64 (‘0’: unacceptable, ‘1’:
acceptable)
Bit 0: M = 32 (‘0’: unacceptable, ‘1’:
acceptable)
3
31:26
25:16
RESERVED
RX_DELAY_TOL
Receive differential Delay tolerance. This field
is the maximum allowed amount of delay to be
accumulated for a link within the group. This
threshold will be used in determining if links
are acceptable for adding to a group. This
must be set to a value greater than
RX_DELAY_GUARDBAND+min_lower_guard
band+min_upper_guardband.
15:11
10
RESERVED
RX_ADD_DELAY_EN
Receive IMA group delay-adding enable.
When enabled, the RIPP will roll back the
RDAT read pointers, which effectively adds
more delay to the group, in order to
accommodate the new link if it is necessary.
‘0’: disabled.
‘1’: enabled.
9:0
RX_DELAY_GUARD_BAN Receive IMA group link differential delay
D
guard-band value. This is the suggested
distance between RDAT cell write pointer on
the slowest link and the RDAT cell read pointer
(expressed in the unit of cells), which is set by
RIPP when it activates the RX data path
during group start-up. This value is not used
after group start-up. A guardband placed at
group startup will help allow admittance of
slower links later. This guardband is in
addition to the min_lower_guardband defined
in the Delay Configuration Register, which
accounts for pointer jitter.
Note that this is only a recommended
behavior; if necessary, RIPP may choose to
not to maintain this guard band in order to
accept a slow link.
If RX_ADD_DELAY_EN is disabled, then the
RX_DELAY_GUARDBAND should be
configured to a value of 3 or greater in order to
prevent rejection of link additions solely due to
differential delay measurement jitter
(associated with ICP cells and stuff events).
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2020889, Issue 2
157
PMC [ PMC-SIERRA, INC ]
