S/UNI-IMA-4 Telecom Standard Product Data Sheet
Released
When links are deleted from a group, the DCB buffer depths of the remaining links are not
affected. As shown in Figure 20, links 2 and 3 have been deleted from the group and the depth
of the delay compensation buffers remain unchanged.
Figure 20 Snapshot of DCB Buffers after deletion of links from group
DCB
DCB
DCB
DCB
Link 0
Link 1
Link 2
Link3
Write
Pointer 0
15
14
13
11
9
Removed
from
Removed
from
Write
Pointer 1
group
group
12
10
8
7
5
6
3
4
Group
Read
Pointer
1
2
IMA Link Error Handling
For IMA operation, the RDAT is responsible for detecting Loss of IMA Frame defects (LIF),
Idle Cells on IMA Links, Loss of Cell Delineation defects (LCD), and DCB overruns/underruns
that contribute to Loss of Delay Synchronization (LODS). This information is forwarded to the
RIPP with the ICP messages for processing and reporting.
IMA Error/Maintenance State Machine (IESM)
A state machine is maintained for the LIF defect detection. This state machine is called the
IMA Error/Maintenance State machine [IESM]. The state diagram for the IESM is shown in
Figure 21. The RDAT maintains an IESM for each link. The LIF Defect state is the initial state
for this process, thus all links will initially come up in the LIF condition.
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2020889, Issue 2
65
PMC [ PMC-SIERRA, INC ]
