S/UNI-IMA-4 Telecom Standard Product Data Sheet
Released
The receive IMA sublayer performs IMA-frame delineation and stuff-cell removal. Based upon
the ICP cell information, the S/UNI-IMA-4 determines the differential delay between the links
within a group and applies the link and group state machine logic to coordinate the activation
and deactivation of groups and links with the far end. As cells are received, they are stored in an
external FIFO structure; this structure is based upon the IMA frame boundaries and the IMA
frame sequence number. When links or groups are determined to be active by the link and group
state machines, the data is played out to the Any-PHY/UTOPIA Interface at a constant rate to
mimic the existence of a single higher bandwidth physical link.
Once a group of links is established, links can be added or deleted from the group. Under
software control, the S/UNI-IMA-4 will perform all necessary steps to add or delete links from
previously established groups.
In order to aid diagnostics, a line side loopback and a UTOPIA side loopback are provided.
Also, an ICP cell trace feature is provided. When the ICP cell trace has been enabled for a
group, the S/UNI-IMA-4 will place ICP cells into a buffer that is accessible to the
microprocessor.
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2020889, Issue 2
28
PMC [ PMC-SIERRA, INC ]
