PM7312 pmc-sierra, PM7312 Datasheet - Page 74

• Manufacturer Part Number: PM7312
• Description: Freedm 32a1024l Assp Telecom Standard Datasheet
• Manufacturer: pmc-sierra

Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2021833, Issue 2
Figure 24 Elements in the Re-sequencing Block
The incoming sequence number is compared with the expected sequence number (head + 1). If the
two are equal, the datagram is in sequence. The end of packet marker is examined to determine if a
complete frame/packet is available for transfer. This is signaled to the frame builder block. A
session that was previously out-of-sequence may have a backlog of frames/packets ready for
transfer once the in-sequence frame/packet is received. This is signaled to the frame assembly
block.
If the sequence numbers do not align, and the multi-link session was previously in sequence, a re-
sequencing operation is triggered and the datagram is logically placed in the re-sequencing buffers.
The datagram is removed from the re-sequencing buffers when the re-sequencing operation has
correctly re-sequenced the datagrams. These datagrams are passed to the frame builder of the
ingress queue manager depending on the mode of transfer.
Frames/packets without sequence numbers use the same data structures to queue frames. However
the re-sequencing and frame detection logic is not required. FRF12 fragmentation (single link
sequencing for QOS reasons) and the potential equivalent for PPP are supported via the structures
in place.
In order to preserve integrity of the data structures in the event of a soft error the addresses are
protected by ECC capable of detecting 2 and correcting 1 error.
location = lsb_record_offset + (Seq# mod 128)
Fragment to be added
Location = channel_offset + (Seq#/128)
1st tier (128 entries)
2nd tier (128 entries)
FREEDM 32A1024L ASSP Telecom Standard Product Data Sheet
Datagram to be added
Pointer to head of fragment
Frag chunk 0
Pointer to second tier
data structure
Frag chunk 1
Frag chunk 2
Frag chunk N
Released
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