PM7312 pmc-sierra, PM7312 Datasheet - Page 73

• 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
Re-sequencing List Addition
Datagrams that have not been discarded are entered in the re-sequencing list. The resequencing
algorithm in FREEDM 32A1024L supports the worst case number of packets on a multi-link
bundle of T1/E1s that have experienced an intra skew delay of 100ms. To support that a subset of
the 24-bit sequence number space is supported. Fourteen of the 24 bits are used for re-sequencing.
All 12 bits are used when supporting 12 bit sequence numbers. On initialization, the Head Sequence
number is set to the sequence number of the first fragment received. Subsequent sequence numbers
are declared as USN if they are within a small range prior to the Head Sequence number. Arriving
datagrams are placed in the sliding window with an offset determined by distance (difference)
between the sequence number at the head of the window and the current sequence number.
Figure 23 14-bit Sliding Window Used for Re-sequencing
The sliding window (Figure 23) is realized as a two tiered data structure (Figure 24). This is done to
reduce the memory required to support 16K simultaneous multi-link sessions. The initial tier is
present for all multi-link sessions. Secondary tiers are added and removed when needed. The
number of second tiers is limited. Enough are provided to support the simultaneous resequencing on
all multi-link sessions.
Fragment to be added:
Location = channel_offset + (seq# - head_seq#)
Apply a sliding window across the 24 Sequence number space
Insert elements based on an offset of the head sequence number.
14 bits of the sequence number
FREEDM 32A1024L ASSP Telecom Standard Product Data Sheet
Unpopulated sequence # has
Null tag on it.
Head Seq#
Released
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