PM7312 pmc-sierra, PM7312 Datasheet - Page 75

• 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
10.9.6
Frame Building
Frame or packet transfers across the Any-PHY interface require all the fragments of a frame/packet
to be present and in sequence before the transfer can occur. The frame building block monitors
incoming datagrams, and determines when a complete frame/packet has been received and is ready
for transfer. Examining status fields associated with datagrams that are entered in the 14 bit-sliding
window provides the necessary information. Multi-link sessions that are in-sequence require the
end-of-packet marker of incoming packets to be examined. When the frame builder detects the end
of packet marker, the CI is sent to the ingress queue manager. This signals that a frame/packet is
ready for transfer.
Out-of-sequence multi-link sessions require the frame builder to rapidly parse the fragment entries
in the data structure once the multi-link session returns to in-sequence state. This is required as
there may be a large number of fragments that are available for transmission once the session
becomes in-sequence (i.e. the outstanding fragment arrives and completes the sequence). To support
this, the frame builder maintains a block of status structures. Each block contains 128 status entries.
This enables the frame builder to review a large number of fragments once the session is in
sequence. If one or more complete frames are identified, the frame builder provides the associated
connection identifier to the ingress queue and the number of frames available.
Frame/Fragment Removal
The connection identifier selected by the ingress queue manager is used to extract the datagram at
the head of the connection queue. If this is the last entry in a secondary tier, the re-sequencing data
structure is returned to the free list of data structures. When the data is extracted, the corresponding
status bits (EOP, Active, BECN, FECN, DE) are cleared. The address field is cleared and a Null
pointer is placed in the location.
Ingress Queue Manager (IQM-12)
The ingress queue manager is in charge of transferring data from the external chunk buffer memory
to the Any-PHY interface logic. An overview of the ingress queue manager is presented in Figure
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FREEDM 32A1024L ASSP Telecom Standard Product Data Sheet
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