PM7311 pmc-sierra, PM7311 Datasheet - Page 79

• Manufacturer Part Number: PM7311
• Description: Freedm 84a1024l Assp Telecom Standard Datasheet
• Manufacturer: pmc-sierra

Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2021832, 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 25.
FREEDM 84A1024L ASSP Telecom Standard Product Data Sheet
Released
79