PM7312 pmc-sierra, PM7312 Datasheet - Page 61

• 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
10.3.2
skew between the physical links in the multi-link bundle, re-sequencing is essential to enabling
multi-link protocols. Both 12 and 24 bit sequence numbers are supported for PPP while the 12 bit
FRF.12 format is supported for FR.
The incoming sequence number is compared with the expected sequence number. If the two are
equal, the datagram does not need to be re-sequenced and is logically passed to the ingress queue or
the packet/frame builder depending on the style of data transfer (packet or fragment) requested for
the Any-PHY channel.
If the sequence numbers do not align, 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 or the ingress queue manager depending on the mode of
transfer. In addition to re-sequencing, a loss detection algorithm detects lost datagrams.
When the Any-PHY transfer is frame/packet based, the frame builder constructs complete frames or
packets from the datagrams that have been constructed by the fragmentation builder. These
complete frames/packets are transferred to the ingress queue manager.
The ingress queue manager retrieves the frame/packet from the external chunk buffer memory and
transfers it to the upstream system device via the Any-PHY interface.
Egress Path
Figure 15 shows the elements and data transformations that occur as data traverses the FREEDM
32A1024L from the Any-PHY to the SBI interface.
Figure 15 Egress Data Flow
Full packets must be transferred from the upstream device to the FREEDM 32A1024L via the Any-
PHY interface. When supporting a multi-link bundle, the Any-PHY channel is mapped to multiple
HDLC channels. The transmit fragmentor will fragment packets/frames and distribute the fragments
across all the HDLC channels in the multi-link bundle applying the appropriate sequence number to
each of the fragments. The fragmentation size is programmable on a per connection basis. The
Bitstreams per link
INSBI336
Bytes per HDLC Channel
Channel-
De-
izer
Block per HDLC Channel
FREEDM 32A1024L ASSP Telecom Standard Product Data Sheet
HDLC
Partial
Packet
Processor
Egress
Queue
Manager
TFRAG Builder
ANY
PHY
I/F
Released
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