MT92220BG Zarlink Semiconductor, MT92220BG Datasheet - Page 78

• Manufacturer Part Number: MT92220BG
• Description: Description = 1023 Channel Voice Over IP/AAL2 Processor ;; Package Type = Epbga ;; No. Of Pins = 608
• Manufacturer: Zarlink Semiconductor

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8.3.7
The Sequence Number is incremental and is incremented and generated for all packets regardless of their source.
This means that HDLC and CPU packets that generate an RTP header will have their Sequence Number thrown
out and replaced by the one generated by this structure. The Sequence Number Insert bit indicates whether or not
the sequence number will be inserted by the chip for HDLC and CPU-sourced packets. If this bit is '0', then the
sequence number coming from the packets will be kept. Note that in this case, no PCM packets can be generated
on this connection (i.e. ALL sequence numbers will be externally generated).
8.3.8
The Transmitted Packet Count is a 16-bit counter indicating the number of packets that have been generated on
this connection since its startup. The Transmitted Octet Count is a 32-bit counter of the number of payload bytes
generated in packets on this connection. This only includes payload, but it will also include any RTP headers
present in CPU or HDLC packets that are seen by the system as payload. These two fields allow good diagnostic of
the connection’s bandwidth on IP.
For RTCP support and diagnostics, each time a packet is transmitted, the first 12 bytes of the packet payload (in the
case of HDLC/CPU packets), or the first 12 bytes of RTP header for PCM packets, are copied into external memory.
For HDLC/CPU channel carrying RTP, the first 12 bytes will represent the mandatory fields of the RTP header. With
this information, RTCP packets can be generated without requiring communication between the host on which the
MT92220 is running and the source of the HDLC data stream.
8.3.9
The RTD field (RouTing Destination) indicates where this packet will be destined in the network interface. In most
applications it will be set to transmit packets to port A, but the field allows flexibility by allowing the possibility of
internal loopback, sending to port B, or other destinations.
Sequence Number
Transmitted Packet Count
RTD
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