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ch10_handbook:data_file_interpretation [2014/04/13 18:41] bobch10_handbook:data_file_interpretation [2014/05/29 14:36] bob
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 +~~ODT~~
 ===== DATA FILE INTERPRETATION ===== ===== DATA FILE INTERPRETATION =====
  
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 ==== Overall Data Packet Organization ==== ==== Overall Data Packet Organization ====
  
- Overall data packet organization is shown in Figure 6-1. Data packets contain a standard +Overall data packet organization is shown below. Data packets contain a standard 
 header, a data payload containing one or multiple data messages, and a standard trailer. The  header, a data payload containing one or multiple data messages, and a standard trailer. The 
 standard header is composed of a required header, optionally followed by a secondary header.  standard header is composed of a required header, optionally followed by a secondary header. 
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  The packet header contains information about the data payload such as time, packet   The packet header contains information about the data payload such as time, packet 
 length, data type, data version, and other information. The layout of a Chapter 10 packet header  length, data type, data version, and other information. The layout of a Chapter 10 packet header 
-is shown in Figure 6-2FIXME+is shown below.
  
 <code> <code>
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  The optional secondary header is used to provide an absolute time (i.e. clock time) stamp   The optional secondary header is used to provide an absolute time (i.e. clock time) stamp 
 for data packets. The secondary header time format can be interpreted several ways. The  for data packets. The secondary header time format can be interpreted several ways. The 
-specific interpretation is determined by the value of header Flag Bits 2 and 3. The structure in  +specific interpretation is determined by the value of header Flag Bits 2 and 3. The structure below 
-Figure 6-3 is used when secondary header time is to be interpreted as a Chapter 4 format value  +is used when secondary header time is to be interpreted as a Chapter 4 format value  
-(Flag Bits 3-2 = 0). The structure in Figure 6-4 is used when secondary header time is to be +(Flag Bits 3-2 = 0). The following structure is used when secondary header time is to be 
 interpreted as an IEEE 1588 format value (Flag Bits 3-2 = 1). interpreted as an IEEE 1588 format value (Flag Bits 3-2 = 1).
  
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 when there are no more data messages to read.  when there are no more data messages to read. 
    
- Intra-packet headers, when they are present, typically contain one, or sometimes more +Intra-packet headers, when they are present, typically contain one, or sometimes more 
 than one, time stamp as well as other information about the data message that follows.  than one, time stamp as well as other information about the data message that follows. 
-Commonly used structures for intra-packet time data are shown in Figure 6-5, Figure 6-6, and  +Commonly used structures for intra-packet time data are shown in the three figures below. 
-Figure 6-7. These three time structures will be referenced in most of the data format descriptions +These three time structures will be referenced in most of the data format descriptions 
 that follow.  that follow. 
  
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 multicast addresses.  multicast addresses. 
    
- Multicast data is filtered by the Ethernet controller hardware, only passing subscribed +Multicast data is filtered by the Ethernet controller hardware, only passing subscribed 
 packets to the software driver for decoding. This improves performance under high network  packets to the software driver for decoding. This improves performance under high network 
 traffic loads. Ethernet controllers only have a limited number of multicast addresses they can  traffic loads. Ethernet controllers only have a limited number of multicast addresses they can 
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 Ethernet technologies support larger jumbo frames.  Ethernet technologies support larger jumbo frames. 
    
- Chapter 10 data packets are sent in a UDP/IP packet by prepending a UDP transfer  +Chapter 10 data packets are sent in a UDP/IP packet by prepending a UDP transfer header to the UDP data payload. Chapter 10 data packet(s) smaller than the 32k maximum size will prepend the non-segmented UDP transfer header shown below
-header to the UDP data payload. Chapter 10 data packet(s) smaller than the 32k maximum size  +
-will prepend the non-segmented UDP transfer header shown in Figure 6-54. A Chapter 10 data  +
-packet larger than the 32k maximum size will need to be segmented before transmission, and  +
-will prepend the segmented UDP transfer header shown in Figure 6-55. IPv6 supports large data  +
-packets, negating the need for segmented data packets+
  
 <code> <code>
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 </code> </code>
 <html><center><b>UDP Transfer Header, non-segmented data</b></center></html> <html><center><b>UDP Transfer Header, non-segmented data</b></center></html>
 +
 +A Chapter 10 data packet larger than the 32k maximum size will need to be segmented before transmission, and 
 +will prepend the segmented UDP transfer header shown below. IPv6 supports large data packets, negating the need for segmented data packets. 
  
 <code> <code>
ch10_handbook/data_file_interpretation.txt · Last modified: 2014/07/16 15:18 by bob

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