EVB-PIC24 WIZnet, EVB-PIC24 Datasheet - Page 97

• Manufacturer Part Number: EVB-PIC24
• Description: Development Boards & Kits - PIC / DSPIC W3150A+EVAL BOARD BASED ON PIC24
• Manufacturer: WIZnet

Specifications of EVB-PIC24

• Rohs: yes
• Product: Development Kits
• Interface Type: RS-232
• Data Bus Width: 16 bit
• Dimensions: 50 mm x 40 mm

QNAME, NAME, RDDATA Field are mostly composed as in <Fig 3.41: Example of QNAME Field
transformation of Question Section >. However, it can be compressed to reduce DNS Message Size.
Compression Scheme is expressed in 2 Byte. If the first byte, that is, the case where the upper 2 Bits
are ‟11,‟ it means the Label is compressed. It has the offset that is composed of 1
bits and 2
This offset is Offset of DNS Message and means the actual value of Label is located by the offset from the
starting point of DNS message. When Compress Scheme tries to reuse Domain Name that was already
used in DNS Message, relevant Domain Name sets the offset that is located in DNS Message as Indirect so
that it can reduce the size of DNS Message. <Fig 3.45> is an example of Compress Scheme of DNS
Message and its application.
The example of Compression Scheme of <Fig 3.45> shows DNS Message in case of “F.ISI.ARPA”,
nd
Byte
19
20
22
24
26
28
30
38
40
42
44
62
64 1
90
92
0
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0
1
1
<Fig 3.45: DNS Message Compression Scheme>
1
1
1
1
2
0
R
O
S
A
1
3
4
3
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
7
Offset
20
26
8
A
P
O
F
0
F
I
I
ST
15
Byte excluding upper 2
Message
DNS
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