EVB-B1+ WIZnet, EVB-B1+ Datasheet - Page 89

• Manufacturer Part Number: EVB-B1+
• Description: Development Boards & Kits - ARM W3150A+EVAL BOARD BASED ON AVR
• Manufacturer: WIZnet

Specifications of EVB-B1+

• Rohs: yes
• Product: Evaluation Boards
• Interface Type: RS-232, SPI
• Operating Supply Voltage: 3.3 V, 5 V
• Data Bus Width: 8 bit
• Dimensions: 50 mm x 40 mm
• Processor Series: ATmega128

<Fig 3.37: Recode Resources Format>
Header Section of DNS Message holds type of Message, DNS Query type, and count information on
variable length section.
In <Fig 3.35: Header Section Format>, QR field gets 0 when DNS Message is a request from Resolver to
Name Server and gets 1 when it’s from Name Server to Resolver. Opcode Field gets 0 when it queries
Domain Name as IP Address and gets 2 when it queries Name Server status.
QDCOUNT, ANCOUNT, NSCOUNT, and ARCOUNT Field, count information for variable length, represent
Block Count that is composed of Question, Answer, Authority, and additional section. Question section is
made of blocks shown in <Fig 3.36: Question Section Format>. Answer, Authority, and Additional Sections
are composed of blocks shown in <Fig 3.37>.
For example, if QDCOUNT is 1, ANCOUNT is 10, NSCOUNT is 10, and ARCOUNT is 10 then Question
Section is composed of block 1 of <Fig 3.36: Question Section Format>. Answer, Authority, and Additional
Section are composed of 10 blocks shown in <Fig 3.37>.
NAME of <Fig 3.37>, QNAME Filed of <Fig 3.36> and RDDATA Field also get variable lengths. QNAME and
NAME are variable length fields which are composed of <Fig 3.36> Format and they process each field.
RDDATA, variable length field, processes using the data length of RDLENGTH Field.
For further details, refer to RFC1034 and RFC1035
DNS Message is operated by Data Type defined in <Table 3-38>. Refer to “inet/dns.h”
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