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PAD Message Set
Chapter 11
112
passed up from and down to the HDLC data-link layer. At each layer
below the application layer to the communication software, the data field
is passed up to the next higher layer where additional fields are defined.
Figure 11.1
PAD Format in Native Mode
DATA
(From Preceding Layer)
EXT
FF
SEL
x6
DATA
(From Preceding Layer)
CTL
ADDR
FCS
FLG
Data (Any Format)
238 Bytes Max.
Application Fields
PAD Fields
Native Fields
FLG
HDLC DataLink Fields
SSQ
TNS
USER
NODE
LINK
DATA
(from Preceding Layer)
STS
Native Fields
Figure 11.1 shows the Native-mode PAD message packet format
including the Native fields. The Native fields are those fields common to
all message transmissions in the Native mode. Here we describe these
Native fields.