All communication between a local and a remote station
is accomplished by the transmission of a packet that contains the
IEEE 802.3 headers and trailers as well as an encapsulated LLC link
protocol data unit (LPDU).
The Figure 1DLC8023
Frame Encapsulation figure (Figure 1)
illustrates the DLC8023 data packet: Figure 1. DLC8023 Frame Encapsulation
The IEEE 802.3 data packet consists of the following fields:
Item
Description
LPDU
LLC Link Protocol Data Unit
DSAP
Destination Service Access Point (SAP) address field
SSAP
Source SAP Address Field
CRC
Cyclic Redundancy Check or frame1-check sequence
m bytes
Integer value greater than or equal to 46 and less than or
equal to 1500
p bytes
Integer value greater than or equal to 0 and less than or
equal to 1496
Note: Preamble and CRC are added and deleted by the hardware adapter.
![This diagram shows the DLC8023 data packet containing the following: preamble (8 bytes), destination address (6 bytes), source address (6 bytes), LPDU length (2 bytes), LPDU, Pad (together with LPDU consist of m bytes), and CRC (4 bytes). A second line shows that LPDU consists of the following: DSAP address, SSAP address (together with DSAP address consist of 2 bytes), control field [1 (2) byte], and the information field (p bytes).](A0C0e410.jpg)