The role of the network Adapter card it to:
Prepare data from the computer for the network cable
Send the data to another computer
Control the flow of data between the computer and the cabling system
NIC's contain hardware and firmware (software routines in ROM) programming that implements the
Logical Link Control and
Media Access Control
functions of the Data Link layer of the OSI
Preparing Data
data moves along paths in the computer called a BUS - can be 8, 16, 32 bits wide.
on network cable, data must travel in a single bit stream in what's called a serial transmission (b/c on bit follows the next).
The transceiver is the component responsible for translating parallel (8, 16, 32-bit wide) into a 1 bit wide serial path.
A unique network address or MAC address is coded into chips in the card
card uses DMA (Direct Memory Access) where the computer assigns memory space to the NIC
if the the card can't move data fast enough, the card's buffer RAM holds it temporarily during transmission or reception of data
Sending and Controlling Data
The NICs of the two computers exchanging data agree on the following:
Maximum size of the groups of data being sent
The amount of data to be sent before confirmation
The time intervals between send data chunks
The amount of time to wait before confirmation is sent
How much data each card can hold before it overflows
The speed of the data transmission
