Network Adapter Cards (NICs)


INTRODUCTION TO NETWORK ADAPTER CARD

First of all, have a look below on these terms:

1. Network Adapter Card
2. Network Interface Card
3. NIC Card
4. Ethernet Card
5. Network Card
6. Network Adapter

These all terms are having the same meaning: A card, which links a personal computer with the network cabling system.

We will use a term: "Network Adapter Card".

The network adapter card fits into one of the PC's expansion slots. The card has one or more user-accessible ports to which the network-cabling medium is connected.

Like other hardware devices, a network adapter card has a 'driver', a software component that manages the device. The network adapter card driver serves a crucial role in the networking architecture. Adapter card drivers inhabit the Data Link layers of the OSI model (you may want to review my article: "The OSI Reference Model"), or more specifically, the Media Access Control (MAC) sublayer of the Data Link layer. A network adapter card driver sometimes is also called a MAC driver. The NDIS and ODI standards (in the Binding sheet under the Network Applet in Control Panel) provide a uniform interface for the adapter card driver, enabling one adapter to support multiple protocols and making one protocol accessible to multiple adapters.

The network adapter card's built-in ROM (read only memory) performs the functions of the Logical Link Control sublayer of the OSI Data Link layer.

The network adapter card and its accompanying software and firmware perform several roles. Microsoft identifies the following roles for the network adapter card:

1. Preparing data for the transmission medium
2. Sending Data
3. Controlling the flow of data from the PC to the transmission medium

Of course, the network adapter must also play these roles in reverse, receiving data from the network and converting that data to the form necessary for the local system.

PREPARING DATA

Data travels on the network in serial form (one bit at a time). Inside the PC, however, data moves along the bus in parallel form (8, 16, or 32 bits at a time). The network adapter card, therefore, must convert the parallel data from the bus into the serial form required for network transmission. If the card receives data from the local system, it can transmit that data to the network. The data then is stored in a memory buffer on the adapter card until the card can catch up.

Because the network adapter card's software and firmware participate in the Data Link layer of the protocol stack, they are responsible for contributing data0link header information, such as the network adapter card's physical address.

The copyright of the article Network Adapter Cards (NICs) in Local Area Networks is owned by Muhammad Ahsan. Permission to republish Network Adapter Cards (NICs) in print or online must be granted by the author in writing.

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