NICs (network interface cards, also called network adapters or network cards) enable a workstation, server, printer, connectivity device, or other node to receive and transmit data over thenetwork media. NICs contain a transceiver, which transmits and receives data signals. As youlearned in Chapter 2, NICs belong to both the Physical layer and Data Link layer of the OSImodel because they issue data signals to a wire or into the air and assemble or disassembledata frames. They also interpret physical addressing information to ensure data is deliveredto its proper destination. In addition, they perform the routines that determine which nodehas the right to transmit data over a network at any given instant—CSMA/CD on anEthernet network, for example.Advances in NIC technology are making this hardware smarter than ever. Many NICs canalso perform prioritization, network management, buffering, and traffic-filtering functions.On most clients, NICs do not, however, analyze information added by the protocols in Layers3 through 7 of the OSI model. For example, they could not determine whether the frames theytransmit and receive use IP datagrams or a different Layer 2 protocol. Nor could theydetermine whether the Presentation layer has encrypted the data in those packets.Because NICs are common to every networking device and every network, knowing as muchas possible about them will prove useful. The following section describes several types ofNICs, their functions, and their features.Types of NICsAs you design or troubleshoot a network, you will need to know the characteristics of theNICs used by its clients, servers, and connectivity devices. For example, when you order aswitch, you’ll have to specify the network interfaces that match your network’s speed andcabling connectors. NICs come in a variety of types depending on the following:● Access method (for example, Ethernet)● Network transmission speed (for example, 100 Mbps versus 1 Gbps)● Connector interfaces (for example, RJ-45 versus SC)● Number of connector interfaces, or ports1.22.6NICs (Network Interface Cards) 243Copyright 2013 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to
đang được dịch, vui lòng đợi..
![](//viimg.ilovetranslation.com/pic/loading_3.gif?v=b9814dd30c1d7c59_8619)