Chapter 7. Network Interface Cards
SOME OF THE MAIN TOPICS IN THIS CHAPTER ARE
Choosing a Hardware Bus Type 104 The Wired for Management (WfM) Initiative 110 Multi-Homed Systems 113 Load Balancing and Dual-Redundant Network Controllers 114 Software Drivers 114 IRQs and I/O Ports 116 Troubleshooting Network Cards 119
The network interface card (NIC) is the piece of hardware that links a computer or workstation to the network media. The standard Ethernet NIC resides at the Physical level of the OSI Seven-Layer Reference Model and is the device responsible for translating data into zeros and ones for transmission on the network media for the network using electricity or light. To send data to and from other computers, the NIC's driver software interfaces with the NIC's hardware elements and with the protocol stack that runs on the computer.
Although this chapter concentrates mainly on network adapters that are used on Ethernet networks, be aware that there are other cards that function differently. For example, cards made for ARCnet do more than provide the functions of the Physical layer of the OSI model. They also provide the data link functionality. Token-Ring cards also work differently than standard Ethernet cards. Host Bus Adapters (HBAs) used by Storage Area Networks also incorporate more functionality on the card, thus relieving the server of having to expend CPU cycles managing some of the protocol details. However, the general troubleshooting methods discussed in this chapter can usually be applied to all these card types.
Virtually all cards manufactured today support Plug and Play (PnP), although some older operating systems do notthat would make life too simple. So, although you might find that installing a new workstation or upgrading an old one with a new network adapter card is an easy task, this might not always be the case if you are working on older equipment. In this chapter, we'll look at the differences between card types and the items that are typically configurable for NICs. After that, we'll list some of the methods you can use to troubleshoot network problems when you suspect that the NIC might be the problem.
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