What is a network card called?

Networks

Jeremy Faircloth, in Enterprise Applications Administration, 2014

Network Interface Card

An NIC is the core piece of hardware used for networking connectivity. While traditionally associated with PCs, laptops, and servers, NICs can exist in almost any networked device including printers, telephones, and scanners. In some networking hardware, such as switches used for network storage arrays, there are replaceable modules that allow for the use of different connection types. These modules are technically NICs as well.

As we discussed previously in this chapter, every NIC has a MAC address in the Ethernet or Token Ring topologies. This unique hardware address defines how the NIC is identified to ensure that the data gets to the correct system. The MAC address can usually be modified when needed, but all NICs will have a preassigned MAC address associated with the NIC. Depending on the way that configuration management is handled in the enterprise, these MAC addresses may be set following a specific standard, recorded for inventory purposes, or potentially used to determine whether or not a specific system should be allowed on the network. This security function is most typically associated with wireless networks where MAC address filtering is a standard configuration option.

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Understanding the Technology

Littlejohn Shinder, Michael Cross, in Scene of the Cybercrime (Second Edition), 2008

The Role of the NIC

The network interface card (NIC) or network card is the hardware device most essential to establishing communication between computers. Although there are ways to connect computers without a NIC (by modem over phone lines or via a serial “null modem” cable, for instance), in most cases where there is a network, there is a NIC for each participating computer.

The NIC is responsible for preparing the data to be sent over the network medium. Exactly how that preparation is done depends on the medium being used. Most networks today use Ethernet. Ethernet was developed in the 1960s with specifications developed by Digital, Intel, and Xerox (governed by IEEE 802.3 standards). It uses a method of accessing the network called Carrier Sense Multiple Access/Collision Detection (CSMA/CD), in which each computer monitors the network to ensure that no one else is sending data along the same line of cabling. If two computers send data at the same time, it causes a collision that's detected by the other workstations, and the computers will wait a random time interval to send the data again.

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Domain 2

Eric Conrad, ... Joshua Feldman, in CISSP Study Guide (Second Edition), 2012

Managed, master, ad hoc, and monitor modes

802.11 wireless NICs can operate in four modes: managed, master, ad hoc, and monitor mode. 802.11 wireless clients connect to an access point in managed mode (also called client mode). Once connected, clients communicate with the access point only; they cannot directly communicate with other clients.

Master mode (also called infrastructure mode) is the mode used by wireless access points. A wireless card in master mode can only communicate with connected clients in managed mode.

Ad hoc mode is a peer-to-peer mode with no central access point. A computer connected to the Internet via a wired NIC may advertise an ad hoc WLAN to allow Internet sharing.

Finally, monitor mode is a read-only mode used for sniffing WLANs. Wireless sniffing tools such as Kismet or Wellenreiter use monitor mode to read all 802.11 wireless frames.

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Network Troubleshooting

Naomi J. Alpern, Robert J. Shimonski, in Eleventh Hour Network+, 2010

Troubleshooting the Physical Layer

When troubleshooting the physical layer, you'll be most concerned with NICs, network cables, and hubs.

Troubleshooting the NIC

Verify that the NIC does match the media access type

Verify that the NIC does have the correct connector for the cable your network uses

Verify that the NIC driver is properly installed and updated

Troubleshooting cables

Verify that the cable meets the appropriate specifications for the network

Verify that the cable is not broken or damaged

Verify that the maximum allowable segment length for the cable type in use has not been exceeded to prevent attenuation

For coax networks, ensure the network is following the restrictions imposed by the 5-4-3 rule

Troubleshooting the installation of the TCP/IP stack

Ensure the protocol is loaded properly by pinging the loopback address of 127.0.0.1

Verify that the proper addressing is configured on the NIC

Troubleshooting repeaters and hubs

For active hubs, ensure that the device has power

Ensure that the computers’ NICs are communicating with the device by checking status lights on active hubs

Ensure that devices are installed in accordance with the Institute of Electrical and Electronic Engineers (IEEE) specifications for the particular network architecture

Ensure that all ports on the device are functional by checking for a green LED lights when you attach a computer to the port through a network cable

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URL: https://www.sciencedirect.com/science/article/pii/B9781597494281000096

MCSE 70-293: Planning, Implementing, and Maintaining a High-Availability Strategy

Martin Grasdal, ... Dr.Thomas W. ShinderTechnical Editor, in MCSE (Exam 70-293) Study Guide, 2003

Network Fault-Tolerance Solutions

One area of component failure is the network interface. If a system has one interface to a network, and a component of that interface fails (the switch, the cable, or the NIC), the whole interface fails. As a result, it is a good idea to build redundancy into your network interfaces.

Several manufacturers sell NICs that have two or more ports. Using the appropriate drivers, these cards usually support either a failover configuration or a load-balanced configuration, which work as follows:

Failover Keeps one port idle and waiting, while the other port(s) handle communications. If a component of that interface fails, the idle port comes online and takes over for the failed port. A failover configuration can be used with switches or nonswitched network hubs.

Load-balanced configuration Uses multiple ports simultaneously and spreads the communication load among the ports. In the event of an interface failure, the communications load is reassigned to the remaining active ports. A load-balanced configuration yields higher availability and performance but can be used only in conjunction with higher-end intelligent switches.

Some network topology issues can affect network availability as well. When designing a network, keep in mind all of the potential failure points, including routers, switches, bridges, and wide area network (WAN) components.

In all but the smallest networks, it is a good idea to have redundant functionality for critical services. If you are using AD, make sure that you have more than one domain controller and DNS server. If you are using WINS, create a secondary WINS server and have it replicate with the primary WINS server. If you are using DHCP, create a secondary DHCP server on each subnet and configure each with the appropriate scopes. Following these guidelines will ensure continued operation of these services in the event of failures.

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URL: https://www.sciencedirect.com/science/article/pii/B9781931836937500129

Installing Sniffer Pro

Robert J. Shimonski, ... Yuri Gordienko, in Sniffer Pro Network Optimization and Troubleshooting Handbook, 2002

Configuring Network Interfaces and Drivers

What is a network card called?

Sniffer Pro requires a NIC that can operate in promiscuous mode.

What is a network card called?

Default NDIS drivers do not provide the performance and stability that enhanced NAI drivers do. Enhanced NAI drivers are available only for certain NICs as recommended by NAI.

What is a network card called?

NAI's enhanced drivers are designed to pass physical layers to the Sniffer Pro software.

What is a network card called?

The Fast Ethernet Full Duplex Pod can be used to capture full-duplex traffic off the network.

What is a network card called?

For highest levels of capture performance, maximize the amount of physical memory and processor speed on the Sniffer Pro system. You can also turn off the real-time expert as well as router expert capabilities if you do not need these features.

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URL: https://www.sciencedirect.com/science/article/pii/B978193183657950006X

Local Area Networks

Judy Wynekoop, in Encyclopedia of Information Systems, 2003

VIII.A. Network Interface Cards

Devices are connected to the medium by a NIC, also called a network adapter card or network card. The network adapter may also be found on a computer's motherboard. The NIC contains electrical circuitry implementing data link and physical layer standards, including a port to connect to the LAN's medium. Each communicating device (node) on a LAN must have at least one NIC. If a data frame is addressed to the computer, the NIC stores a copy of the frame in a buffer and interrupts the CPU.

A NIC supports specific wiring standards and connectors. Some NICs, called “combo cards,” contain ports for multiple connectors. The actual NIC/network connection depends on the network architecture. Sometimes the NIC contains all the necessary interface circuitry and attaches directly to the network (e.g., 10/100BaseT); and other architectures (e.g., 10Base5) require a drop cable from the NIC in the computer to another electrical component, the transceiver, which attaches to the network.

Network operating systems communicate with the NIC through NIC driver software called Network Data-Link Interface Specification (NDIS, developed by Microsoft and 3COM) or Open Data-Link Interface (ODI, developed by Novell and Apple). Most NICs today support both NDIS and ODI.

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Introduction to Networking

Dale Liu, ... Luigi DiGrande, in Cisco CCNA/CCENT Exam 640-802, 640-822, 640-816 Preparation Kit, 2009

NIC

As described earlier, the NIC is used to connect the computer and media together with the network. There are two types of network cards available for 802.5 Token Ring networks. The first is a 4 MBps card and the other supports both 4 MBps and 16 MBps. A lot of people think that Token Ring is not in common use today, as Ethernet (IEEE 802.3) is installed in most office LANs, but in hospitals and other medical facilities 802.5 (Token Ring) is preferred when large images (like X-rays) have to be moved from the diagnostic network to the physician network.

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URL: https://www.sciencedirect.com/science/article/pii/B9781597493062000051

Security Guidance for ICA and Network Connections

Tariq Bin Azad, in Securing Citrix Presentation Server in the Enterprise, 2008

Multihomed servers

One consideration when choosing a NIC is whether to make a machine multihomed or not. A machine is multihomed when it contains two or more NICs that each connect to a network segment. These can be separate segments, or the same segment in the case of multihoming a machine for redundancy or speed issues. Multihomed machines can act as routers if an actual router is not available, but this will eat up the Central Processor Unit (CPU) to provide the routing service. Multihoming a XenApp server can be implemented for several reasons, which include:

Servers that require redundant access

Servers that require out of band management access (remote administration only)

Servers that require a separate backup network

Configuration of a private internal network

Servers that require communication with resources outside the internal network.

Network bottlenecks can occur anytime an application that is executed by XenApp Server doesn't actually exist on the server itself. For instance, Microsoft Word will typically install locally on the XenApp Server, but the data normally exists somewhere else on the network. This is even more true for client-server applications such as PeopleSoft or SAP. While the bandwidth used by the sessions the server is hosting is relatively low, the network requirements for those sessions will be substantially higher. There are several ways to address this issue:

Teamed cards to increase available bandwidth

Collocation of the application and data on the Presentation Server

Multihomed servers with network connects that separate session bandwidth from application bandwidth

Teaming network cards for redundancy is almost always a good idea. By aggregating multiple network cards together, their “physical” bandwidth can be logically totaled to provide for more “pipe.” Most network cards today support teaming (in various forms), and in some cases the ability to team dissimilar network cards (such as a 10/100Mbps card with a 1Gbps card) if the need arises. We recommend that you always attempt to team identical cards to reduce the complexities and supportability issues that could arise otherwise.

Placing the application and data on the XenApp Server will certainly decrease the amount of traffic required to service the user request, thus eliminating the network as the potential bottleneck. However, this action means we have indirectly created a single point of failure for access to this application. If the data is located on a single XenApp Server, we will most likely not be able to “load balance” the application across the farm; therefore, this option isn't really a viable solution except in certain circumstances.

The last option of multihoming our XenApp Server presents many opportunities to increase performance and in a more limited way to increase fault tolerance. The concept of multihoming servers of all kinds has been around the networking world nearly as long as the network itself! Multihomed servers presented solutions to allow for fault tolerance, increase bandwidth, and in some cases, “private” networks for backup and authentication services. However, historically, XenApp's ancestors have had issues with multiple “paths” to a server. In the past, a Citrix server may inadvertently direct a user session to the “wrong” card in a multihomed server scenario, thus creating a denial of service .This problem has been long since fixed, so today we can discuss the benefit of multihoming our XenApp Servers to improve quality of service (QoS).

By multihoming your XenApp Servers you can segment our session traffic from our data traffic (and possibly the authentication and backup traffic as well). Placing two “legs” or “routes” to the network also can provide some measure of fault tolerance for access to the specific XenApp Server (although typically this is not as reliable or automatic as teaming).The situation arises due to the nature of application and network access. Let us consider the following scenario. Suppose you have a single XenApp Server that has a single NIC for all user sessions and network data access. The server is servicing 50 user sessions. The applications are all well behaved with the exception of your in-house database system for order tracking. When the application running on the XenApp Server (or client workstation) accesses the database for queries, large amounts of traffic are generated between the server and the database until the request is fulfilled. This translates into periods of slowness for the other user sessions on the server (even though the CPU, memory, and disk performance may be fine).Why? The answer is that all the user sessions and the application data access are contending for the same network link. Consider separating the user sessions and database access onto two separate network cards. Figure 8.4 demonstrates this concept of isolating the “data” network from the “session” network.

What is a network card called?

Figure 8.4. Multihomed XenApp Server

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MCSA/MCSE 70-291: Reviewing TCP/IP Basics

Deborah Littlejohn Shinder, ... Laura Hunter, in MCSA/MCSE (Exam 70-291) Study Guide, 2003

Network Interface Hardware/Software

The network interface is established through the Network Interface Card. Each type of NIC uses a different type of connector to connect to the physical medium. The connector types are delineated in the IEEE 802 specifications. Each network technology is delineated in its own section of the 802 specification, as described previously. Most significantly, Ethernet is defined in 802.3, Token Ring in 802.5, and Wireless Networking in 802.11.

The NIC employs both hardware and software in connecting the device to the network media. The TCP/IP Network Interface layer defines protocols used by the NIC to receive, assemble, address, and transmit. For example, most Ethernet networks in use today employ an Ethernet NIC, which, among other things, uses CSMA/CD to control media access. The most common type of Ethernet NIC uses a Category 5 or greater unshielded twisted pair cable (typically referred to as UTP CATS, CAT5e, or CAT6) with specified pin connections. In some cases, Ethernet is still deployed over thin (1/4 inch diameter) or thick (1/2 inch diameter) coaxial cable. Ethernet can also be deployed over fiber optic cable. Regardless of the cable type, Ethernet networks use the same contention-based access control method.

UTP cabling connects to the NIC via an RJ-45 modular plug and jack (similar to a large phone jack), and thin coax (thinnet) connects via a BNC connector (Bayonet Neill Concelman, after its twist-on style and the two men who invented it) shaped like a T. Thick coaxial (thicknet) is connected via a vampire tap (a metal pin that penetrates the cable) to an external transceiver, which in turn connects to the NIC. Other types of Ethernet NICs have the transceiver built onto the NIC itself. Some NICs, called combo cards, have connectors for more than one type of cable.

The Ethernet NIC is also responsible for receiving/sending and assembling/disassembling data to and from the network connection. The Network Interface layer in the DoD model encompasses the functions of the OSI model’s Physical and Data Link Control layers and controls media access and the assembly/disassembly of data at the lowest level of the hierarchy.

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Is Ethernet a network card?

Also called a "network interface card" (NIC), an Ethernet adapter is a card that plugs into a slot on the motherboard and enables a computer to access an Ethernet network (LAN). In the past, desktop computers always used cards.

What is an example of a network card?

An example of a card is a driver's license or a credit card.

Where is the network card in a computer?

Where is a network card located in a computer? In a desktop computer, the network card is most often located near the USB ports on the back if it's an onboard version. If it's a separate network card expansion card (not onboard), it usually is on the back of the computer, near the bottom, taking up a PCI slot.