UNIT STRUCTURE Network Interface Card (NIC)

Basic of NIC and its operation, Principles of NIC Configuration, Special purpose NIC Wireless adapters and Remote Boot adapters, Device Driver Software

Equipment Perspective

Repeater, Bridge, Router, Gateways, Protocol Specific Devices, Router Technology Multiplexer, Network Switches

LEARNING OBJECTIVES

After going through this unit, you should be able to:

Discuss benefits of network management and planning Understand the fundamentals of data communication Explain how networking media, devices works together to provide data networking

services Understand necessity for networking standards, policies and procedures, and

documentation Troubleshoot your network with a structured approach Discuss types of specialized equipment and other resources available for troubleshooting

UNIT 5 NETWORKING DEVICES

NETWORK INTERFACE CARD (NIC)

A network interface card (NIC) is a computer circuit board or card that is installed in a computer

so that it can be connected to a network.

Personal computers and workstations on a local area network (LAN) typically contain a network

interface card specifically designed for the LAN transmission technology, such as Ethernet or

token ring. Network interface cards provide a dedicated, full-time connection to a network. Most

home and portable computers connect to the Internet through as-needed dial-up connection. The

modem provides the connection interface to the Internet service provider.

BASIC OF NETWORK INTERFACE CARD

• For any computer, a network interface card (NIC) performs two crucial tasks

– Establishes and manages the computer’s network connection

– Translates digital computer data into signals (appropriate for the networking

medium) for outgoing messages, and translates signals into digital computer data

for incoming messages

• NIC establishes a link between a computer and a network, and then manages that link

• NICs also manage transformations in network data’s form

– The computer bus has series of parallel data lines

• Parallel transmission

• For nearly all forms of networking media, signals traversing the media consist of a linear

sequence of information that corresponds to a linear sequence of bits of data (serial

transmission)

• To redistribute serial data to parallel lines (and vice versa), one of the most important

components on a NIC is memory, which acts as a buffer

OPERATIONS OF NETWORK INTERFACE CARD

The main function of a network adapter is to pick up the data, send it to network cables from the

computer, divide the data into appropriate packets and send them to the network so as to allow

the computer to access that network. Each NIC card has a ROM chip that contains a unique

number, the media access control (MAC) Address that is permanent. The MAC address

identifies the device uniquely on the LAN.

Network interface cards, usually referred to as NICs, act as the physical interface or connection

between the computer and the network cable. The cards are installed in an expansion slot in each

computer and server on the network.

After the NIC has been installed, the network cable is attached to the card's port to make the

actual physical connection between the computer and the rest of the network.

Some Imp. Operation of the NIC is given below:

1) Prepare data from the computer for the network cable.

2) Send the data to another computer.

3) Control the flow of data between the computer and the cabling system.

4) Receive incoming data from the cable and translate it into bytes that can be understood by the

computer's central processing unit (CPU).

PRINCIPALS OF NIC CONFIGURATION:

• Match NIC to slot on PC or external connection such as USB

• Microsoft introduced Plug and Play (PnP) architecture with Windows 95

– Defines a set of configuration protocols so that a computer can communicate with

its peripherals during the power-on self-test (POST) sequence and auto-negotiate

a working configuration

• NIC configuration involves modifying settings

– Interrupt request line (IRQ)

– Base I/O port

– Base memory address

SPECIAL PURPOSE NIC WIRELESS ADAPTERS AND REMOTE

BOOT ADAPTERS:

In addition to straightforward network adapters, several types of cards deliver specialized

capabilities. They include interfaces for wireless networks, as well as a feature for so-called

diskless workstations (“thin clients”), which must access the network to load an OS when they

boot these cards are said to support remote booting or remote initial program load.

Wireless Adapters

• Wireless interfaces usually incorporate some or all of the following components:

– Indoor antenna and antenna cable

– Software to enable the adapter to work with a particular network environment

– Diagnostic software

– Installation software

• Wireless NICs are commonly used with an access point to add wireless elements to an

existing LAN

• Select: speed, wireless standard, other (e.g., security)

Fig.-Wireless Card

Remote Boot Adapters

• The network must be the source of access to the programs needed to start a diskless

workstation

– Some NICs include a chip socket for a special bit of circuitry called a Boot

PROM, which is referred to as preboot execution environment (PXE) compliant

– Remote boot adapters offer several advantages

• Cost savings because no hard drive is required

• Improved reliability (hard drives are a common source of problems)

• Security is increased (no sensitive data can be stored on the computer)

• Virus attacks are useless

Device Driver Software

NIC DRIVER CONFIGURATION:

• Device driver: small, specialized program that represents a device to an OS and manages

communications between the OS and NIC

• Incorrect/poorly written drivers can have negative impact on performance or prevent PC

from booting

• Major vendor standards for drivers

– Network Device Interface Specification (NDIS)

– Win32 Driver Model (WDM)

– Open Data-link Interface (ODI)

• Installing a driver for a NIC is usually easy

NIC Driver Configuration:

Wireless NIC Configuration:

Equipment Perspective

REPEATER

Repeater are used to take the signal that it receive from the computers & other devices on the LAN and regenerate the signal in order for the signal to maintain its integrity while travelling along a longer media run that is normally possible. Repeaters are used within network to extend the length of communication. Repeaters work at the physical layer of OSI model. Repeater do not have any capability of directing network traffic or deciding what particular route

that certain data should take, they are simply devices that sit on the network and boost the data

signal that they receive.

Fig. -Repeater

BRIDGE:

Bridge is an internetworking device used to connect similar network segments. When the bridge

receives the signals it read address of both sender and receiver.

If the sender is a computer in segment A and the receiver is also segment A, it would not pass the

signals to the segments B. It will however pass signals if the sender is in one segment and the

receiver in other segment. Bridge works at the data link layer of O.S.I model .They also use the

software to help get the job done.

Like repeaters they can connect similar network types with different .Bridge extends network

segments by connecting them together to make

Fig.- Bridge

ROUTER:

Routers are devices which connect two or more networks that use similar protocol. A router

consists of hard ware and software. Hard ware can be a computer is specific device. Software

consists of special management program that controls flow of data between networks. Routers

operate at a network layer of O.S.I model.

Routers use logical and physical address to connect two or more logically separate network.

They make this connection by organizing the large network into logical network segment

(sometimes small sub network or sub nets). Each of these sub nets is given a logical address.

Data is grouped into packets or block of data.

Routers are used to segment LAN’s that have become so large to conserve the network

bandwidth. Router allows filtering of data so called smart gateway.

Fig. - Router

GATEWAY:

Gateways are devices which connect two are more networks that use different protocols. A

gateway is used to convert two different environments, such as Frame Relay Network & an X.25

network. For e.g. a gate way can receive email messages in one format in convert them into

another format. Gateway can operate at all seven layer of OSI model.

They are similar in function to routers but they are more powerful and intelligent devices. Since

Gateway perform data conversion so they are lower in speed. Gateway is very expensive device.

Fig.-Gateway

ROUTER TECHNOLOGY MULTIPLEXER:

High-speed signal routing is Procom’s focus within the Silicon Switch™ product family such as Signal Switch IC and Multiplexers. Our patented Charge Pump technology provides the highest signal integrity and achieves the most efficient and clear signal routing for data rates up to 10.1325 Gbps.In systems of increasing complexity, modularization is an essential procedure for allowing timely development.

Modularization however relies on the ability of interconnecting the modules into complete systems. Networks on chip are an emerging paradigm for on-chip communication which simplifies the design of large systems and provides a scalable solution for connecting the on chip processing elements,

memories and peripherals. As the interconnect has an increasing influence on the overall performance of the design, optimizing the networks on chip is an important direction of research. The amount of allocated resources obviously has a direct influence on the achieved performance, however it is also of major importance how efficiently the available resource are used, as the simple increase in path width or router count also has the negative effect of increasing the area. From large-packet-switched networks we have learned that a major limit on efficiency is represented by congestion, while in circuit-switched networks the limitation consists of blocking during allocation and underutilizing the allocated channels.

Fig.- Multiplexer

NETWORK SWITCHES:

A switch is an internetworking device used to manage bandwidth on a large network.

Switches divide network into what is known as a virtual LAN or VLAN. Switches use a

combination of software and hardware to switch packet between computer and other devices

on the N/W.

This software is the switch operating system and because switch offer a high density of

connection ports, they can easily replace hubs on the network this means that each computer

on the N/w can be connected to its own port to the switch, When the comp. are directly

connected to the switch, The switch can supply each of the comp. with a dedicated amount

of bandwidth.

For ex: Say users are on a 100 Mbps Ethernet N/W via a switch. Each user can realize a

bandwidth of 100 Mbps and thus have to compute for a bandwidth the way comp. do on a

N/W via a Hub because each port on the switch has a dedicated 100 Mbps this is why

switches are rapidly replacing hubs. Switches also replaced bridges as the internetworking

devices for conserving network bandwidth and expanding LANs into larger corporate

internetworks.

Fig.- Switches

SUMMARY

NICs supply the interface between a computer and the networking medium

– When sending data, a NIC reformats outgoing data from the parallel form that

arrives through the computer’s bus to the serial form used over most media; to

receive data, the process is reversed

NICs have options that must be set for an adapter to make a working network connection

(usually PnP).NIC’s edge connector must match the PC slot.Many motherboards have integrated

NICs.Network adapters can have a profound effect on overall network performance.When

purchasing a network adapter, consider the following checklist: bus width, bus type, memory

transfer, special features (such as security), bus mastering, and vendor factors (such as

support).When purchasing a wireless NIC, keep in mind the Wi-Fi standard you want to use.

Driver software permits a NIC to communicate with a computer’s operating system

– NIC driver configuration can be auto-configured, or it might require setting some

options

� Check Your Progress 1 1)Role of Network Interface Card? ………………………………………………………………………………… ……..…………………………………………………………………………… … ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ……… 2) What is a NIC ? ………………………………………………………………………………… ……..…………………………………………………………………………… … ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ……… 3)Write Down Main Principal on NIC in Short. ………………………………………………………………………………… ……..…………………………………………………………………………… … ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ……… � Check Your Progress 2

1) A LAN becomes a WAN when you expand the network configuration beyond your own premises and must lease data communication lines from a public carrier.(T)

2) PCI-based modems are less expensive to purchase because the CPU must handle all the processing, making them cheaper to produce.(F)

3) You terminate both workstation drops and backbone wiring using the same device.(T) 4) Brouters operate at both the network layer for routable protocols and at the data link layer

for non-routable protocols.(T)

� Multiple choice/objective type questions

1)Ethernet LAN was developed by: a. IBM b. ARPANET c. DEC, Xerox, and Intel d. University of Minnesota e. CERN laboratory in Geneva

Answer: C

2)The network layer of the Internet model uses the _____________ protocol to route messages though the network. a. TCP b. HTTP c. FTP d. SMTP e. IP

Answer: E

3)TCP/IP: a. is the least commonly used network protocol for LANs because it cannot be combined with Ethernet b. performs packetizing, as well as routing and addressing functions c. is not very efficient and is prone to errors d. is compatible with only one type of data link protocol, SDLC e. refers to Telephone Control Procedures/Inter-exchange Procedures

Answer: B

4)______________ routing is most commonly used when the application data or message can fit into one single packet.

a. Frame-oriented

b. Connection-oriented

c. Connectionless

d. Physical-oriented

e. Byte-oriented

Answer: c

Answer the following questions.

(Questions for short notes) 1)Write one of the following characteristics is true regarding the use of hubs and switches?

Ans. Switches increase the number of collisions domains in the network. Switches that are configured with VLANS will reduce the size of the collision domains by increasing the number of collision domains in a network, but making them smaller than that of one big flat network.

2) When comparing and contrasting the similarities and differences between bridges and switches, which of the following are valid satements?

Ans. Both bridges and switches build the bridge table by listening to incoming frames and examining the source MAC address in the frame. Switches are multiport bridges that allow you to create multiple broadcast domains. Each broadcast domain is like a distinct virtual bridge within a switch.

3) The LAN needs are expanding at the CertKiller corporate office, which is quickly growing. You are instructed to enlarge the area covered by a single LAN segment on the CertKiller network.

Ans. A hub simply repeats the electrical signal and makes no attempt to interpret the electrical signal (layer 1) as a LAN frame (Layer 2). So, a hub actually performs OSI layer 1 functions, repeating an electrical signal, whereas a switch performs OSI layer 2 functions, actually interpreting Ethernet header information, particularly addresses, to make forwarding decisions. Hubs can be used to increase the number of stations that can be supported on a LAN. Because the repeater does not interpret what the bits mean, but does examine and generate electrical signals, a repeater is considered to operrate at Layer 1. Repeaters can be used to physically extend the LAN to greater distances.