TERM PAPER

OF

CSE-316

(Operating Systems)

Topic: Which OS is used to handle computer networks, how it works on LAN?

Submitted by:

MANMEET SINGH Submitted to:

Roll. No- RE2801B40 Lect. Pushpendra Kumar Petriya

Reg. No- 10801620

Course- B Tech.(IT)-M Tech.

ACKNOWLEDGEMENT

I take this opportunity to express my gratitude to our

guide Mr Pushpendra Kumar Petriya who encouraged me

with his critical and constructive suggestions in the Term-

paper.

I am also thankful to my FRIENDS for their invaluable

guidance in this Term-paper. They benefited me with

their experience and skills in the Term-paper.

I again thank all the people who helped me in my

Term-paper for their support and encouragement.

Manmeet Singh

Student sign

Contents:

Operating Systems

Networking

Network Operating Systems

Embedded Operating Systems

Local Area Networks(LAN)

Windows NT/2000 Server

How Network OS works on LAN

Internet Connection Sharing(ICS)

Operation of ICS

Limitations of ICS

Windows XP SP3 Bug

IPv6 Issues

Other Methods

References

INTRODUCTION

Operating Systems

An operating system (OS) is software, consisting of programs and data that runs on computers and manages the computer hardware and provides common services for efficient execution of various application software.

For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between application programs and the computer hardware, although the application code is usually executed directly by the hardware, but will frequently call the OS or be interrupted by it. Operating systems are found on almost any device that contains a computer—from cellular phones and video game consoles to supercomputers and web servers.

Examples of popular modern operating systems for personal computers are Microsoft Windows, Mac OS X, and Linux.

Some operating systems are designed for certain types of equipment, such as Google Android (a variant of Linux), and Symbian - for cell phones Solaris, HP-UX, DG-UX, and other variants of Unix - for server computers

DEC VMS (Virtual Memory System) - for mainframe computers

Other operating systems enjoyed a period of notoriety but are of only historical interest now: Novell Netware was a popular O/S for PCs in the 1990s IBM OS/2 was an early PC O/S that competed with Microsoft Windows for a time but

had limited success

Multics was an especially innovative operating system created in the 1960s for mainframes, that influenced the later development of Unix

Networking

Currently most operating systems support a variety of networking protocols, hardware, and applications for using them. This means that computers running dissimilar operating systems can participate in a common network for sharing resources such as computing, files, printers, and scanners using either wired or wireless connections.

Networks can essentially allow a computer's operating system to access the resources of a remote computer to support the same functions as it could if those resources were connected directly to the local computer. This includes everything from simple communication, to using networked file systems or even sharing another computer's graphics or sound hardware. Some network services allow the resources of a computer to be accessed transparently, such as SSH which allows networked users direct access to a computer's command line interface.

Client/server networking involves a program on a computer somewhere which connects via a network to another computer, called a server. Servers offer (or host) various services to other network computers and users. These services are usually provided through ports or numbered access points beyond the server's network address [disambiguation needed]. Each port number is usually associated with a maximum of one running program, which is responsible for handling requests to that port. A daemon, being a user program, can in turn access the local hardware resources of that computer by passing requests to the operating system kernel.

Many operating systems support one or more vendor-specific or open networking protocols as well, for example, SNA on IBM systems, DEC net on systems from Digital Equipment Corporation, and Microsoft-specific protocols (SMB) on Windows. Specific protocols for specific tasks may also be supported such as NFS for file access. Protocols like ESound, or esd can be easily extended over the network to provide sound from local applications, on a remote system's sound hardware.

Network Operating Systems

A modern O/S contains much built-in software designed to simplify networking of a computer. Typical O/S software includes an implementation of TCP/IP protocol stack and related utility programs like ping and trace route. This includes the necessary device drivers and other software to automatically enable a device's Ethernet interface. Mobile devices also normally provide the programs needed to enable Wi-Fi, Bluetooth, or other wireless connectivity.

The early versions of Microsoft Windows did not provide any computer networking support. Microsoft added basic networking capability into its operating system starting with Windows 95 and Windows for Workgroups. Microsoft also introduced its Internet Connection Sharing (ICS) feature in Windows 98 Second Edition (Win98 SE). Contrast that with UNIX, which was designed from the beginning with networking in view. Nearly any consumer O/S today qualifies as a network operating system due to the popularity of the Internet.

Embedded Operating Systems

A so-called embedded system supports no or limited configuration of its software. Embedded systems like routers, for example, typically include a pre-configured Web server, DHCP server, and some utilities but do not allow the installation of new programs. Examples of embedded operating systems for routers include:

Cisco IOS (Internetwork Operating System) DD-WRT

Juniper Junos

An embedded OS can also be found inside an increasing number of consumer gadgets including phones (iPhone OS), PDAs (Windows CE), and digital media players (iPod Linux).

All About LANs: Local Area Networks

The concept of PC-based network can essentially be traced back to when mainframes and minicomputers were accessed by stand-alone or dumb terminals. However, with the advancements in data storage, security, communication speeds, the need to link microcomputers and networks became crucial.

The local area network or LAN is a group of computers running a specialized communications software and connected via an external data path to network nodes. A LAN can consist of workstations with network interface cards (NICs), hubs, gateways, bridges, switches, routers and servers. The physical media is consisted of Category 5 and fiber optic cabling. Category 5 cables are horizontal cables that are installed from point-to-point between the workstations and the electronics, such as hubs or switches that make up the network.

The cat5 cables terminate to the IDF, intermediate distribution facility, and must not exceed more than 100 meters from the workstations. Fiber optic cables connect all electronic devices throughout the campus to an MDF, main distribution facility. This houses the enterprise category network equipment, which are switches that are capable of switching packages at a rate of 10 or more gigabytes per second and routers with multiple ports that are capable of connecting the enterprise together.

Windows NT/2000 Server

Typically Microsoft, NT and Windows 2000 do just about everything - but nothing outstandingly. NT is the slowest and least reliable network server widely used, but makes an acceptable applications server.

Windows NT has proven a most costly network because low performance requires about 3 times as many servers as with NetWare or OS/2, and a large amount of administrative effort to keep it running. We are told Windows 2000 performs better, is much more reliable and less costly to maintain, but we won't really know if that is true for nearly a year. Microsoft is gearing up to "encourage" people off of NT as quickly as possible.

We recommend you evaluate adopting Windows 2000 very carefully, because the full function of Windows 2000 networking requires a total commitment to Microsoft, Windows 2000 and Active Directory (implemented only on Windows 2000). Attempting to mix Windows 2000 with any other operating systems, even Windows NT and/or Windows95/98, will make most of Win2000's advanced features unavailable.

Windows 2000 fully supports only Windows 2000 clients, but partially supports Windows NT, Windows95/98 and OS/2 clients (OS/2 reluctantly). Windows NT supports Windows95/98, Windows 3.1, Windows NT/2000, DOS and OS/2 clients.

How Network OS works on LAN

A local area network (LAN) supplies networking capability to a group of computers in close proximity to each other such as in an office building, a school, or a home. A LAN is useful for sharing resources like files, printers, games or other applications. A LAN in turn often connects to other LANs, and to the Internet or other WAN. Most local area networks are built with relatively inexpensive hardware such as Ethernet cables, network adapters, and hubs. Wireless LAN and other more advanced LAN hardware options also exist.

Specialized operating system software may be used to configure a local area network. For example, most flavors of Microsoft Windows provide a software package called Internet Connection Sharing (ICS) that supports controlled access to LAN resources.

ICS - Internet Connection Sharing

ICS allows a local network of Windows computers to share a single Internet connection. Microsoft developed ICS as part of Windows 98 Second Edition. The feature has been included as part of all subsequent Windows releases, but it is not available as a separate installable program.

ICS follows a client/server model. To set up ICS, one computer must be chosen as the server. The designated computer must support two network interfaces, one directly connected to the Internet and the other connected to the remainder of the LAN. In a traditional home dial-up network, for example, the server computer is directly connected to the modem.

When configured through Windows, the ICS server behaves as a NAT router, directing messages on behalf of multiple computers. ICS incorporates a DHCP server that allows clients to obtain their local addresses automatically rather than needing to be set manually.

Compared to hardware routers, ICS has the advantage of being included with the operating system so no additional purchase is required. On the other hand, ICS lacks many of the configuration options that hardware routers possess.

Operation of ICS

ICS routes TCP/IP packets from a small LAN to the Internet. ICS maps individual IP addresses of local computers to unused port numbers in the TCP/IP stack. Due to the nature of the NAT, IP addresses on the local computer are not visible on the Internet. All packets leaving or entering the LAN are sent from or to the IP address of the external adapter on the ICS host computer.

On the host computer the shared connection is made available to other computers by enabling ICS in Network Connections, and other computers that will connect to and use the shared connection. Therefore, ICS requires at least two network connections. Normally ICS is used when there are several network interface cards installed on the host. In special cases, only one network interface card is required and other connections may be logical. For example, the host may connect to Internet using a modem/router configured in the bridge mode and share the PPPoE connection with ICS.

Limitations of ICS

However, while ICS makes use of DHCP, there is no way to review (renew?) DHCP leases using ICS. The service is also not customizable in terms of which addresses are used for the internal subnet, and contains no provisions for bandwidth limiting or other features. ICS also was designed to connect only to Windows OS computers: computers on other Operating Systems will require different steps to be able to utilize ICS.

The server will normally have the IP address 192.168.0.1 (the IP Address is changeable) and will provide NAT services to the whole 192.168.0.x subnet, even if the address on the client was set manually, not by the DHCP server. Windows 7 uses the subnet 192.168.137.x by default.

Besides making sure that the firewall settings are correct, for Windows XP hosts with more than one Ethernet interface card and a wireless WAN connection, bridging the Ethernet interface cards may help eliminating some ICS problems. It is found from repeated testing that without bridging, ICS may not work correctly if only one of the several Ethernet cards is selected from the wireless connection's Internet Connection Sharing option drop down box.

Windows XP SP3 Bug: Windows XP Service Pack 3 (SP3) introduces a bug in ICS that requires restarting the ICS Windows service after several events, including disconnecting the network cable from the ICS machine.

In Microsoft support article KB951446, the process of restarting the ICS service is explained, but there is no mention of a plan to fix this bug in the future.

In later Microsoft support article KB951830, more details and a hotfix (Update for Windows XP (KB951830)) are given. This hotfix is not currently being distributed via Windows Update, and so it must be manually installed.

IPv6 Issues: There is a problem with ICS and the IPv6 protocol. It causes systems running ICS to halt on new processes after connecting with a dial-up modem. Any computers using that ICS computer as a host will not be able to access the Internet until the halt ends. Once the system accepts commands again, any new programs started during that time are all opened at once. The issue is caused by running the "Network Setup Wizard", as it installs IPv6 into the computer it was run on. A possible workaround involves uninstalling the IPv6 protocol on the affected computer, which may cause additional problems once IPv6 addresses are depended on to resolve domain names in the next few years.

Other Methods

With the advent of Home and Personal Networking in the mid-to-late 2000's, routers, Wi-Fi Access Points, and other serial communication options have replaced widespread use of Internet Connection Sharing. These alternatives to using Internet Connection Sharing can utilize either dial-up networking (Most focus on the computer with a phone modem to act as a Gateway server to the others sharing the connection) or other connection methods.

REFERENCES:

www.findarticles.com/p/articles/mi_m0SMG/is.../ai_8219632/

www.aaxnet.com/topics/lan.html

www.experts-exchange.com/OS/...Operating_Systems/.../Q_26175725.html

www.howstuffworks.com › ... › Computer Hardware › Networking

www.smartcomputing.com/editorial/article.asp?article...

itknowledgeexchange.techtarget.com › ... › Networking

www.techinterviews.com/network-administrator-interview-questions

www.compnetworking.about.com/.../basicnetworkingconcepts/.../network-operating-systems.htm

www.freewimaxinfo.com/server-types.html

www.articlesbase.com/networks.../server-computer-client-computers-and-computer-network-topology-2911424.html

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