1. Peer-to-Peer vs. Client/Server Network Operating Systems Instructor: Dr. Najla Al-Nabhan 2015 1

2. Peer-to-peer vs. server-based networks  A network is either:  a peer-to-peer network (also called a workgroup) or  a server-based network (also called a client/server network). 2 Client/Server based NWPeer-to-peer based NW

3. Peer-to-peer networks  In a peer-to-peer network, a group of computers is connected together so that users can share resources and information.  In most peer-to-peer networks, it is difficult for users to track where information is located because data is generally stored on multiple computers.  This makes it difficult to back up critical business information, and it often results in small businesses not completing backups.  Often, there are multiple versions of the same file on different computers in the workgroup. 3

4. Peer-to-peer networks  In some peer-to-peer networks, the small business uses one computer that is running a client operating system, such as Microsoft Windows 98 or Windows XP Professional, as the designated "server" for the network.  Although this helps with saving data in a central location, it does not provide a robust solution for many of the needs of a small business, such as collaborating on documents. 4

5. Client/Server Networks  In a server-based network, the server is the central location where users share and access network resources.  This server controls the level of access that users have to shared resources.  Shared resources are in one location, making it easy to back up critical business information.  Each computer that connects to the network is called a client computer. 5

6. Client/Server Networks  In a server-based network, users have one user account and password to log on to the server and to access shared resources.  Server operating systems are designed to handle the load when multiple client computers access server-based resources. 6

7. Client/Server Networks  A Server OS is installed and configured as the central server on a server-based network mainly to provide: 1. the central point for authenticating users, 2. accessing resources, and 3. storing information. 7

8. Peer-to-peer NOS 8  Computers in peer-to-peer networks are usually equipped with a desktop operating system in order to allow them to create and share resources with each other.  All computers are considered equal because they have the same capabilities including : routing and management functions.  Two well-known NOS :  Windows for workgroup/windows 95  Appleshre

9. Peer-to-peer NOS 9  The range of features offered by peer-to-peer NOS is limited when compared to server NOS.  They usually offer file sharing and printing as basic features  For small networks

10. Peer-to-peer NOS: Advantages and disadvantages 10

11. Windows for Workgroups/Windows 95  Windows for Workgroups, introduced in the early 90s  Windows 95, introduced in 1995  They are both considered peer-to-peer networking systems and do not have the capabilities of true internetworking operating systems.  They are, however, inexpensive and more than adequate for small workgroups wanting to share resources, use email, and connect to the Internet. 11

12. Windows for Workgroups/Windows 95  Windows for Workgroups and Windows 95 both offer peer-to-peer network protocols.  The protocols used by these operating systems allow users to share files and devices over LANs.  Both offer NetBEUI (Microsoft’s small network protocol).  They also offer TCP/IP, and IPX/SPX protocols to access the network through either a dialup connection/modem, or directly through a NIC. 12

13. NetBEUI features  Pronounced net-booey, NetBEUI is short for NetBios Extended User Interface.  It is an enhanced version of the NetBIOS protocol used by network operating systems such as:  LAN Manager, LAN Server, Windows for Workgroups, Windows 95 and Windows NT.  Netbeui was originally designed by IBM for their Lan Manager server and later extended by Microsoft and Novell. 13

14. NetBEUI features  NetBEUI protocols, are :  not routable,  more than adequate to meet small LAN needs.  easy to use and do not require in-depth networking knowledge.   NetBEUI software identifies computer devices by name  it is easier to remember that a computer name is Nora than 141.252.20.2 or 141.252.10.1. 14

15. Windows for Workgroups/Windows 95  Each device name in a network must be unique.  NetBEUI software installed on each of the networked computers is all that is necessary to configure devices in order to share resources and create a network.  If a small company does want to connect to the Internet, the necessary software and protocols are available with these operating systems.  Shared resources on Windows for Workgroups/95 networks are accessed by a password that protects the resource and there is only one level of access; either you have access or you don’t have access. 15

16. Windows for Workgroups/Windows 95: Security Issues  Also user-by-user passwords are not part of the protocols unless Windows NT is present.  What this means is that anyone connected to the network who knows the password of the resource has access to that resource.  This can create security issues since there is no way to prevent a user from access once s/he knows the password. 16

17. Windows for Workgroups/Windows 95:Security Issues  As the network grows, it is usually more difficult to keep resource passwords secure.  Since there is no central control, managing these peer-to- peer networks becomes an issue when the network becomes too large. 17

18. Windows for Workgroups/Windows 95:Security Issues  To be continued next lecture… 18