1. Understanding the Basic of Computer Network: Networking Hardware and Network

2. Networking Hardware File Servers Workstations Network Interface Card Repeaters Hub Switch Bridges Router

3. Introduction Networking hardware includes all computers, peripherals, interface cards and other equipment needed to perform data‐ processing and communica;ons within the network.

4. File/Network Server One or more network servers is a part of nearly every local area network. These are very fast computers with a large amount of RAM and storage space, along with a one or more fast network interface card(s). The network opera;ng system provides tools to share server resources and informa;on with network users.

5. File/Network Server (cont.) A sophis;cated permissions‐handling system is included, so that access to sensitive information can be carefully tailored to the needs of the users. For small networks, a singe network server may provide access control, file sharing, printer sharing, email, database, and other services.

6. File/Network Server

7. Workstations Computers that humans use are broadly categorized as workstations. A typical workstation is a computer that is configured with a network interface card, networking soSware, and the appropriate cables. Worksta;ons do not necessarily need large storage hard drives, because files can be saved on the file server. Almost any computer can serve as a network workstation.

8. Network Interface Cards The network interface card (NIC) provides the physical connec;on between the network and the computer worksta;on. Network interface cards are a major factor in determining the speed and performance of a network. It is a good idea to use the fastest network card available for the type of worksta;on you are using. The most common network interface connec;ons are Ethernet cards and wireless adapters.

9. Network Interface Cards (cont.) Ethernet card can be used with coaxial, twisted pair, or fiber op;cs cable. Wireless adapters are found in most portable devices, such as laptops, smart phones, and tablet devices.

10. Network Interface Cards (cont.)

11. Repeater Since a signal loses strength as it passes along a cable, it is oSen necessary to boost the signal with a device called a repeater. The repeater electrically amplifies the signal it receives and rebroadcasts it. They are used when the total length of your network cable exceeds the standards set for the type of cable being used.

12. Repeater (cont.) Func;ons at the Physical Layer of the OSI model A mul;‐port repeater is known as a Hub Connects segments of the same network, even if they use different media Repeater

13. Hub Allows the mul;ple connec;on of devices In reality a Hub is a Repeater with mul;ple ports Func;ons in a similar manner to a Repeater Works at the Physical Layer of the OSI model Hubs do not manage any of the traffic that comes through them. Any packet entering a port is broadcast out or "repeated" on every other port, except for the port of entry.

14. Hub (cont.) hub

15. Switch An switch is a device that provides a central connec;on point for cables from worksta;ons, servers, and peripherals. Modern switches build a port map of all IP address which respond on each port, and only broadcasts on all ports when it doesn't have a packet's target IP address already in its port map. An switch operates atLayer 2 (the data link layer) of the OSI model. Most large networks use switches rather than hubs to connect computers within the same subnet.

16. Switch (cont.)

17. Bridge A bridge is a device that connects a local area network (LAN) to another local area network that uses the same protocol (for example, Ethernet or Token Ring). It looks at the des;na;on of the packet before sending. If the des;na;on address is not on the other side of the bridge it will not transmit the data. A bridge only has one incoming and one outgoing port. Bridges are typically used to separate parts of a network that do not need to communicate regularly, but s;ll need to be connected.

18. Bridge (cont.) A B C D E F G H Bridge Segment A Segment B A Transmits to C, bridge will not pass it to Segment B G Transmits to B, bridge will pass it to Segment A

19. Router A router is similar in a switch in that it forwards packets based on address. But, instead of the MAC address that a switch uses, a router can use the IP address. This allows the network to go across different protocols. A router is connected to two or more data lines from different networks. An Router operates atLayer 3 (the network layer) of the OSI model.

20. Router (cont.) Work in LAN, MAN and WAN environments Can interconnect different networks – Ethernet with Token Ring Allows access to resources by selec;ng the best path Two primary func;ons – to determine the ‘best path’ and to share details of routes with other routers

21. Router (cont.) Two primary func;ons – to determine the ‘best path’ and to share details of routes with other routers Rou;ng Table – a database which keeps track of the routes to networks and the associated costs

22. Router (cont.) Sta;c Rou;ng – routes are manually configured by a network administrator Dynamic Rou;ng – adjust automa;cally to changes in network topology, and informa;on it receives from other routers Rou;ng Protocol – uses a special algorithm to route data across a network

23. Firewall A firewall is a networking device that is installed at the entrance to a LAN when connec;ng a networks together, par;cularly when connec;ng a private network to a public network, such as the internet. Firewalls are either hardware or soSware, depending on their intended use.

24. Network Opera;ng System Unlike opera;ng systems, such as Windows, that are designed for single users to control one computer, network opera;ng systems (NOS) coordinate the ac;vi;es of mul;ple computers across a network. The network opera;ng system acts as a director to keep the network running smoothly. The two major types of network opera;ng systems are: – Peer to Peer – Client/Server

25. Peer‐to‐Peer Peer‐to‐peer network opera;ng systems allow users to share resources and files located on their computers and to access shared resources found on other computers. However, they do not have a file server or a centralized management source In a peer‐to‐peer network, all computers are considered equal; they all have the same abili;es to use the resources available on the network.

26. Peer‐to‐Peer (cont.) Peer‐to‐peer networks are designed primarily for small to medium local area networks. Nearly all modern desktop opera;ng systems, such as Macintosh OSX, Linux, and Windows, can func;on as peer‐to‐peer network opera;ng systems.

27. Peer‐to‐Peer (cont.) Advantages of a peer‐to‐peer network: – Less ini;al expense ‐ No need for a server. – Setup ‐ An opera;ng system (such as Windows XP) already in place may only need to be reconfigured for peer‐to‐peer opera;ons. Disadvantages of a peer‐to‐peer network: – Decentralized ‐ No central loca;on for files and applica;ons. – Security ‐ Does not provide the security available on a client/server network.

28. Client/Server Client/server network opera;ng systems allow the network to centralize func;ons and applica;ons in one or more file servers The file servers become the heart of the system, providing access to resources and providing security. Individual worksta;ons (clients) have access to the resources available on the file servers. UNIX/Linux and the MicrosoS family of Windows Servers are examples of client/server network opera;ng systems.

29. Client/Server (cont.)

30. Advantages of a client/server network: – Centralized ‐ Resources and data security are controlled through the server. – Scalability ‐ Any or all elements can be replaced individually as needs increase. – Flexibility ‐ New technology can be easily integrated into system. – Interoperability ‐ All components (client/network/ server) work together. – Accessibility ‐ Server can be accessed remotely and across mul;ple plaeorms

31. Client/Server (cont.) Disadvantages of a client/server network: – Expense ‐ Requires ini;al investment in dedicated server. – Maintenance ‐ Large networks will require a staff to ensure efficient opera;on. – Dependence ‐ When server goes down, opera;ons will cease across the network.

32. Network Opera;ng System SoSware some of the more popular peer‐to‐peer and client/server network opera;ng systems: – Macintosh OS X – MicrosoS Windows Server – UNIX/Linux