Network devices
- 2. NETWORK CONNECTING DEVICES NIC Hub Switch Repeaters Multiplexer MODEM Router Bridges Gateways Firewall
- 3. NIC (NETWORK INTERFACE CARD)
- 4. NIC (NETWORK INTERFACE CARD) • The NIC used to connect the computer to external network. • It would normally have the PCI connector (Edge connector) to connect to one of the PC expansion slots . • An RJ-45 connector to connect to external Ethernet . • Almost all the NICs have LED indicators showing the network connectivity. • NIC are also called Network Adapters and connecting them in a network their installation and configuration is very important. For proper installation of NIC, one needs to pass through three phases: • Setting • Configuration • Interfacing
- 5. INSTALLATION OF NIC Setting: Before connecting NIC it needs settings of particular parameters like IRQ, I/O Address. IRQ is basically interrupt request lines that carry a signal from a device to processor each device in PC must have unique IRQ number. Configuration of NIC: It involves both hardware and software configuration. Configuring these hardware and software configurations the next point comes is interfacing. Interfacing: Once the setting of parameters and configuring of card is done, it is ready for interfacing After proper connection you need to install a standard driver for it.
- 6. HUB Hubs are used to connect two or more computers. However we can connect it without hub but for connecting more than 2 devices we need hub to allow proper data communication within a network HUB ARCHITECTURE A hub looks like a box with ports for LAN nodes to plug in. So most important part of hub is ports used for connecting network nodes
- 7. HUB • Hub is a network connecting device used to connect multiple nodes of a network through a single device. • A hub connects all the nodes of network using Twisted pair cables. • In hub signals received by one port are transmitted to all other ports, and vice versa. • All the nodes connected through hub can listen each other. • The advantage of using hub is low cost and easy integration. • The disadvantage is reduce bandwidth and data security. The reduction in bandwidth comes because all workstations are in same collision domain. If 2 or more workstations try to transmit data at same time can result in collision. As a result available bandwidth of Ethernet network is reduced.
- 8. TYPES OF HUB Passive Hubs: Passive hubs are ones which does not provide any additional feature except for working just as an interface between the topology. These types of hubs do not help in rectifying/enhancing the signals. It simply receives signals on input port and broadcasts it on output ports. Active Hubs: These type of hubs takes participation in data communication within a LAN network. It comes with various features, such as receiving the signal and storing it for sometime before forwarding it, helps transmitting data according to priority highest priority data the lower one. It also rectify/enhance signal before forwarding. Intelligent Hubs: These add some more features than active hubs. It provide all features of passive and active hub. It also provides features, which helps in managing the network resources effectively and efficiently. It helps in improving performance of a network. It helps in finding out where the problem persists. It determines the exact cause of fault. They can device that which packet goes in which output line. It helps in controlling and minimizing the data traffic.
- 9. SWITCH A switch is network device that connects devices on a computer network by using packet switching to receive, and forward data to the destination device. It is similar to Hub but better than it. A switch can join multiple computers within one LAN, and a hub just connects multiple Ethernet devices together as a single segment. A switch on other hand, does not distribute signals without verifying whether it really needs to propagate to given port or not. It verify on base of its internal configuration settings. We can say that a Switch is a Hub with some intelligence.
- 10. BRIDGE A bridge is a type of computer network device that provides interconnection with other networks that use the same protocol. Bridge devices work at the data link layer of the Open System Interconnect (OSI) model, connecting two different networks together and providing communication between them.
- 11. BRIDGE • A bridge functions very similar to a switch. It segments a given network according to the requirements. • Segmentation using bridge enables keeping unnecessary traffic from entering different segments of network. Bridge performs three basic functions: • Examining and learning the address of the nodes. • Frame filtering, reformatting and forwarding. • Routing the frames. Bridge are of two types: 1. Transparent Bridge 2. Source Routing Bridge
- 12. REPEATERS Repeater is a simple hardware device that moves all data packets from one LAN segment to another. During movement it regenerates, and amplifies the electrical signals. A repeater takes incoming signals and repeats it at a higher power so that network speed can be recovered. At same time it makes signal noise free too.
- 13. ROUTER • A router is a device that forwards data packets along networks. It connects multiple networks and uses routing to forward packets. • A router is connected to at least two networks, commonly two LANs or WANs or a LAN and its ISP's network. • A router is a intelligent connecting device that can send packets to the correct LAN segment to deliver it to its destination. • A router finds best route for delivery while data is transmitted
- 14. GATEWAYS • A device which is used to bridge different network architectures is known as “gateway”. • It can handle messages, addresses and protocol for delivery of a packet to its destination between two networks. • Gateways are usually slower than the Bridges and Routers. • The gateways are used to connect two networks that do not communicate with the same network protocol. • Gateways translate these protocols between both networks.
- 15. MODEM • Modem stands for Modulator and Demodulator . • A modem is used to send digital data over phone line. • The sending modem modulates the data into analog signal compatible to phone line. • The receiving modem demodulates the signal back into digital data. • Wireless modems convert digital data into wave signals.
- 16. 1. Internal and External Modems: Internal modems are in form of circuit boards, fitted in expansion slots of motherboard. External modems are enclosed in separate cases and not inside system units. It is connected to computer and telephone line by means of two separate cables. 2. Intelligent and Standard Modems: The standard modems accept instructions entered from keyboard of a microcomputer and respond to commands and transmits information simultaneously. It is done with help of microprocessor chips. 3. Wireless and Short-Haul Modems: Short-Haul modems transfer data by means of cables. Since they don’t need external power source, they are also called modem eliminators. The wireless modems don’t require any kind of cable to transmit the data signals. It transmit data signals through air. TYPES OF MODEM
- 17. MULTIPLEXER • In electronics, a multiplexer (or mux) is a device that selects between several analog or digital input signals and forwards it to a single output line. • A multiplexer is a device that merges several lower speed transmission channels into one high speed channel at one end of the link. • Reverse of multiplexing is called demultiplexing • Multiplexing is done at sender send and demultiplexing is done at receiver end
- 18. FIREWALL TECHNOLOGY Firewall is a system designed to prevent unauthorized access to or from the private network.
- 19. • A firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. • A firewall typically establishes a barrier between a trusted internal network and untrusted external network, such as the Internet. • Firewalls can be implemented on both hardware and software. • Firewalls are commonly used to prevent unauthorized users from accessing private networks connected to internet. • All message entering and leaving through intranet pass through the firewall. • Firewall examines each message and blocks those that do not meet the specified security criteria. FIREWALL
- 20. FIREWALL TECHNIQUES Packet Filters: Looks at each packet entering or leaving the network and accepts and rejects on user defined rules. Application gateway: Applies security mechanisms to specific applications, such as FTP and Telnet servers. Circuit level gateway: Applies security mechanisms when a TCP or UDP connection is established. Once connection is made, packets can flow between the hosts without further checking. Proxy server: Intercepts all messages entering and leaving the network. The proxy server effectively hides the true network addresses.
- 21. FIREWALL TYPES Host Based Firewalls: Host based firewalls are popularly known as personal firewalls are devices or programs intended to protect a single computer. The personal firewalls are generally software based. E.g. Norton Personal Firewalls and Internet Connection Firewall Network Based Firewalls: It normally protects entire network of computer behind firewall. a) Software based firewalls: A firewall that runs on generic OS such as Windows and Linux is known as software firewall. b) Hardware based firewalls: Firewalls that run in proprietary hardware and software environment are known as hardware based firewalls. Enterprise Firewalls: Enterprise firewalls are designed for large geographically distributed networks. They are capable of handling 1000s of users, have faster throughput, and have advanced features. It have ability to manage multiple firewalls centrally.
- 22. FIREWALL ADVANTAGES OF HARDWARE FIREWALLS: • Faster speed • More security DISADVANTAGES OF HARDWARE FIREWALLS: • More costly than software firewalls • Difficult to install ADVANTAGES OF SOFTWARE FIREWALLS: • Cheaper • Ideal for personal use or home use • Easy to configure DISADVANTAGES OF HARDWARE FIREWALLS: • Takes up system resources • Difficult to remove or un-install