Chapter 3 Computer Networking Hardware

What is Networking Hardware? Networking hardware includes all computers, peripherals, network interface cards and other equipment needed to perform data-processing and communications within the network. 14/10/2010 www.eazynotes.com

Computer Networking Hardware Network Interface Card (NIC). Modem Hub Switch Repeater Router Bridge Gateway 14/10/2010 www.eazynotes.com

1) Network Interface Card (NIC) NIC is a device attached to each workstation and server. The NIC provides a physical connection between the networking cable and the computers. NICs come in three basic varieties: 8-bit, 16-bit, 32-bit or more. The larger the number of bits that can be transferred to the NIC, the faster the NIC can transfer data to the network cable. Most NICs are internal with the card fitting into an expansion slot in the computer or built in the motherboard. Wireless devices use WNICs. https://www.youtube.com/watch?v=oIYTqkXBjkU 14/10/2010 www.eazynotes.com

Network Interface Cards (NICs) 14/10/2010 www.eazynotes.com

2) Modems Modems are most frequently used to enable computers to communicate with each other across telephone lines. Stands for Modulation – demodulation. Converts digital signal to analog signal and vice versa. Work as wired / wireless. 14/10/2010 www.eazynotes.com

Modems https://www.youtube.com/watch?v=gqQQCzh_z2Y

3) Hubs A hub is a device that provides a central connection point for cables from computers and other peripherals On this network, all computers can communicate directly with each other. All the nodes connected to a hub share the bandwidth among themselves. Support 8, 12 or 24 ports. Always used in a star topology. https://www.youtube.com/watch?v=Ofjsh_E4HFY 14/10/2010 www.eazynotes.com

Hubs 14/10/2010 www.eazynotes.com

4) Switch A switch is a small hardware device that joins multiple computers together within one Local Area Network (LAN). A switches generally contains more intelligence than a hub. Unlike hubs, switches are capable of inspecting data packets as they are received, determining the source and destination device of each packet, and forwarding them appropriately. Allow several users to send information over a network at the same time without slowing each other down. 14/10/2010 www.eazynotes.com

Switch 14/10/2010 www.eazynotes.com

4) Switch cont.. When the switch receives a data packet, it forwards the packet directly to the recipient device by looking up the MAC address. A switch can utilize the full throughput potential of a networks connection for each device. In other words, say for instance you had a network of 5 PCs and a server all connected with 10 Mbps UTP cable, with a hub the throughput (10 Mbps) would be shared between each device, with a switch each device could utilize the full 10 Mbps connection. https://www.youtube.com/watch?v=Ofjsh_E4HFY 14/10/2010 www.eazynotes.com

5) Repeater Since a signal loses strength as it passes along cable, it is often necessary to boost the signal with a device called a repeater. A repeater is an electronic device that receives a signal, cleans it of unnecessary noise, regenerates it, and retransmits it at a higher power level so that the signal can cover longer distances without degradation.تدهور A good example of the use of repeaters would be in a local area network using a star topology. It is wired / wireless. https://www.youtube.com/watch?v=rYBI1CKuFQ8 14/10/2010 www.eazynotes.com

Repeaters 14/10/2010 www.eazynotes.com

Repeaters Regenerates and propagates all electrical transmissions between 2 or more LAN segments Allows extension of a network beyond physical length limitations Layer 1 of the “OSI model” Higher Layers Physical Repeater Network A Network B 14/10/2010 www.eazynotes.com

6) Router A device to interconnect SIMILAR networks, e.g. similar protocols, similar workstations and similar servers. A router is an electronic device that interconnects two or more computer networks, and interchanges packets of data between them. Each data packet contains address information that a router can use to determine if the source and destination are on the same network, or if the data packet must be transferred from one network to another. If you have a LAN that you want to connect to the Internet, you will need a router to serve as the translator between information on your LAN and the Internet 14/10/2010 www.eazynotes.com

Routers router

Router Connects 2 or more networks and uses network layer addresses (like IP address) to make data forwarding decisions Layer 3 of the “OSI model” A node in Network A A node in Network B Higher Layers Higher Layers Router Network 137.22.144.6 Network 145.65.23.102 Network Network Data Link Data Link Data Link Data Link Physical Physical Physical 1 Physical 2

Uses of Router A router can be used to connect: a Local Area Network (LAN) to another LAN, a Wide Area Network (WAN) to another WAN, a LAN to the Internet. Routers transmit data packets through these networks Choice of paths between LANs https://www.youtube.com/watch?v=IYfGA9p5gZc 14/10/2010 www.eazynotes.com

7) 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 TCP/IP, Ethernet or token ring). The function of a bridge is to connect separate networks together that are of the same type of protocol. A bridge is a device that allows you to segment a large network into two smaller, more efficient networks When a packet is received by the bridge, the bridge determines the destination and source segments. 14/10/2010 www.eazynotes.com

Types of Bridges Bridges come in three basic types: Local bridges: Directly connect local area networks (LANs) Remote bridgesبعيدة : Can be used to create a wide area network (WAN) link between LANs. Remote bridges have been replaced with routers. Wireless bridges: Can be used to join LANs or connect remote stations to LANs. 14/10/2010 www.eazynotes.com

Bridges 14/10/2010 www.eazynotes.com

Bridges LAN A Bridge LAN B Data not destined for other network is prevented from passing over the bridge. Bridge LAN B 14/10/2010 www.eazynotes.com

Bridge Connects 2 or more LAN segments and uses data link layer addresses (e.g.MAC addresses) to make data forwarding decisions Layer 2 of the “OSI model” Node in Network A Node in Network B Higher Layers Physical Higher Layers Physical Bridge Data Link 23-01-88-A8-77-45 Data Link 53-F1-A4-AB-67-4F Data Link Data Link Physical 1 Physical 2 https://www.youtube.com/watch?v=44IPefU5vQo

8) Gateway Gateways are used to interconnect two different networks having different protocols. Networks using different protocols use different addressing formats. A gateway is a network point that acts as an entrance to another network. Gateways are also called protocol converters. 14/10/2010 www.eazynotes.com

Gateway 14/10/2010 www.eazynotes.com

Gateway Connects 2 or more networks that can be of different types and provides protocol conversion so that end devices with dissimilar protocol architectures can interoperate Gateway 137.22.144.6 145.65.23.102 Netware TCP/IP

Gateway Gateway

What is the difference? Router: device to interconnect SIMILAR networks, e.g. similar protocols, workstations and servers. Bridge: device to interconnect two LANs that use the SAME protocol. Gateway: device to interconnect DISSIMILAR protocols and servers, Macintosh,IBM LANs and equipment. 14/10/2010 www.eazynotes.com