Network Concepts Devices Introduction into Network Devices HNC COMPUTING - Network Concepts

HNC COMPUTING - Network Concepts Aims Gain a knowledge about network devices. Discuss what network devices are required to create a basic network Draw a bespoke network drawing using Visio HNC COMPUTING - Network Concepts

HNC COMPUTING - Network Concepts Network Devices In order to setup a network a variety of devices are required. The network devices differ according to what network you intend to setup. A network segment is a portion of a computer network where every device communicates using the same physical layer. HNC COMPUTING - Network Concepts

HNC COMPUTING - Network Concepts Basic Network A simple network can be created between two computers (peer to peer). In order to create this connection each computer must have an NIC network interface card. A Network card, Network Adapter, LAN Adapter or NIC (network interface card) is a piece of computer hardware designed to allow computers to communicate over a computer network. HNC COMPUTING - Network Concepts 4

Basic Network

Basic Network An NIC provides physical access to a networking medium and provides a low-level addressing system through the use of MAC (Media Access Control) addresses. It allows users to connect to each other either by using cables or wirelessly.

HNC COMPUTING - Network Concepts Other Networks HNC COMPUTING - Network Concepts 7

HNC COMPUTING - Network Concepts Other Network Devices There are a variety of different network devices that are available, each of which has a specific role within the network. Some of which are listed below: Switch Hub Router Bridge Gateway HNC COMPUTING - Network Concepts 8

HNC COMPUTING - Network Concepts Other Network Devices Switches A network switch is a device that connects network segments. A switch is intelligent, it can recognise what cable has been inserted into it and adapt to allow the network to communicate. An Ethernet switch automatically divides the network into multiple segments, acts as a high-speed, selective bridge between the segments, and supports simultaneous connections of multiple pairs of computers which don't compete with other pairs of computers for network bandwidth.  It accomplishes this by maintaining a table of each destination address and its port.  When the switch receives a packet, it reads the destination address from the header information in the packet, establishes a temporary connection between the source and destination ports, sends the packet on its way, and then terminates the connection. HNC COMPUTING - Network Concepts 9

HNC COMPUTING - Network Concepts Other Network Devices Hubs A network hub is a device for connecting multiple devices together, making them act as a single network segment. When a hub receives a packet (chunk) of data (a frame in Ethernet lingo) at one of its ports from a PC on the network, it transmits (repeats) the packet to all of its ports and, thus, to all of the other PCs on the network.  If two or more PCs on the network try to send packets at the same time a collision is said to occur.  When that happens all of the PCs have to go though a routine to resolve the conflict.  The process is prescribed in the Ethernet Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol.  Each Ethernet Adapter has both a receiver and a transmitter.  If the adapters didn't have to listen with their receivers for collisions they would be able to send data at the same time they are receiving it (full duplex).   Because they have to operate at half duplex (data flows one way at a time) and a hub retransmits data from one PC to all of the PCs, the maximum bandwidth is 100 Mhz and that bandwidth is shared by all of the PC's connected to the hub. The result is when a person using a computer on a hub downloads a large file or group of files from another computer the network becomes congested.  In a 10 Mhz 10Base-T network the affect is to slow the network to nearly a crawl.  The affect on a small, 100 Mbps (million bits per scond), 5-port network is not as significant. HNC COMPUTING - Network Concepts 10

HNC COMPUTING - Network Concepts Other Network Devices What is the difference between a Hub and a Switch? A hub receives a packet at one of its ports from a PC on the network, it transmits the packet to all of its ports (broadcast) thus, to all of the other PCs on the network. A hub does not use any intelligence to determine the destination of a packet, whereas a switch does. HNC COMPUTING - Network Concepts 11

HNC COMPUTING - Network Concepts Tasks What problems could occur as a result of using a hub? HNC COMPUTING - Network Concepts 12

HNC COMPUTING - Network Concepts Other Network Devices Router This is a device that forwards and routes data packets along networks. A router is often included as part of a network switch. A router is located where one network meets another. It prevents the traffic on one from unnecessarily spilling over to the other. This process is known as routing. In performing these two jobs, a router joins the two networks, passing information from one to the other and, in some cases, performing translations of various protocols between the two networks. It also protects the networks from one another, preventing the traffic on one from unnecessarily spilling over to the other. This process is known as routing HNC COMPUTING - Network Concepts 13

HNC COMPUTING - Network Concepts Other Network Devices Bridge A bridge is a device that connects two networks so that they act as if they’re one network. A key feature of a bridge is to enable a large network to be partition into two smaller, more efficient networks. Bridges work best in networks that are highly segregated. A bridge directs frames according to hardware assigned MAC addresses while a router makes its decisions according to assigned IP Addresses. HNC COMPUTING - Network Concepts 14

HNC COMPUTING - Network Concepts Other Network Devices Gateway The main job of a gateway is to convert protocols among communications networks. A gateway can accept a packet formatted for one protocol (e.g. AppleTalk) and convert it to a packet formatted for another protocol (e.g. TCP/IP) before forwarding it. A gateway can be implemented in hardware, software or both, but they are usually implemented by software installed within a router. HNC COMPUTING - Network Concepts 15

HNC COMPUTING - Network Concepts Tasks Using the internet look into the various other available network devices/terms, including multiplexers, ADSL, Analogue and digital frequencies. Asymmetric Digital Subscriber Line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide. It does this by utilizing frequencies that are not used by a voice telephone call. A splitter - or microfilter - allows a single telephone connection to be used for both ADSL service and voice calls at the same time. (BT) DSL or xDSL, is a family of technologies that provide digital data transmission over the wires of a local telephone network. DSL originally stood for digital subscriber loop, although in recent years, the term digital subscriber line has been widely adopted as a more marketing-friendly term for ADSL, which is the most popular version of consumer-ready DSL. DSL uses high frequency, while regular telephone uses low frequency on the same telephone line. (NTL) HNC COMPUTING - Network Concepts

HNC COMPUTING - Network Concepts Conclusion Gained knowledge about network devices Discuss what network devices are required to setup a network HNC COMPUTING - Network Concepts