Fall 2013 Networking Presentation  

    Networks Networks are a collection of computers and other hardware connected together. They provide communication between a minimum of two devices. Networks come in various topologies. Each topology has advantages and disadvantages when compared to each other.

Ring Topology All devices are connected to each in a virtual ring. Uses a token to communicate between the devices. Only the computer with the token can transmit to the other devices. The system uses a Multi-Station Access Unit (MAU) hub. The MAU sends the signal to each device in the ring, until the computer with the token receives the original message back.

Ring Network  

Star Topology Most popular topology.              Offers greater flexibility over other topologies. Each device has a dedicated connection to the hub or switch.  The entire network can be affected if the central hub or switch fails. 

    Star Network

Bus Topology Also known as Daisy Chain.             Signals from each device travel on a bi-directional bus. The Bus has two cable ends that must be terminated. A faulty cable, terminated end or bad connection will affect the entire network. A split in the network will cause signals to become scrambled across the whole network.  

   Bus Topology CSMA / CD.              Carrier Sensing - Multiple Access / Collision Detection. Is software that senses when the line is busy.  

   Bus Network  

It is only practical for small sized networks.    Mesh Topology Each computer has a dedicated connection to every other computer on the network.              It is only practical for small sized networks. It is more tolerant to device and cable failures than other topologies.  

   Mesh Network  

   Hybrid Networks Are designed to take advantage of the strengths of each combined network.              Help minimize the weaknesses of the combined networks. It can handle device and cable failures better than the individual networks on their own. Star/Bus and Star/Ring are two examples of Hybrid Networks. 

   TCP / IP A group of networking protocols used to connect computers on the Internet. TCP provides transport functions while IP provides the addressing and routing mechanism. TCP/IP includes FTP, SMTP (Simple Mail Transfer Protocol),Telnet and UDP (User Datagram Protocol)  

DHCP Dynamic Host Configuration Protocol (DHCP). DHCP is used to dynamically assign IP addresses on the network. DHCP is used to conserve IP addresses. When a device connects to the network, DHCP will "lease" an IP address to it. When that device is not using the network, DHCP can use the same IP address for another device.  

Network Communications Half Duplex is where a device is only capable of one way communications. Send or Receive. Full Duplex is where the device can both send and receive signals at the same time.

  Network Wiring  

    Network Cables  

  Twisted Pair Cable Twisted Pair Cables are currently the most commonly used network cables. Frequently used in Star Topology Networks. Available in shielded and non-shielded styles. It has eight individual wires twisted into four pairs, enclosed inside a single sheath.  The pairs are twisted at different rates to reduce interference.  

  RJ45  

  Twisted Pair Cable The Telecommunications Industry Association (TIA) and Electronics Industry Association (EIA) developed the  TIA/EIA-568 standard. CAT-5 10BaseT or 100BaseT can be wired two different ways and maintain conformance with T568A or T568B standards. 10Base and 100Base ethernet networks generally use only two of the four twisted wire pairs.  

  Twisted Pair Cable Category 5 (CAT-5) cable is the most common standard used today. CAT-5 is suitable for networks running at 100 Mbps or slower. CAT 5e cable is designed at a 100 MHz frequency on cable segments of up to 100 meters.  Depending on performance standards, CAT-5 can be used in 1000BaseT networks.  

  Twisted Pair Cable CAT-6 is suitable for networks running at 1000 Mbps up to 100 meter segments. CAT-6 cable can support 10 Gbps on cable segments of up to 55 meters.   CAT-6a will support 10 Gbps networks up to 100 meter segments.  

   Twisted Pair Cable  

Shielded Twisted Pair Cable Shielded Twisted Pair Cables come in two types. Type 1A and Type 6A. It is used where additional shielding is needed against electromagnetic interference. It only has two pairs of twisted wires with the addition of foil or mesh shielding. Frequently used in Ring Topology Networks.  

   RJ45 & RJ11  

RJ45 vs RJ11 RJ stands for Registered Jack. RJ45 is used with ethernet cables in computer networking.  RJ11 is used in connecting telephone units. RJ45 contains more wires,(8) than RJ11 (4). RJ45 is physically bigger than RJ11 to accommodate the extra wires.  

   Coaxial Cable  

  Coaxial Cable Two types of Coaxial cable are used for computer networking. RG-8 (Thick ethernet) Is a 10Base5 format that has a maximum cable length of 500 meters. RG-58 (Thin ethernet) Is a 10Base2 format that has a maximum cable length of 200 meters. Both are limited to a speed of 10 Mbps & use base-band transmissions. Frequently used in Bus Topology Networks.  

   Coaxial Cable  

  Fiber Optic  

  Fiber-optic Cable Fiber-optic cable carries light instead of electrical signals. Normally has the light converted to electronic impulses when connecting to the NIC . It is resistant to any electromagnetic interference. It can span distances of 120km without signal degradation.  It offers a more secure form of transmission.  

Fiber Optic Connections  

  Fiber-optic Cable There are two types of fiber-optic cable, single-mode and multimode. Single-mode uses a laser as a light source and has a smaller core. Multimode uses a LED as a light source and can process multiple wavelength signals. Two common connectors used in fiber-optics include the Straight tip (ST) and the Subscriber connector (SC).  

   Plenum Rated Cable  

  Plenum Rated Cable The plenum is an open space found above a building’s dropped ceilings. Plenum spaces often house telephone and network communication cables. Plenum rated cables must comply with the NEC specifications for flammability and smoke density. Plenum rated cables need to be coated in flame-retardant, low smoke materials such as polyvinyl chloride (PVC). 

  Network Hardware  

Repeaters are simple devices that act as a signal amplifiers. Repeaters can remove noise from the incoming signal, but cannot correct corrupted messages. Repeaters can be used as media adapters, such as converting signals from a fiber-optic line over to a twisted pair line. The use of repeaters should be avoided on network segments with high volumes of traffic.   

  Routers  

  Routers Routers are used to transfer information between separate networks. Routers can analyze and in some cases correct corrupt packets of data. They use a routing table to direct information to the correct network address. Routers must be directly connected to each network and have an IP address in each network.   

  Network Hub  

  Network Hubs Hubs are simple devices used to connect multiple computers together. They are available in active and passive configurations. Hubs lack the ability to route incoming messages and broadcast on all output lines. Hubs are used in Token Ring networks as a Multi-station Access Unit (MAU).  Hubs must operate in half-duplex mode.  

  Network Switch  

  Network Switches Network switches act as a central connection point for network devices. Frequently used in Star Topology Networks. Switches directly send received messages to the destination address. This allows the switch to operate in full-duplex mode.   Switches help reduce network collisions and as a result increase network bandwidth.  

  Network Switch  

  Network Switches Switches improve network security by limiting communication to specific ports. Switches can read and analyze the data they are receiving. This makes them useful for troubleshooting network problems. Switches can be configured to either manually or auto negotiate half or full duplex modes with other network devices.