Introduction to Networking Definitions and Terms Chapter Objectives After completing this chapter you will Be able to differentiate between peer to peer and server based networks Be able to identify a network topology Understand the different types of network cabling Be able to explain the differences between various network access methods Understand Ethernet issues Identify OSI model layers Be able to explain when a specific network protocol is used Understand the difference between a MAC address and an IP address Chapter Objectives cont After completing this chapter you will Be able to correctly apply IP addressing concepts Understand the purpose of DHCP WINS and DNS Be able to properly configure a NIC for network connectivity Be able to use common network troubleshooting tools Be able to access a network printer Understand dial up networking concepts and define commonly used network terms Chapter Objectives cont After completing this chapter you will Be able to define and label the basic parts of a wireless network Know that wireless networks operate at layers 1 and 2 of the OSI model Understand the difference between the two main types of wireless networks ad hoc and infrastructure Know the three types of wireless NICs Understand the difference between a BSS and an ESS Be able to explain the purpose of an SSID and channel ID Know the three non overlapping channel IDs used by the 802 11b standard Chapter Objectives cont After completing this chapter you will Understand the purpose of a wireless repeater Be able to explain the basic differences between the antennas and explain the concept of attenuation Know the difference between dBd and dBi Know the purpose and importance of a site survey Understand the difference between 802 11a 802 11b and 802 11g Understand the basics of wireless network security Networking Overview A network is two or more devices capable of communicating and sharing resources between them Two types of networks are LAN and WAN LAN Local Area Network A group of devices sharing resources in a single area such as a room or a building WAN Wide Area Network Two or more LANs communicating often across large distances The most famous WAN is the Internet Types of Local Area Networks Two types of LANs are Server Based and Peer to Peer Network Server Based Network A basic type of LAN wherein users login to a controlling computer called a server and is more secure The server contains information about who can connect to the network and to what shared resources It also provides some of these resources These networks normally consist of 10 or more computers Peer to Peer Network One of two basic types of LANs wherein each computer user acts as a server Each computer stores password and sharing information for its own resources Usually has fewer than 10 computers NOS Network Operating System Special operating system on a server containing utilities for managing users resources and security Types of Local Area Networks Server Based Network Network Figure 1 Types of Local Area Networks Peer to Peer Network Network Figure 2 Network Topologies Network Topology Maps of how the physical or logical paths of network devices connect The three major topologies are star ring and bus Star Topology Most common Ethernet network topology where each device connects to a central hub or switch Hub A device used with the Universal Serial Bus or in a star network topology that allows multiple device connections Switch In star networks a Layer 2 central controlling device A switch looks at each data frame as it comes through each port Ring Topology Network that is physically wired like a star network but logically in a ring passes control from one device to the next in a continuous fashion using a special data packet called a token Used in Token Ring networks Bus Topology Network wherein all devices connect to a single cable If the cable fails the network is down Mesh Topology Network where all devices connect to each other by cabling to provide link redundancy for maximum fault tolerance Most likely in WANs Network Topologies Hub Switch Network Figure 3 Network Topologies Star Topology Network Figure 4 Network Topologies Logical Ring Topology Network Figure 5 Network Topologies Bus Topology Network Figure 6 Network Topologies Network Topologies Network Table 1 Network Cabling Cable is normally used as a medium for transporting network data The most common types are twisted pair and fiber optic although coax is still used in some old networks Twisted Pair Cable Network cable of eight copper wires twisted into four pairs to prevent crosstalk UTP Unshielded Twisted Pair Most common network cable that comes in different categories for different uses Categories 3 voice grade 4 and 5 data It is unshielded and more susceptible to interference STP Shielded Twisted Pair Same as UTP cable but with extra foil to prevent outside noise from interfering with data on the cable Crosstalk Where signals from one wire interfere with the signal on an adjacent wire Plenum cable is treated with Teflon or fire retardant materials to reduce the risk of fire It produces less smoke and is less toxic when burning Network Cabling Fiber Optic Cable An expensive network cabling made of plastic or glass fibers that carry data in the form of light pulses Most often used to connect network devices such as switches together into a network backbone or for connecting networks together in a WAN More secure and not affected by crosstalk or other interference like copper cable Single Mode A type of fiber optic cabling that sends one light beam down the cable Used for longer distance applications Multi Mode A type of fiber optic cabling that allows multiple light signals to be sent along the same cable Used for shorter distances Coaxial Cable Type of copper network cabling used in older Ethernet networks as well as mainframe and minicomputer connections Has a single center wire conductor with an outer braided shield Network Cabling UTP Cable Network Figure 7 Network Cabling Fiber Optic Cable Network Figure 11 Network Cabling Coax Cable with Connector Network Figure 12 Access Methods There are standard rules by which computers on a network must adhere to in order to communicate These rules are known as a common access method CSMA CD Carrier Sense Multiple Access Collision Detect A common access method used by Ethernet Token Passing The common access method used by fiber and Token Ring networks CSMA CA Carrier Sense Multiple