© ExplorNet’s Centers for Quality Teaching and Learning 1 Select appropriate hardware for building networks. Objective Course Weight 2%

© ExplorNet’s Centers for Quality Teaching and Learning 2 Essential Components Computer networks consist of three essential components:  End Devices – User connection to the network.  Intermediary Devices – The devices that handle the information exchange in between the end devices.  Media – The various connecting wires and signals that allow the devices to communicate. The focus of this section will be on the intermediary devices and media components.

© ExplorNet’s Centers for Quality Teaching and Learning 3 End Devices These are the user’s interface to the network. They include, but are not limited to:  Desktops  Laptops  Tablets  Mobile Phones  IP Phones  Printers  Servers  Smart Devices (TVs, Refrigerators, etc.)

© ExplorNet’s Centers for Quality Teaching and Learning 4 End Devices on the Network  Connecting desktops, laptops, and servers to a network depends on the Operating System (OS) that the device is running.  All of the other end devices can be connected to a network by following manufacturer specific instructions that can usually be found on the manufacturer’s support web site.

© ExplorNet’s Centers for Quality Teaching and Learning 5 Intermediary Devices These handle the flow of information to and from end devices. They include, but are not limited to:  Switches (Layer 2 and Layer 3)  Routers  Firewalls  Wireless Access Points (WAPs)  Hubs (deprecated due to the advent of switches)

© ExplorNet’s Centers for Quality Teaching and Learning 6 Intermediary Devices This section focuses on the first two devices in this list  Switches (Layer 2 and Layer 3)  Routers  Firewalls  Wireless Access Points (WAPs)  Hubs (deprecated due to the advent of switches) Firewalls and WAPs are critical components in the modern network, and are covered in Security unit 207.

© ExplorNet’s Centers for Quality Teaching and Learning 7 Switches  They are used to connect multiple computers in a LAN setting.  Replaced hubs.  OSI model: Layer 2  Delivers data based on MAC addresses.  Keep a table of connected MAC addresses to support quick communication.

© ExplorNet’s Centers for Quality Teaching and Learning 8 Switches  Switches have a wide variety of features.  Unmanaged vs. Managed (VLANs)  Fast Ethernet vs. Gigabit Ethernet  Copper Uplink vs. Fiber Uplink  Layer 2 vs. Layer 3  Non-Power over Ethernet (PoE) vs. PoE  In the above list, the second option is generally more expensive, more advanced, and preferred for a more robust network.  Come in a variety of port configurations.  Usually multiples of 2.  5, 8, 16, 24, and 48 are common.

© ExplorNet’s Centers for Quality Teaching and Learning 9 Routers  Used to interconnect networks.  OSI model: Layer 3  Delivers data based on IP addresses.  Gateway routers connect LAN to WAN.  Bridge routers connect LAN segments together.

© ExplorNet’s Centers for Quality Teaching and Learning 10 Routers  Routers are usually thought of as a stand alone hardware device, but Windows Servers can operate as software-based routers as well.  Like switches and their MAC address tables, routers maintain tables called route tables that keep track of other nearby routers.

© ExplorNet’s Centers for Quality Teaching and Learning 11 Routers Static Routes versus Dynamic Routes  When route tables are maintained manually by an administrator they are referred to as static route tables.  These are rarely used today due to the complexity of modern IP networks.  Most route tables today are maintained by different routing protocols in which routers automatically figure out how to handle traffic.  This is called dynamic routing.

© ExplorNet’s Centers for Quality Teaching and Learning 12 Routers Dynamic Routing Protocols  RIP – Router Information Protocol  Distance-vector based protocol that uses an algorithm to determine how to send traffic.  OSPF – Open Shortest Path First  Link-state protocol that monitors if a link is on/off to determine the best way to route traffic.  IGRP – Interior Gateway Routing Protocol  Cisco-owned and developed protocol that is an improved version of RIP.  BGP – Border Gateway Protocol  Exterior gateway protocol used to determine best routes across the Internet.

© ExplorNet’s Centers for Quality Teaching and Learning 13 Media These are the channels that data travels through. They include, but are not limited to:  Fiber Optic Cable  Twisted Pair Cable  Coaxial Cable  Wireless Channels Each of these media types are common in today’s networks. Coaxial is less common inside the LAN.

© ExplorNet’s Centers for Quality Teaching and Learning 14 Fiber Optic Cable  Fiber optic cable should be used when the highest bandwidth is desired, and money is not an issue.  Multimode fiber is generally used inside the LAN.  The longer a multimode run is stretched the slower the bandwidth.  Single mode fiber is used for long-haul WAN connectivity.  Single mode fiber is quite incredible. It can maintain throughput of ~40Gbps at distances exceeding 100km.  Fibers are usually run in pairs because a single fiber is unidirectional.  Two fibers are required for duplex transferring.

© ExplorNet’s Centers for Quality Teaching and Learning 15 Twisted Pair Cable  Twisted pair is the most commonly used network media because of its transmission speeds and value.  It is less expensive than coaxial and fiber.  It can transmit data at gigabit speeds.  It comes in shielded and unshielded varieties in case there is an area where the network may experience interference.  It also comes with plenum and non-plenum ratings in case the wire is run through plenum space.

© ExplorNet’s Centers for Quality Teaching and Learning 16 Coaxial Cable  Coaxial cable is a very rugged cable type that is designed to resist interference.  This cable type is commonly used by cable TV and satellite TV providers.  It is recommended for installations where the cable may experience a wide variety of environmental conditions.

© ExplorNet’s Centers for Quality Teaching and Learning 17 Wireless Channels  Radio frequency media is becoming more popular each year.  The increase in popularity of this media type is driven by the rise in the use of mobile end devices.  It is great to use when a device needs to be free and mobile for purposes such as presentation.  The largest drawback of wireless media is the possibility of Radio Frequency Interference (RFI).  Another obstacle to the use of wireless media are dense, solid walls which prevent the signal from broadcasting.

© ExplorNet’s Centers for Quality Teaching and Learning 18 Putting It All Together  Gateway Routers connect to the Internet.  Bridge routers connect one network to another network.  Switches and WAPs connect end devices to the network.  Different media is used to connect the end and intermediary devices together based on the requirements of the network.

© ExplorNet’s Centers for Quality Teaching and Learning 19 Putting It All Together