Institute of Technology Sligo - Dept of Computing LAN Maps & Symbols Topologies & Devices Paul Flynn

Institute of Technology Sligo - Dept of Computing By the end of this Chapter, you will be able to name and describe all the symbols in this diagram.

Institute of Technology Sligo - Dept of Computing Physical & Logical Topologies  Physical Topologies define the actual layout of the wire (media).  For example, this classroom’s wiring is laid out in an extended star  Logical Topologies define how the media is accessed by the hosts.  For example, in this classroom hosts access the media on a first come, first served basis

Institute of Technology Sligo - Dept of Computing Physical Topologies Bus Ring Star Extended Star Hierarchical Mesh

Institute of Technology Sligo - Dept of Computing Bus Topology  Single backbone  All hosts directly connected to backbone  Each end of the bus must be properly terminated

Institute of Technology Sligo - Dept of Computing Ring Topology  No backbone  A host is directly connected to each of its neighbors  Used for token passing logical topologies

Institute of Technology Sligo - Dept of Computing Star Topology  All devices connected to a central point  Center of star is usually a hub or a switch  Used for Ethernet technologies

Institute of Technology Sligo - Dept of Computing Extended Star Topology  Connects individual star topologies together.  At the center of the star is a hub or a switch.  Extends the length and size of the network.  This is the topology we are using in our lab!

Institute of Technology Sligo - Dept of Computing Hierarchical Topology  Like the extended star except a computer controls traffic—not a hub or a switch. Server

Institute of Technology Sligo - Dept of Computing Mesh Topology  Each host has its own connection to every other host  Used in situations where communication must not be interrupted.

Institute of Technology Sligo - Dept of Computing Logical Topologies  Broadcast Topology  Each host on the LAN sends its data (or broadcasts its data) to every other host.  Access to media is based of “first-come, first-serve.” (Ethernet works this way)  Token Passing Topology  Access to media is controlled by an electronic token.  Possession of the token gives the host the right to pass data to its destination.

Institute of Technology Sligo - Dept of Computing LAN Media Symbols Token Ring FDDI Ring Ethernet Line Serial Line

Institute of Technology Sligo - Dept of Computing LAN Device Symbols—Layer 1 Transceiver Hub Repeater

Institute of Technology Sligo - Dept of Computing LAYER 1—Repeater  Cleans up (regenerates) and repeats the signal.  Used when a network’s cabling extends beyond its capability.

Institute of Technology Sligo - Dept of Computing LAYER 1—Transceiver  Transmitter and Receiver of electronic signals—specialized repeater.  Connects different media technologies  Also called a MAU (Media Attachment Unit) Fiber Cat 5 UTP

Institute of Technology Sligo - Dept of Computing LAYER 1—Hub  Simply a multi-port repeater.  Used to connect multiple devices to the same network drop. The Cloud

Institute of Technology Sligo - Dept of Computing LAN Device Symbols—Layer 2 Bridge Switch

Institute of Technology Sligo - Dept of Computing LAYER 2—Bridge  Connects two LAN segments.  Keeps traffic local by filtering traffic based on MAC Addresses.

Institute of Technology Sligo - Dept of Computing LAYER 2—Switch  Connects multiple LAN segments.  Can be called a multi-port bridge.  Provides full bandwidth out each port. The Cloud

Institute of Technology Sligo - Dept of Computing LAN Device Symbols—Layer 3 Router

Institute of Technology Sligo - Dept of Computing LAYER 3—Router  Can be used to connect different Layer 2 devices and different topologies.  Makes decisions based on network addresses (IP Addresses).  What are the routers two main functions? The Cloud

Institute of Technology Sligo - Dept of Computing Router’s Two Main Functions  Path Determination  Packet Switching

Institute of Technology Sligo - Dept of Computing Router’s Two Main Functions Path Determination is the process of evaluating a packet’s destination IP address so that the router can decide which port to send out the packet.

Institute of Technology Sligo - Dept of Computing Router’s Two Main Functions In Packet Switching, the router re- encapsulates the packet in the protocol needed for the specified port and then switches the packet out that port.

Institute of Technology Sligo - Dept of Computing The Cloud  The cloud is a collection of devices that operate at all levels (7-1) of the OSI model.  The cloud is used to represent a large group of details that are not pertinent to a situation or description, at a given time.  The cloud helps remind us that our discussions are about various parts of a larger interconnected network—The Internet! The Cloud

Institute of Technology Sligo - Dept of Computing Engineering Journal Assignment Draw freehand the Teaching Topology found in the second graphic on Screen (shown below). As you draw it, test your knowledge about the various topologies and devices.