1. Local Area Networks Andres, Wen-Yuan Liao Department of Computer Science and Engineering De Lin Institute of Technology andres@dlit.edu.tw http://www.cse.dlit.edu.tw/~andres

3. Overview Local area network (LAN) devices High-speed, low-error data networks that cover a relatively small geographic area Connect workstations, peripherals, terminals, and other devices

4. Basic LAN Devices The topology LAN devices in a topology NICs,Media Repeaters, Hubs, Bridges, Switches Routers Clouds, Network segments

5. Topology Defines the structure of the network Physical topology The actual layout of the wire (media) Logical topology Defines how the media is accessed by the hosts.

7. Physical topology Bus Uses a single backbone segment All the hosts connect to it directly Ring Connects one host to the next and the last host to the first Star Connects all cables to a central point

8. Physical topology Extended star Links individual stars together by linking the hubs/switches. hierarchical Similar to an extended star The system is linked to a computer The computer controls the traffic on the topology Mesh Each host is connected to all other hosts Internet

9. Logical topologies Broadcast Each host sends its data to all other hosts on the network medium (no order) Token-passing Controls network access by passing an electronic token sequentially to each host When a host receives the token, that means that that host can send data on the network

11. LAN devices in a topology Devices that connect directly to a network segment are referred to as hosts Operate at all 7 layers

13. NICs An NIC card is a printed circuit board Layer 2 device Media Access Control (MAC) address AUI (Attachment Unit Interface) RJ-45 BNC

15. AUI

17. Media Carry a flow of information Be considered Layer 1 components  Cable length  Cost  Ease of installation

19. Repeaters One of the disadvantages of the type of cable that we primarily use (CAT5 UTP) is cable length Repeaters: strengthen their signals over long distances The purpose of a repeater is regenerate and retime network signals

20. Repeaters 5-4-3 Rule: you can connect five network segments end-to- end using four repeaters but only three segments can have hosts (computers) on them

23. Hubs Multi-port repeater Create a central connection point for the wiring media Increase the reliability of the network

25. Classifications I Active They take energy from a power supply to regenerate network signals Passive They merely split the signal for multiple users

26. Classifications II Intelligent hubs Have console ports, which means they can be programmed to manage network traffic Dumb hubs Take an incoming networking signal and repeat it to every port without the ability to do any management

27. Repeaters Token-ring network : Media Access Unit (MAU) FDDIs: the MAU is called a concentrator.

28. Bridges Layer 2 device To filter traffic on a LAN To keep local traffic local Allow connectivity to other segments Every networking device has a unique MAC address on the NIC

30. Switches Layer 2 device Multi-port bridge Make decisions based on MAC addresses The purpose of a switch is to concentrate connectivity, while making data transmission more efficient.

33. Routers Layer 3 device (IP address) Connect different Layer 2 technologies Ethernet, Token-ring, and FDDI. To examine incoming packets (Layer 3 data), choose the best path for them through the network, and then switch them to the proper outgoing port

37. Clouds There is a way to connect to that other network (the Internet), but does not supply all the details of either the connection or the network A collection of devices that operate at all levels of the OSI model, it is classified as a Layer 1-7 device

39. Network segments Layer 1 segment A segment identifies the Layer 1 media that is the common path for data transmission in a LAN Repeater is the separator Layer 2 segment

40. Segments A segment as a collision domain Segment: a Layer 4 PDU

42. Evolution of Network Devices Evolution of network devices Milestones in the history of networking Evolution of networking devices and the OSI layers

46. Devices and the OSI layers Hosts & servers operate at Layers 2-7 Layer 1 Transceivers, repeaters, and hubs Patch cables, patch panels, and other interconnection components Layer 1,2: NIC, Bridge, Switch Layer 1,2,3: Router

49. Basics of Data Flow Through LANs Encapsulation and packets review Packet flow through Layer 1 devices Packet flow through Layer 2 devices Packet flow through Layer 3 devices Packet flow through clouds and through Layer 1-7 devices A data packet's path through all seven layers of a LAN

50. Encapsulation & packets review Transport layer: segments Sequence numbers (order) Network layer: packet Destination & source address Data Link layer: frame Add the source/destination(MAC) address

51. Encapsulation & packets review The bottom three layers (Network, Data Link, Physical) The primary movers of data across an Intranet or Internet. The gateway uses all seven of the OSI layers

54. Layer 1 devices are passive (e.g. plugs, connectors, jacks, patch panels, physical media)

57. AUI port to RJ-45 RJ-45 electrical to ST Optical

62. selection of best path and actual switching

63. Gateway SNALAN

74. Building LANs

78. Summary LAN devices, such as routers, switches and hubs Evolution of networking devices basics of data flow basics related to building LANs