CIS121

1. Networking Basics CIS121

2. Network Terminology • History • Network • WAN • LAN • WLAN • MAN • PAN • SAN • Peer-to-Peer Network • Client-Server Network • Node • Segment • Network Topologies • LAN Access Methods • Networking Protocols • NIC • Hub • Switch • Router • Bridge • Firewall • Access Point • Multi-function Device

3. Before Networks…. • To Print PC had to have a Printer Attached to It OR File had to be Sneaker Netted to a PC that did have a Printer

4. Before Networks… • To Share Messages or Files • Yell Your Message Or Mail Your Message

5. Before Networks… • Under-utilized Resources • Duplicate Devices • Duplicate Data • Expensive

6. Network Definition • Two or More Computers Connected by a Communication Media • Allows Information and Resources to be Shared by Network Users

7. Network Types…WAN • WAN – Wide Area Network • Computer Network that Spans Large Geographic Area • Typically Uses Common-Carrier Lines or Satellites for Connections • TheInternet is the Largest WAN • See fairly recent Internet World-Wide Connections, click here.

8. Network Types…LAN • LAN – Local Area Network Internet • Network devices are within a small geographic area such as office building, school or home • Typically does NOT utilize Common Carrier lines. • May include one or more LANs Firewall Router Hub/Switch

9. Network Types…WLAN • Wireless Local Area Network • Radio Frequency (RF) Technology Used to Transmit and Receive Data Over Airways • No Physical Media Required for Connection to LAN • May Require Security Password for Connection Click within image to Start or Pause Animation

10. Network Types…MAN • MAN – Metropolitan Area Network Internet • Network that expands a larger geographic area than LAN, such as a city or campus, and smaller geographic area than WAN • Likely does utilize some Common Carrier lines. • Includes one or more LANs Router Building 2 Router Building 1 Router Building 3 Router Building 4

11. Network Types…PAN • PAN – Personal Area Network • Interconnection of devices such as laptops, smart phones, PDAs, portable printers, that are in very close proximity (10-15 meters) of person. • Can include both wired and wireless devices. • Home network could be considered a PAN

12. Network Types…Peer-to-Peer • Peer-to-Peer Network • All Computers on Network are Equal • Peers share resources Equally • Files • Applications • Printers • Disk Storage • No Dedicated Servers • No Administrator Required • Easy to Set Up • Less Expensive than Client-Server Model Workstations Hub

13. Network Types…Client-Server • Client-Server Network • One or many Dedicated Servers for: • Files • Applications • E-mail • Web Services • DHCP Server • Print • One or many clients that: • Run Applications • Access Services of Server • More Expensive than Peer-to-Peer Network • More Secure than Peer-to-Peer Workstations Hub Server

14. Network Types…SAN • SAN – Storage Area Network Disk Volumes • Network of Storage Devices. • Accessible by any computer on the network • Storage devices appear to be locally attached to requesting devices. Virtual Server Host Virtual Server Host Storage Area Network Disk Arrays Storage Server

15. Network Definitions….Node • Any PC or Peripheral Connected to the Network Click within image to Start or Pause Animation

16. Network Definitions…Segment • Portion of LAN Separated from Other Parts of LAN via Router, Switch or Bridge • Networks are segmented to improve performance and increase security. Click within image to Start or Pause Animation

17. LAN Network Topologies • Topology: Physical Layout of Network • Most Popular Topologies • BUS • Network Devices are Connected to Single Cable • Physical Layout– Line • STAR • Network Devices Connect to Central Hub/Switch • Physical Layout– Star • RING • Network Devices Connect to Central Hub/Multi-Station Access Unit • Physical Layout – Star • Logical Layout – Ring • MESH • Each Network Device Connected to Every Other Device in Network • There are Other Topologies and Combinations of the Above

18. LAN Topologies…BUS • Original Network Topology Used in 1980s • Devices are Attached to One Cable • If a Device Crashes, all Devices on Cable are Inoperable • BUS Topology is Seldom Used Today

19. LAN Topologies…Ring • Logical layout is a Ring • Physical layout is actually a Star due to Hub or Multi-station Access Unit that Connects Network Devices • Ring Topology is Seldom Used Today

20. LAN Topologies…Star • Star – Physical Layout Looks Like a Star • Central Hub/Switch Connects Network Devices • Most Prevalent LAN Topology Used Today

21. LAN Topologies…Mesh • Mesh– Each Device in Network is Connected to Every Other Device in Network • Only Used for Small Networks

22. LAN Access Methods • Defines How a Network Device Can Access a Shared Network to Transmit Data. • Primary Access Methods are: • CSMA/CD (Carrier Sense Multiple Access/Collision Detection) • Token Passing

23. LAN Access Methods…CSMA/CD • Also called Ethernet • Most Prevalent LAN Access Method • Network Node Listens to cable for carrier tone and transmits data when no other devices are transmitting. • Message is broadcast to all devices on network • Message is received by device with destination address. • If two or more devices sense an idle network and attempt to transmit at same time, a collision will occur. • Each device stops transmission • Each device waits a period of time to re-transmit

24. LAN Access Methods…CSMA/CD Click within image to start or Pause Animation

25. LAN Access Methods…CSMA/CD Collision Click within image to Start or Pause Animation

26. CSMA/CD on a Star Topology Click within image to Start or Pause Animation

27. LAN Access Methods…Token Passing Click within image to Start or Pause Animation

28. Protocol • Set of rules or standards by which computers communicate over a network. • Two computers must be using the same protocol for communication to happen • Like a language; to communicate, two people need to be speaking the same language • Network media supports multiple protocols at the same time • Each protocol specifies how a message is to be formatted.

29. Common Network Protocols • TCP/IP protocol suite • TCP – Transmission Control Protocol • Used by most Internet applications • Provides reliable transfer of messages from one computer program to another computer program • IPv4– Internet Protocol Version 4. • Allows dissimilar Internet hosts to connect to each other • Specifies how packets are formatted & routed • Specifies addressing format • Supports 32-bit IP addresses (232 or 4,294,967,296 Internet addresses)

30. Common Network Protocols • IPv6 – Internet Protocol Version 6 • Supports 128-bit Internet addresses (2128 ) • Needed because of IPv4 number of address limitation. • ARP – Address Resolution Protocol • Used to convert IP addresses into Data Link Control (DLC) or Media Access Control (MAC) addresses. • HTTP – HyperText Transfer Protocol • Primary protocol used for display of Web pages • HTTPS -- Secure version of HTTP • HTML – HyperText Markup Language • Used to format Web pages

31. Common Network Protocols • FTP – File Transfer Protocol • Used to transfer or copy file(s) from one computer to another computer. • DNS– Domain Name System • Responsible for converting IP addresses into a meaningful name that humans can better understand • www.pcc.edu = 209.152.46.213 • DHCP – Dynamic Host Configuration Protocol • Automatically assigns IP addresses to network computers via DHCP server

32. Common Network Protocols • POP3 – Post Office Protocol Version 3 • Protocol used to retrieve user’s e-mail from a remote e-mail server • IMAP – Internet Message Access Protocol • Other protocol used to retrieve e-mail messages from a remote e-mail server • SMTP– Simple Mail Transfer Protocol • Used for sending e-mail messages from a computer Click here for a more complete list of network protocols.

33. Networking Devices Bridge Gateway Access Point Firewall Repeater • Network Interface Card (NIC) • Hub • Switch • Router

34. Networking Devices…NIC • Every node on a network must have a NIC • Wired or Wireless • Most desk-top PCs sold today have built-in wired Ethernet NICs installed • Most laptops sold today have built-in wired and wireless Ethernet NICs installed Wired NICs connect to Network through the RJ45 port and Cat 5 UTP Cable • A computer can have more than one NIC installed • NICs Come as: • Expansion Cards • Express Cards • USB • PC Card

35. Networking Devices…NIC con’t. • Usually designed for a particular network, protocol and media • Ethernet is most prevalent LAN protocol • Most Common Wired Media -- Category 5/5e/6 Unshielded Twisted Pair (UTP) wire • Other Medias • Wireless • Fiber • Coax Cable • PowerLine Multimode fiber Coax Cable Cat 5e

36. Networking Devices…Modem • DSL Modem • Used to connect a router on LAN or single computer to a common carrier provided Digital Subscriber Line • Modulates/demodulates between digital data on the computer side and high-frequency tones on the DSL side. • Cable Modem • Used to connect router on LAN or single computer to TV cable network

37. Networking Devices…Modem con’t. • Modems • Used in home and small business networks for broadband connection • Large business networks typically connect to Internet through direct-connect or leased lines and router. • Modem connects directly to DSL line or Cable Network Internet Router Modem Home Network Provider’s Connection

38. Networking Devices…Hub • Device for Connecting Multiple Network Devices Together in One LAN • Hubs work at Layer 1 (physical) of the OSI Model • Do NOT support Sophisticated Networking • Do NOT Read Data Passing Through Them • Receives Packets and Broadcasts to ALL Devices connected to Hub • Only routes data that uses protocol that hub is programmed for • Hubs Usually have 4 or 8 ports

39. Networking Devices…Hub con’t. • Passive Hub • Do Not Amplify Signal of Incoming Packets Before Broadcasting to Devices Connected to Hub • Dumbest of the Hub Types • Active Hub • DO Amplify Incoming Signals Before Broadcasting to Devices Connected to Hub • Can also be called a Concentrator or Multiport Repeater • Intelligent Hub • Usually Stackable • Includes Input and Output Ports so Hubs can be Connected Together • Supports More Devices on the Network • Usually Includes Remote Management Support of VLANs and SNMP • May also Support Bridging, Routing and Switching • Hubs work at Layer 1 of the OSI Model • Devices are Typically Connected via Cat5/6 Cables with RJ45 Connectors • Do NOT support Sophisticated Networking • Do NOT Read Data Passing Through Them • Receives Packets and Broadcasts to ALL Devices on Network

40. Networking Devices…Switch • Device for Connecting Multiple Network Devices in LAN • Most Switches operate at Layer 2 (data link) of the OSI Model • Devices are Typically Connected via Cat5/6 Cables with RJ45 Connectors • Contains More Intelligence than Hubs • Can Read Incoming Packets for Source & Destination Addresses • A Switch Keeps a Forwarding Table of all Device Mac Addresses that are attached to the Switch • Mac (Media Access Control) Address is a Unique Identifier assigned to Every Network Interface Card (NIC) • Forward Packets to Destination Device (does not broadcast) • Conserves Network Bandwidth

41. Networking Devices…Switch • May be Managed or Unmanaged • Multilayer Switches • Also Process Data at Layer 3 (network), Layer 4 (transport) and/or Layer 7 (application) of OSI Model • Ethernet Implementation is Most Common Type • May support bridging functions by supporting connection of different LANs

42. Networking Devices…Switch • Device for Connecting Multiple Network Devices in LAN • Most Switches operate at Layer 2 (data link) of the OSI Model • Devices are Typically Connected via Cat5/6 Cables with RJ45 Connectors • Contains More Intelligence than Hubs • Can Read Incoming Packets for Source & Destination Addresses • Forward Packets to Destination Device (does not broadcast) • Conserves Network Bandwidth

43. Switch Animation

44. Networking Devices…Router • Routes or forwards messages (data packets) between networks • Each router contains routing • Includes Source & Destination IP addresses of Devices connected to it. • Used to filter traffic • Find best route from source to destination for packet • Operates at Layer 3 (network) of the OSI Model • More sophisticated than Switch or Hub • Can also be used to connect Networks

45. Router Animation Click within image to Start or Pause Animation

46. Networking Devices…Bridge • Connect two different Segments of a Network Together • Uses Device MAC address to route data to the destination address • Usually Operates at Layer 2 (data link) of the OSI Model • Can be Used to divide one Large LAN into two Segments • Protocol independent – can connect segments that use different protocols or access methods • Single bridge device is old technology • Rarely Used Today • Function is now built into Other Devices

47. Networking Devices…Bridge Click within image to Start or Pause Animation

48. Networking Devices…Firewall • Hardware standalone device and/or software that guards network from unauthorized access • Software built into Operating System • Most routers include a firewall • Proxy servers may include a firewall • Firewall resides between a trusted network and untrusted network • On Corporate network, if local router does not include a firewall, firewall would go between Internet and local router • On Home network, if router does not include a firewall, firewall would go between dsl/cable modem and router. • Uses filters to block incoming packets to trusted network • Table of trusted and/or untrusted IP addresses • Firewall examines each packet for source IP address and port and destination IP address and port • If address and/or port is on untrusted list, packet does not pass firewall. • Can filter based on protocol (ftp, tcp, etc) • Can also block outbound traffic • Can be used to create multiple zones of trust

49. Firewall Animation Click within image to Start or Pause Animation

50. Networking Devices…Wireless Access Point (WAP) • Also called WiFi • Allows wireless devices to connect to a wired LAN or broadband network • Wireless devices communicate via wireless Network Interface Card • Wireless NIC translates digital signals (1s and 0s) into radio signals which are received by WAP. • Wireless NIC receives radio signals from WAP and translates into digital signals (1s and 0s) which are understood by PC.