2. Copyright 2001 Global Wireless Education Consortium 1 1 BASIC DATA NETWORKS

3. Copyright 2001 Global Wireless Education Consortium 2 Bandwidth Narrowband 0 - 64 kbps Wideband 64 Kbps - 45 Mbps Broadband 45 Mbps and Beyond X.25 Frame Relay ATM SMDS Token Ring FDDI x xT-1, PRI T- 3 SONET LAN Backbone Network Access Network Hierarchy and Protocols IP Ethernet

4. Copyright 2001 Global Wireless Education Consortium 3 Definition: Topology The Physical and Logical Way the Network Elements are Connected

5. Copyright 2001 Global Wireless Education Consortium 4 Legend Device on LAN = Bus StarRing Local Area Network (LAN) Topologies

6. Copyright 2001 Global Wireless Education Consortium 5 LAN Topologies Legend Device on LAN = Bus Example: Ethernet CSM/CD: Carrier Sense Multiple Access/ Collision Detection Send Data Units out unless you detect another data unit.

7. Copyright 2001 Global Wireless Education Consortium 6 LAN Topologies Ring Example: Token Ring Send data units when you possess the token Token: Special Type of Data Unit

8. Copyright 2001 Global Wireless Education Consortium 7 LAN Standards IEEE 802.1 INTERNETWORKING lOGICAL LINK CONTRO (LLC) OSI LAYERS 3-7 OSI LAYER 2 OSI LAYER 1 PHYSICAL MEDIUM ACCESS CONTROL (MAC) IEEE 802.2 TYPE 1 - UNACKNOWLEDGED CONNECTIONLESS SERVICE TYPE 2 - CONNECTION MODE SERVICE TYPE 3 - ACKNOWLEDGED CONNECTIONLESS SERVICE 802.3 CSMA/CD (ETHERNET) 802.4 TOKEN BUS 802.5 TOKEN RING 802.6 DQDB (MAN) BASEBAND COAXIAL AND UNSHIELDED TWISTED PAIR BROADBAND COAXIAL BROADBAND COAXIAL OPTICAL FIBER SHIELDED OR UNSHIELDED TWISTED PAIR OPTICAL FIBER OR COAXIAL CABLE

9. Copyright 2001 Global Wireless Education Consortium 8 Access Networks: Entry to Wide Area Network (WAN) Customer Premises Bridge-Router Access Network Enter via port on LAN router

10. Copyright 2001 Global Wireless Education Consortium 9 Data Flow in an X.25 Network Protocol Layers Involved in Data Transfer 321321 Switch ASwitch C X.25 Network Switch B

11. Copyright 2001 Global Wireless Education Consortium 10 Data Flow in a Frame Relay Network Frame Relay Network Protocol Layers Involved in Data Transfer 321321 Switch ASwitch CSwitch B

12. Copyright 2001 Global Wireless Education Consortium 1 Backbone Networks High Speed Interconnection of Networks

13. Copyright 2001 Global Wireless Education Consortium 12 ATM Cell Structure HeaderPayload 48 Octets5 Octets 1 2 3 4 5 Octet 8 7 6 5 4 3 2 1 Bit Position GFC VPI VCI PTI HEC VCI = Virtual Channel ID VPI = Virtual Path ID PTI = Payload Type Identifier GFC = Generic Flow Control CLP = Cell Loss Priority HEC = Header Error Control CLPCLP Backbone Example: Asynchronous Transfer Mode (ATM)

14. Copyright 2001 Global Wireless Education Consortium 13 ATM Users Receive as Much Bandwidth as They Require PYTHON WITH EXPANDABLE SKIN (BANDWIDTH)

15. Copyright 2001 Global Wireless Education Consortium 14 User 1 User 2 User 3 125  sec250  sec375  sec500  sec Asynchronous means data units (cells) are placed on the network as the application requires User 1 User 2 User 3

16. Copyright 2001 Global Wireless Education Consortium 15 OPEN SYSTEMS INTERFACE (OSI) MODEL Application Presentation Session Transport Network Data Link Physical Application Presentation Session Transport Network Data Link Physical Network Data Link Network Node 7 6 5 4 3 2 1 7 6 5 4 3 2 1

17. Copyright 2001 Global Wireless Education Consortium 16 Wireless OSI Model Application Presentation Session Transport Network Data Link Physical Application Presentation Session Transport Network Data Link Physical Network Data Link Network Node 7 6 5 4 3 2 1 7 6 5 4 3 2 1 MESSAGES USE BOTTOM 3 LAYERS

18. Copyright 2001 Global Wireless Education Consortium 17

19. Copyright 2001 Global Wireless Education Consortium 18 The OSI Model Application Presentation Session Transport Network Datalink Physical Header User Info 1 7 6 5 4 3 2 A Set of Rules

20. Copyright 2001 Global Wireless Education Consortium 19 Layer Details – Layer 1 Network Data Link Physical Application Presentation Session Transport Transmits bits received from the Data Link layer across the transmission medium

21. Copyright 2001 Global Wireless Education Consortium 20 Layer Details – Layer 2 Data Link Physical Sequences messages and checks for errors between adjacent link stations Transmits bits received from the Data Link layer across the transmission medium Network Application Presentation Session Transport

22. Copyright 2001 Global Wireless Education Consortium 21 Layer Details – Layer 3 Network Data Link Physical Fragments or “packetizes” messages, and routes them to the proper destination Sequences messages and checks for errors between adjacent link stations Transmits bits received from the Data Link layer across the transmission medium Application Presentation Session Transport

23. Copyright 2001 Global Wireless Education Consortium 2 Layer Details – Layer 4 Network Data Link Physical Transport Fragments or “packetizes” messages, and routes them to the proper destination Sequences messages and checks for errors between adjacent link stations Transmits bits received from the Data Link layer across the transmission medium Provides multiplexing, network connection management, quality of service, etc. Application Presentation Session

24. Copyright 2001 Global Wireless Education Consortium 23 HeaderInformation Packet Format

25. Copyright 2001 Global Wireless Education Consortium 24 Header User Data Perhaps a Trailer Store and Forward Packet Switched Routing

26. Copyright 2001 Global Wireless Education Consortium 25 HeaderInformation Packet Format Layer 2 InfoLayer 3-5 InfoLayer 2 InfoFlag Message Format Types of Protocol Data Unit Being Sent Through a Packet Switched Network Protocol Data Units

27. Copyright 2001 Global Wireless Education Consortium 26 HeaderTrailerUser Data Protocol Data Unit Routing Fields

28. Copyright 2001 Global Wireless Education Consortium 27 ROUTER NODE B DATA CC BC NODE A NODE C Destination Node Won’t Change Address of Next Node on Route Router Stores Packet, Reads Destination Information And Forwards To The Next Node Routers Routing Packets Final Path

29. Data Switch Routing Example Ethernet Switch –Receives Ethernet frame –Looks up 6-byte Destination Address in a Forwarding Table –Sends frame out only the port associated with the Destination Address

30. Ethernet Switch

31. Copyright 2001 Global Wireless Education Consortium 30 Packet Switched Network Routing

32. Copyright 2001 Global Wireless Education Consortium 31 Data Network Devices & the OSI Reference Model Gateways Routers Switches Hubs Bridges Repeaters

33. Copyright 2001 Global Wireless Education Consortium 32 REPEATER LAYER 1 PHYSICAL I PHYSICALLY REPEAT AND REGENERATE BITS FOR MY OWN LAN

34. Copyright 2001 Global Wireless Education Consortium 3 BRIDGE LAYER 2 DATA LINK LAYER I LINK DATA FRAMES BY BRIDGING BETWEEN IS LAN D S. LAN 1 LAN 2

35. Copyright 2001 Global Wireless Education Consortium 34 HUB LAYER 2 DATA LINK LAYER I ROUTE PACKETS BETWEEN IS LAN D S WITH COMMON PROTOCOLS USER

36. Copyright 2001 Global Wireless Education Consortium 35 DATA SWITCH LAYER 2 DATA LINK LAYER I ROUTE PACKETS BETWEEN PORTS PACKETS ARE NOT SENT TO EVERY PORT (ONLY TO THE DESTINATION PORT) USER

37. Copyright 2001 Global Wireless Education Consortium 36 ROUTER LAYER 3 NETWORK LAYER I ROUTE PACKETS BETWEEN IS LAN D S WITH COMMON PROTOCOLS

38. Copyright 2001 Global Wireless Education Consortium 37 GATEWAY LAYER 3+ I CONVERT PROTOCOLS BETWEEN IS LAN D S SYNCHRONOUS TO ASYNCHRONOUS SYNCASYNC

39. Copyright 2001 Global Wireless Education Consortium 38 Data Network Devices in Data Network Applications

40. Copyright 2001 Global Wireless Education Consortium 39 Router Carrier Network Router Chicago Router LAN Hub Client Detroit Router LAN Hub Server Customer Network Customer Network Access Line Access Line Typical Packet Data Services

41. Copyright 2001 Global Wireless Education Consortium 40 Routers modify layer 2 frame headers & trailers so packet can travel end-to-end over many links. They provide Gateways into and out of the PSTN. IP packets / TR frames IP packets / PPP frames Router or Gateway modifies frame IP packets / TR frames Packets, Routers and the PSTN

42. Copyright 2001 Global Wireless Education Consortium 41 Combined Network CMTS MSC TELCO NIU Host Digital Terminal SS7 Internet Intranet or Public Data Network Average ResidencePower Residence Corporate ACorporate B Trunks to Telco Switch Gateway

43. Copyright 2001 Global Wireless Education Consortium 42 IP Telephony Using a Computer as the Terminal PSTNInternet CODEC Gateway Router Cable Modem Microphone

44. Copyright 2001 Global Wireless Education Consortium 43 PSTNInternet CODEC Gateway Router IP Telephony Generates Mobile Like Traffic Cable Modem Telephone Adapter

45. Copyright 2001 Global Wireless Education Consortium 4 Committed Information Rate (CIR) Data Collisions Protocol Analyzers Detecting and Fixing Errors

46. Copyright 2001 Global Wireless Education Consortium 45

47. Copyright 2001 Global Wireless Education Consortium 46 Longitudinal Redundancy Check (LRC) Block Parity Character Checksum XMODEM Checksum New Terms

48. Copyright 2001 Global Wireless Education Consortium 47

49. Copyright 2001 Global Wireless Education Consortium 48 Automatic Repeat Request (ARQ) Acceptance (ACK) Reject (NAK)

50. Copyright 2001 Global Wireless Education Consortium 49 Forward Error Correction (FEC)

51. Copyright 2001 Global Wireless Education Consortium 50 Types of Digital Error Measurement Bit Error Rate (BER) Block Error Rate (BLER)

52. Copyright 2001 Global Wireless Education Consortium 51 Errored Seconds Severely Errored Seconds

53. Copyright 2001 Global Wireless Education Consortium 52

54. Copyright 2001 Global Wireless Education Consortium 53 Summary Types of Data Networks OSI Reference Model Packet Structures Routing Devices Applications Detecting And Fixing Errors