1. © 1999, Cisco Systems, Inc. 2-1 Chapter 2 Internetworking Concepts Overview

2. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-2

3. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-3 Objectives On completion of this chapter, you will be able to perform the following tasks: Describe how data traffic is exchanged between source and destination devices Identify the roles and functions of a hub, switch, and router, and where they best fit in the network Select the appropriate Cisco equipment for a given set of network requirements

4. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-4 Defining Components of the Network Main OfficeBranch Office Home Office Mobile Users Internet

5. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-5 Floor 2 Floor 1 Server Farm Defining the Components of a Network (cont.) Branch Office Telecommuter ISDN RemoteCampus

6. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-6 Network Structure Defined by Hierarchy Distribution Layer Core Layer Access Layer

7. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-7 Access Layer Characteristics End station entry point to the network Access Layer

8. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-8 Distribution Layer Characteristics Access Layer Aggregation Point Routes traffic Broadcast/Multicast Domains Media Translation Security Possible point for remote access Distribution Layer

9. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-9 Core Layer Characteristics Fast transport to enterprise services No packet manipulation Core Layer

10. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-10 OSI Model Overview Application (Upper) Layers Session Presentation Application

11. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-11 OSI Model Overview Data Flow Layers Transport Layer Data Link Network Layer Physical Application (Upper) Layers Session Presentation Application

12. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-12 Role of Application Layers Telnet HTTP User Interface EXAMPLES Application

13. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-13 Telnet HTTP ASCII EBCDIC JPEG User Interface How data is presented Special processing such as encryption EXAMPLES Presentation Application Role of Application Layers

14. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-14 Telnet HTTP ASCII EBCDIC JPEG Keeping different applications’ data separate User Interface How data is presented Special processing such as encryption Operating System/ Application Access Scheduling EXAMPLES Session Presentation Application Role of Application Layers

15. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-15 Keeping different applications’ data separate User Interface How data is presented Special processing such as encryption Telnet HTTP ASCII EBCDIC JPEG Operating System/ Application Access Scheduling Transport Layer Data Link Network Layer Physical EXAMPLES Session Presentation Application Role of Application Layers

16. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-16 Role of Data Flow Layers EIA/TIA-232 V.35 EXAMPLES Physical Move bits between devices Specifies voltage, wire speed and pin-out cables

17. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-17 802.3 / 802.2 HDLC EIA/TIA-232 V.35 EXAMPLES Role of Data Flow Layers Data Link Physical Combines bits into bytes and bytes into frames Access to media using MAC address Error detection not correction Move bits between devices Specifies voltage, wire speed and pin-out cables

18. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-18 802.3 / 802.2 HDLC EIA/TIA-232 V.35 IP IPX EXAMPLES Role of Data Flow Layers Network Data Link Physical Combines bits into bytes and bytes into frames Access to media using MAC address Error detection not correction Move bits between devices Specifies voltage, wire speed and pin-out cables Provide logical addressing which routers use for path determination

19. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-19 TCP UDP SPX 802.3 / 802.2 HDLC EIA/TIA-232 V.35 IP IPX EXAMPLES Role of Data Flow Layers Transport Data Link Physical Reliable or unreliable delivery Error correction before retransmit Combines bits into bytes and bytes into frames Access to media using MAC address Error detection not correction Move bits between devices Specifies voltage, wire speed and pin-out cables Network Provide logical addressing which routers use for path determination

20. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-20 TCP UDP SPX 802.3 / 802.2 HDLC EIA/TIA-232 V.35 IP IPX Presentation Application Session EXAMPLES Role of Data Flow Layers Reliable or unreliable delivery Error correction before retransmit Combines bits into bytes and bytes into frames Access to media using MAC address Error detection not correction Move bits between devices Specifies voltage, wire speed and pin-out cables Transport Data Link Physical Network Provide logical addressing which routers use for path determination

21. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-21 Encapsulating Data Transport Data Link Physical Network Upper Layer Data TCP Header DataIP Header DataLLC Header 0101110101001000010 DataMAC Header Presentation Application Session Segment Packet Bits Frame PDU FCS

22. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-22 Upper Layer Data De-encapsulating Data LLC Hdr + IP + TCP + Upper Layer Data MAC Header IP + TCP + Upper Layer Data LLC Header TCP+ Upper Layer Data IP Header Upper Layer Data TCP Header 0101110101001000010 Transport Data Link Physical Network Presentation Application Session

23. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-23 Application Presentation Session Transport Network Data Link Physical OSI Model PDUFunctional ResponsibilitiesExamples Written Exercise: OSI Model

24. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-24 Physical Layer Functions Defines Media type Connector type Signaling type Ethernet 802.3 V.35 Physical EIA/TIA-232

25. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-25 Physical Layer: Ethernet/802.3 H ub Hosts Host 10Base2—Thick Ethernet 10Base5—Thick Ethernet 10BaseT—Twisted Pair

26. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-26 Hubs Operate at Physical layer ABCD Physical All devices in the same collision domain All devices in the same broadcast domain Devices share the same bandwidth

27. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-27 Hubs: One Collision Domain More end stations means more collisions CSMA/CD is used

28. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-28 Data Link layer Functions Defines Physical source and destination addresses Higher layer protocol (Service Access Point) associated with frame Network topology Frame sequencing Flow control Connection-oriented or connectionless Data Link Physical EIA/TIA-232 v.35 Ethernet Frame Relay HDLC 802.2 802.3

29. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-29 Data Source addFCS Length Dest add Variable2664 0000.0C xx.xxxx Vendor assigned IEEE assigned MAC Layer - 802.3 Data Link Layer Functions (cont.) Preamble Ethernet II uses “Type” here and does not use 802.2. MAC Address 8# Bytes

30. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-30 Data Dest SAP Source SAP DataSource addFCSLengthDest add Variable11 802.2 (SAP) MAC Layer - 802.3 Data Link Layer Functions (cont.) Ctrl 1 or 2 32 Preamble Data Dest SAP AA Source SAP AA Variable11 802.2 (SNAP) Ctrl 03 1 or 2 OR OUI ID Type

31. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-31 Each segment has its own collision domain All segments are in the same broadcast domain Data Link Switches and Bridges Operate at Data Link Layer OR 123124

32. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-32 Switches Each segment has its own collision domain Broadcasts are forwarded to all segments Memory Switch

33. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-33 Network Layer Functions Defines logical source and destination addresses associated with a specific protocol Defines paths through network Interconnects multiple data links Network IP, IPX Data Link Physical EIA/TIA-232 v.35 Ethernet Frame Relay HDLC 802.2 802.3

34. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-34 Data Source address Destination address IP Network Layer Functions (cont.) Header 172.15.1.1 NodeNetwork Logical Address Network Layer End Station Packet

35. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-35 Network Layer Functions (cont.) 11111111 00000000 10101100 00010000 01111010 11001100 Binary Mask Binary Address 172.16.122.204 255.255.0.0 17216122204 255 AddressMask 25500 NetworkHost

36. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-36 Routing Table NETINTMetric 1 2 4 S0 E0 1 0 0 1.04.0 1.3 E0 4.3 S0 2.2 E0 2.1 S0 4.1 4.2 1.1 1.2 Routing Table NETINTMetric 1 2 4 E0 S0 0 0 1 Logical addressing allows for hierarchical network Configuration required Uses configured information to identify paths to networks Network Layer Functions (cont.)

37. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-37 Routers: Operate at the Network Layer Broadcast control Multicast control Optimal path determination Traffic management Logical addressing Connects to WAN services

38. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-38 Using Routers to Provide Remote Access Internet Telecommuter Branch Office Modem or ISDN TA Mobile User Main Office

39. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-39 Transport Layer Functions Distinguishes between upper layer applications Establishes end-to-end connectivity between applications Defines flow control Provides reliable or unreliable services for data transfer Network IPXIP Transport SPXTCPUDP

40. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-40 Reliable Transport Layer Functions Synchronize Acknowledge, Synchronize Acknowledge Data Transfer (Send Segments) SenderReceiver Connection Established

41. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-41 Network Device Domains HubBridgeSwitchRouter Collision Domains: 1 4 4 4 Broadcast Domains: 1 1 1 4

42. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-42 Choosing a Cisco Product Distribution Layer Core Layer Access Layer

43. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-43 Product Selection Considerations Provides functionality and features you need today Capacity and performance Easy installation and centralized management Provides network resiliency Investment protection in existing infrastructure Migration path for change and growth Seamless access for mobile users and branch offices

44. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-44 First select WAN technology solutions based on the following: –Availability of service –Bandwidth requirement –Cost Second, choose products that support selected WAN solutions Product Selection Considerations (cont.) Cost per Month Usage Leased Line, T1 Modem/ISDN Frame Relay 0

45. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-45 Product Selection Considerations (cont.) 1544 128 64 56 19.2 9.6 4.8 Determine applications that you want to run ISDN, Frame Relay Old Modem Telnet New Modem Web Browsing Voice Video, Multimedia E-Mail, File Transfer Leased Line, Frame Relay, XDSL kbps

46. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-46 Selection Issues: Need for 10 Mbps or 100 Mbps on media Port density Need for management console Easy Operations Cisco 1500 Micro Hub Cisco FastHub300 Cisco 1528 Micro Hub 10/100 Cisco FastHub400 Cisco FastHub200 Cisco FastHub100 Cisco Hub Products

47. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-47 Selection Issues: Need for 10 Mbps, 100 Mbps, or 1000 Mbps on media Need for trunking and inter-switch links Workgroup segmentation (VLANs) Port density needs Different user interfaces Desktop/Workgroup Solutions Wiring Closet/Backbone Solutions Cisco 1548 Micro Switch 10/100 Catalyst 3000 series Catalyst 2900 series XL Catalyst 1900/2820 series Catalyst 2900 series Catalyst 5000 series Catalyst 8500 series Catalyst Switch Products

48. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-48 Do Not Delete—Overflow Text on Notes Page

49. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-49 Selection Issues: Scale of the routing features needed Port density/variety requirements Capacity and performance Common user interface Cisco 700/800 Series Cisco 1600/1700 Series Cisco 2500 Series Cisco 3600 Series AS 5000 Series Small Office Solutions Branch Office Solutions Central Site Solutions Cisco 12000 GSR Series Cisco 4000 Series Cisco 7000 Series Home Office Solutions Cisco 2600 Series Cisco Router Products

50. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-50 Do Not Delete—Overflow Text on Notes Page

51. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-51 Visual Objective Use the product selection tool to select Cisco Equipment

52. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-52 Summary After completing this chapter, you should be able to perform the following tasks: Describe how data moves through a network Identify the roles and functions of routers, switches and hubs, and specify where each device best fits in the network Select the appropriate Cisco equipment for a network that combines switching, routing and remote access requirements

53. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-53 1. What are some of the advantages of using the OSI model in a networking environment? 2. Describe the encapsulation process. 3. How many broadcast and collision domains are on a hub? Review Questions

54. © 1999, Cisco Systems, Inc. www.cisco.com ICND—2-54 Blank for pagination