1. OSI Model Overview Application (Upper) Layers Session Presentation Application

2. OSI Model Overview Data Flow Layers Transport Data-Link Network Physical Application (Upper) Layers Session Presentation Application

3. Role of Application Layers Telnet FTP User Interface Examples Application

4. Telnet FTP ASCII EBCDIC JPEG User Interface How data is presented Special processing such as encryption Examples Presentation Application Role of Application Layers

5. Telnet FTP 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

6. Keeping different applications’ data separate User interface How data is presented Special processing such as encryption Telnet FTP ASCII EBCDIC JPEG Operating System/ Application Access Scheduling Transport Data-Link Network Physical Examples Session Presentation Application Role of Application Layers

7. Role of Data Flow Layers EIA/TIA-232 V.35 Examples Physical Move bits between devices Specifies voltage, wire speed, and pin-out cables

8. 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

9. 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 that routers use for path determination

10. 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 that routers use for path determination

11. 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 pinout cables Transport Data-Link Physical Network Provide logical addressing that routers use for path determination

12. 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

13. 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

14. Application Presentation Session Transport Network Data-Link Physical OSI Model PDUFunctional ResponsibilitiesExamples Written Exercise 1: OSI Model

15. Physical Layer Functions Defines Media type Connector type Signaling type Ethernet 802.3 V.35 Physical EIA/TIA-232

16. Physical Layer: Ethernet/802.3 Hub Hosts Host 10Base2—Thin Ethernet 10Base5—Thick Ethernet 10BaseT—Twisted Pair

17. Hubs Operate at Physical Layer ABCD Physical All devices are in the same collision domain. All devices are in the same broadcast domain. Devices share the same bandwidth.

18. Hubs: One Collision Domain More end stations means more collisions. CSMA/CD is used.

19. 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

20. Data Source Address FCS Length Destination Address 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 Number of Bytes

21. Data Destination SAP Source SAP Data Source Address FCSLength Destination Address Variable11 802.2 (SAP) MAC Layer—802.3 Data-Link Layer Functions (cont.) Control 1 or 2 32 Preamble Data Destination SAP AA Source SAP AA Variable11 802.2 (SNAP) Control 03 1 or 2 OR OUI ID Type Number of Bytes

22. 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

23. Switches Each segment is its own collision domain. Broadcasts are forwarded to all segments. Memory Switch

24. 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

25. Data Source Address Destination Address IP Network Layer Functions (cont.) Header 172.15.1.1 NodeNetwork Logical Address Network Layer End-Station Packet

26. 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

27. 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 is required. Configured information identifies paths to networks. Network Layer Functions (cont.)

28. Routers: Operate at the Network Layer Broadcast control Multicast control Optimal path determination Traffic management Logical addressing Connects to WAN services

29. Using Routers to Provide Remote Access Internet Telecommuter Branch Office Modem or ISDN Terminal Adapter Mobile User Main Office

30. 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

31. Reliable Transport Layer Functions Synchronize Acknowledge, Synchronize Acknowledge Data Transfer (Send Segments) SenderReceiver Connection Established

32. Network Device Domains HubBridgeSwitchRouter Collision Domains: 1 4 4 4 Broadcast Domains: 1 1 1 4

33. Choosing a Cisco Product Distribution Layer Core Layer Access Layer

34. Product Selection Considerations Functionality and features you need today Capacity and performance Easy installation and centralized management Network resiliency Investment protection in existing infrastructure Migration path for change and growth Seamless access for mobile users and branch offices

35. 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

36. 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

37. 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 FastHub®100 Cisco Hub Products

38. 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 Cisco Switch Products

39. 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

40. 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