Unit 2 TCP/IP Network, Transport & Application Layers Chapters 5-7 NT2640.U2.PS1

1. Unit 2TCP/IP Network, Transport & Application Layers Chapters 5-7NT2640.U2.PS1

2. Class Agenda 11/21/16 • Learning Objectives • Unit 2: Presentation and Discussions and Videos • Chapter 5-7 • Discussion on Lab Activities. • Discussion on Assignments. • Break Times. 10 Minutes break in every 1 Hour. • Note: Submit all Assignment and labs due today.

3. Objectives • In this unit, students will demonstrate an: • Understanding of Network Layer Addressing • Understand of Basic IP Routing Concepts • Understanding of Basic IP Subnetting Principles • Understanding of the Differences between and the Features of the Layer 4 Protocols TCP & UDP • Understanding of Basic Network Security Concepts including Common Issues and Defenses • Understanding Tasks Involved in the Installation of Cisco IOS Devices • Understanding the Basic Tasks Involved in the Accessing the Cisco IOS CLI Environment and Utilizing the Help Subsystem

4. Network Layer Addressing and Layer 4 ProtocolsChapters 5 & 6NT2640-U2-PS1 Chapter1 4

5. Routing Logic: PC1 Sending to PC2

6. IPv4 Header

7. Example 19.1 Change the following IPv4 addresses from binary notation to dotted-decimal notation. Solution We replace each group of 8 bits with its equivalent decimal number (see Appendix B) and add dots for separation.

8. Figure 19.2 Finding the classes in binary and dotted-decimal notation

9. Figure 19.7 Configuration and addresses in a subnetted network

10. Using Subnets

11. Address Formats When Subnetting Is Used (Classful)

12. Address Formats When Subnetting Is Used (Classless) • IP addressing with subnetting uses a concept called a subnet mask. A subnet mask helps define the structure of an IP address,

13. Table 19.2 Default masks for classful addressing

14. ROUTING or FORWARDING Forwarding means to place the packet in its route to its destination. Forwarding requires a host or a router to have a routing table. When a host has a packet to send or when a router has received a packet to be forwarded, it looks at this table to find the route to the final destination. Forwarding TechniquesForwarding Process Routing Table

15. Figure 22.2 Route method versus next-hop method

16. Simple Routing Example, with IP Subnets

17. Network Layer Utilities • (ARP) Address Resolution Protocol • (DNS) Domain Name System • (DHCP) Dynamic Host Configuration Protocol • (ICMP) Internet Control Message Protocol used for troubleshooting - Ping & Tracert

18. Chapter 6 Fundamentals of TCP/IP Transport, Applications, and Security

19. TCP/IP Layer 4 Protocols: TCP and UDP

20. Multiplexing Using TCP Port Numbers • The computer might be running many applications, such as a web browser, an e-mail package, or an Internet VoIP application (for example, Skype). • TCP and UDP multiplexing enables the receiving computer to know which application to give the data to.

21. 6-1 MULTIPLEXING Whenever the bandwidth of a medium linking two devices is greater than the bandwidth needs of the devices, the link can be shared. Multiplexing is the set of techniques that allows the simultaneous transmission of multiple signals across a single data link. As data and telecommunications use increases, so does traffic.

22. Figure 6.3 Frequency-division multiplexing

23. Popular Applications and Their Well-Known Port Numbers

24. Connection & Connectionless Protocols • Connection-oriented protocol: A protocol that requires an exchange of messages before data transfer begins or that has a required preestablished correlation between two endpoints • Connectionless protocol: A protocol that does not require an exchange of messages and that does not require a preestablished correlation between two endpoints

25. Firewalls • IDS and IPS • VPN

26. Chapter 7 Operating Cisco Routers

27. Cisco Routers • Cisco routers need to know several pieces of information before they can start routing IP packets. • First, they need to know which of their physical interfaces currently connect to real LANs and WANs. • Next, the router needs to know its IP address and mask for each of these interfaces. • The router can then use each interface’s IP address/mask pair to calculate the subnet ID of the subnet connected to that interface. • Finally, the routers need to advertise information about the subnets, so that all routers learn about all subnets, and can then choose the best route with which to forward packets to reach each subnet.

28. Installing Cisco Routers • Routers collectively provide the main feature of the network layer—the capability to forward packets end-to-end through a network. • Routers forward packets by connecting to various physical network links, like Ethernet, serial links, and Frame Relay, and then using Layer 3 routing logic to choose where to forward each packet. • A typical enterprise network has a few centralized sites as well as lots of smaller remote sites. • To support devices at each site (the computers, IP phones, printers, and other devices), the network includes at least one LAN switch at each site.

29. Detailed Cabling Diagram for the Same Enterprise Network

30. Model 1841 Cisco Integrated Services Router (ISR)

31. Router Installation • Step 1: Connect any LAN cables to the LAN ports. • Step 2: If using an external CSU/DSU, connect the router’s serial interface to the CSU/DSU, and the CSU/DSU to the line from the telco. • Step 3: If using an internal CSU/DSU, connect the router’s serial interface to the line from the telco. • Step 4: Connect the router’s console port to a PC (using a rollover cable), as needed, to configure the router. • Step 5: Connect a power cable from a power outlet to the power port on the router. • Step 6: Turn on the router.

32. Devices in a SOHO Network with High-Speed CATV Internet

33. Steps for Install a SOHO router • Step 1: Connect a UTP straight-through cable from the router to the switch. • Step 2: Connect a UTP straight-through cable from the router to the cable modem. • Step 3: Connect the router’s console port to a PC (using a rollover cable), as needed, to configure the router. • Step 4: Connect a power cable from a power outlet to the power port on the router. • Step 5: Turn on the router.

34. SOHO Network, Using Cable Internet with an Integrated Device

35. CLI Access

36. Console Connection to a Router

37. Accessing the CLI with Telnet and SSH • To use Telnet, the user must install a Telnet client software package on his or her PC. • Most terminal emulator software packages today include both Telnet and SSH client functions. • The router runs Telnet server software by default, but the router does need to have an IP address configured so that it can send and receive IP packets. • Additionally, the network between the PC and router needs to be up and working so that the PC and router can exchange IP packets.

38. Password Security for CLI Access • By default, a Cisco router is very secure as long as the router is locked inside a room. • By default, a router allows only console access, but no Telnet or SSH access. • From the console, you can gain full access to all router commands, and if so inclined, you can stop all functions of the router. • However, console access requires physical access to the router, so allowing console access for routers just removed from the shipping boxes is reasonable.

39. User and Enable (Privileged) Modes • All three CLI access methods covered so far (console, Telnet, and SSH) place the user in an area of the CLI called user EXEC mode. • User EXEC mode, sometimes also called user mode, allows the user to look around but not break anything. • The “EXEC mode” part of the name refers to the fact that in this mode, when you enter a command, the router executes the command and then displays messages that describe the command’s results. • Cisco IOS supports a more powerful EXEC mode called enable mode (also known as privileged mode or privilegedEXEC mode). • Enable mode is so named because the enable command is used to reach this mode. • Privileged mode earns its name because powerful, or privileged, commands can be executed there. You can use the reload command, which tells the router to reinitialize or reboot Cisco IOS, only from enable mode.

40. User and Privileged Modes

41. CLI Help Features

42. Key Sequences for Command Edit and Recall

43. Configuring Cisco IOS Software • Configuration mode is another mode for the Cisco CLI, similar to user mode and privileged mode. • User mode lets you issue non-disruptive commands and displays some information. • Privileged mode supports a superset of commands compared to user mode, including commands that might harm the router. • However, none of the commands in user or privileged mode changes the router’s configuration. • Configuration mode accepts configuration commands—commands that tell the router the details of what to do, and how to do it.

44. CLI Configuration Mode Versus Exec Modes

45. Configuration Submodes and Contexts • Configuration mode itself contains a multitude of subcommand modes. • Context-setting commands move you from one configuration subcommand mode, or context, to another. • These context-setting commands tell the router the topic about which you will enter the next few configuration commands. • More importantly, the context tells the router the topic you care about right now, so when you use the ? to get help, the router gives you help about that topic only.

46. Storing Router Configuration Files • RAM: Sometimes called DRAM for Dynamic Random-Access Memory, RAM is used by the router just as it is used by any other computer: for working storage. The running (active) configuration file is stored here. • ROM: Read-Only Memory (ROM) stores a bootstrap (or boothelper) program that is loaded when the router first powers on. This bootstrap program then finds the full Cisco IOS image and manages the process of loading Cisco IOS into RAM, at which point Cisco IOS takes over operation of the router. • Flash memory: Either a chip inside the router or a removable memory card, Flash memory stores fully functional Cisco IOS images and is the default location where the router gets its Cisco IOS at boot time. Flash memory also can be used to store any other files, including backup copies of configuration files. • NVRAM: Nonvolatile RAM (NVRAM) stores the initial or startup configuration file that is used when the router is first powered on and when the router is reloaded.

47. Configuration Mode, changes for the running-config file • Step 1: The original hostname command on the router, with the startup-config file matching the running-config file. • Step 2: The hostname command changes the hostname, but only in the running-config file. • Step 3: The show running-config and show startup-config commands are shown, with only the hostname commands displayed for brevity, to make the point that the two configuration files are now different.

48. IFS Filenames for the Startup and Running Config Files

49. Entering the Setup Mode

50. What type of cable is used for console access to a Cisco router and what is the serial communication connection properties? Describe the differences between NVRAM and flash storage Describe the differences between enable mode and configuration mode Describe the differences between startup-config an running-config Check Point