CCNA 1 and 2 Companion Guide, Revised (Cisco Networking Academy Program) part 59 docx

Check Your Understanding 549 13. Which is an IBM-designed WAN data link for Systems Network Architecture (SNA) environments, largely being replaced by the more versatile HDLC? A. Serial Line Interface Protocol B. Point-to-Point Protocol C. Synchronous Data Link Control Protocol D. Simple Data Level Control Protocol 14. Which WAN data link protocol is used for signaling and call setup on an ISDN D channel? A. LAPD B. LAPF C. LAPB D. LAPR 15. Identify the WAN circuit-switched service(s): A. Plain old telephone services (POTS) B. Narrowband ISDN with a maximum bandwidth of 1.544 Mbps C. Narrowband ISDN with a maximum bandwidth of 128 kbps D. Both A and C 16. Which service has become an extremely popular WAN technology in its own right, is more efficient than X.25 but with similar services, has a maximum band- width of 44.736 Mbps, and offers extremely popular 56-Kbps and 384-Kbps implementations in the United States? A. Frame Relay B. X.25 C. POTS D. ATM 17. Identify the cell-switched technology/technologies: A. ATM B. Switched Multimegabit Data Service C. T1 D. Both A and B chpt_10.fm Page 549 Tuesday, May 27, 2003 8:57 AM 550 Chapter 10: WANs and Routers 18. Identify the common type(s) of DSL technology/technologies: A. High-bit-rate DSL (HDSL) B. Single-line DSL (SDSL) C. Asymmetric DSL (ADSL) D. All of the above 19. Which is a family of very high-speed physical layer technologies with a series of data rates available with special designations, implemented at different Optical Carrier (OC) levels ranging from 51.84 Mbps (OC-1) to 9952 Mbps (OC-192), that can achieve these amazing data rates by using wavelength division multi- plexing (WDM)? A. SONET B. HDSL C. ATM D. SMDS 20. Which are the kind of routers that form the primary paths for traffic that is sourced from and destined to other networks? A. Internal routers B. Area Border Routers C. Backbone routers D. Autonomous System (AS) Boundary Routers chpt_10.fm Page 550 Tuesday, May 27, 2003 8:57 AM 550 Chapter 10: WANs and Routers 18. Identify the common type(s) of DSL technology/technologies: A. High-bit-rate DSL (HDSL) B. Single-line DSL (SDSL) C. Asymmetric DSL (ADSL) D. All of the above 19. Which is a family of very high-speed physical layer technologies with a series of data rates available with special designations, implemented at different Optical Carrier (OC) levels ranging from 51.84 Mbps (OC-1) to 9952 Mbps (OC-192), that can achieve these amazing data rates by using wavelength division multi- plexing (WDM)? A. SONET B. HDSL C. ATM D. SMDS 20. Which are the kind of routers that form the primary paths for traffic that is sourced from and destined to other networks? A. Internal routers B. Area Border Routers C. Backbone routers D. Autonomous System (AS) Boundary Routers 1102.book Page 550 Tuesday, May 20, 2003 2:53 PM Objectives Upon completion of this chapter, you will be able to ■ Establish a HyperTerminal session ■ Log into a router ■ Use the help feature in the command-line interface ■ Troubleshoot command errors ■ Understand basic operation of Cisco IOS Software and its features ■ Troubleshoot Cisco IOS Software ■ Use the show version command ■ Understand router user interface and modes 1102.book Page 552 Tuesday, May 20, 2003 2:53 PM Chapter 11 Router Fundamentals In this chapter, you learn how to start a router for the first time by using the correct com- mands and startup sequence to do an initial configuration of the router. This chapter also explains the startup sequence of a router and the setup dialog that the router uses to create an initial configuration file using current versions of Cisco Internetwork Operating System (IOS) Software. Please be sure to look at this chapter’s associated e-Lab Activities, Videos, and PhotoZooms that you will find on the CD-ROM accompanying this book. These CD elements are designed to supplement the material and reinforce the concepts introduced in this chapter. Router Boot Sequence and Setup Mode A router initializes by loading the bootstrap, the operating system, and a configuration file. If the router cannot find a configuration file, it enters setup mode. The router stores a backup copy of the new configuration created from setup mode in nonvolatile random- access memory (NVRAM). When a Cisco router powers up, it performs a power-on self-test (POST). During this self-test, the router performs diagnostics from ROM on all hardware modules. These diagnostics verify the basic operation of the CPU, memory, and network interface ports. After verifying the hardware functions, the router proceeds with software initialization, characterized by the following two processes: ■ System startup routines initiate router software. ■ Fallback routines provide startup alternatives as needed. 1102.book Page 553 Tuesday, May 20, 2003 2:53 PM 554 Chapter 11: Router Fundamentals The goal of the startup routines for Cisco IOS Software is to start the router opera- tions. The router must deliver reliable performance in its job of connecting the user networks that it was configured to serve. To do this, the startup routines must do the following: 1. Make sure that the router hardware is tested and functional. 2. Find and load the Cisco IOS software that the router uses for its operating system. 3. Find and apply the startup configuration file or enter the setup mode. Router Startup Sequence After the POST, the following events occur as the router initializes: 1. The generic bootstrap loader in ROM is carried out. A bootstrap is a simple, pre- set operation that loads instructions. These instructions then cause other instruc- tions to be loaded into memory or cause entry into other configuration modes. 2. The Cisco IOS Software image can be found in several places. The boot field of the configuration register determines the location to be used in loading Cisco IOS Software images. If the boot field indicates a Flash memory or network load, boot system commands in the configuration file indicate the exact name and location of the image. 3. The Cisco IOS Software image is loaded. Then, when Cisco IOS Software is loaded and operational, the operating system locates the hardware and software components and lists the results on the console terminal. 4. The configuration file saved in NVRAM is loaded into main memory and exe- cuted one line at a time. The configuration commands start routing processes, supply addresses for interfaces, set media characteristics, and so on. 5. If no valid configuration file exists in NVRAM, or if NVRAM is erased, the oper- ating system executes a question-driven initial configuration routine referred to as the system configuration dialog, also called the setup dialog when the router is rebooted. Figure 11-1 shows the startup sequence. 1102.book Page 554 Tuesday, May 20, 2003 2:53 PM Router Boot Sequence and Setup Mode 555 Figure 11-1 Startup Sequence System Configuration Dialog Setup is not intended as the mode for entering complex protocol features in the router. The main purpose of setup mode is to quickly install a minimal configuration for any router that cannot find its configuration from another source. For many of the prompts in the system configuration dialog of the setup command facility, default answers appear in square brackets ([ ]) following the question. Press the Enter key to use these defaults. If the system has been previously configured, the defaults that appear will be the cur- rently configured values. To get a fresh start, the command erase startup-config can be used to remove the current configuration file from NVRAM. The reload command reboots the router and initiates setup again. If the system is being configured for the first time, the factory defaults are provided. If there is no factory default, as in the case of passwords, nothing is displayed after the question mark (?). During the setup pro- cess, you can press Ctrl-C at any time to terminate the process and start over. When setup is terminated, all interfaces will administratively are shut down. Example 11-1 shows the setup command. Example 11-1 setup Command # setup System Configuration Dialog At any point you may enter a question mark '?' for help. continues 1102.book Page 555 Tuesday, May 20, 2003 2:53 PM 556 Chapter 11: Router Fundamentals When the configuration process is completed in setup mode, the screen displays the configuration that was created. When you are asked whether to use this configuration, enter yes; the configuration executes and is saved to NVRAM. If you enter no, the con- figuration is not saved and the process begins again. If a More prompt appears, press the spacebar to continue to another screen of information. Setting Up Global Parameters After you view the current interface summary, a prompt appears on your monitor, as shown in Example 11-2, indicating that you must enter the global parameters for your router. These parameters are the configuration values that you select. The first statement indicates that you are configuring the global parameters in the router. The first global parameter enables you to set the router host name. This host name will be part of the Cisco IOS Software prompts for all EXEC modes. At initial configuration, the router name default is displayed between square brackets as [Router]. After you set the router name default, you need to set the various passwords used on the router. Use ctrl-c to abort configuration dialog at any prompt. Default settings are in square brackets '[]'. Basic management setup configures only enough connectivity for management of the system, extended setup will ask you to configure each interface on the system Would you like to enter basic management setup? [yes/no]: no First, would you like to see the current interface summary? [yes]: yes Interface IP-Address OK? Method Status Protocol Ethernet0 198.133.219.1 YES NVRAM up down Serial0 unassigned YES NVRAM administratively down down Serial1 unassigned YES NVRAM administratively down down Example 11-1 setup Command (Continued) 1102.book Page 556 Tuesday, May 20, 2003 2:53 PM Router Boot Sequence and Setup Mode 557 You must enter an enable password. When you enter a string of password characters for the prompt Enter enable secret, the characters are processed by Cisco-proprietary encryption. This enhances the security of the password string. Whenever anyone lists the contents of the router configuration file, this enable password appears as a mean- ingless string of characters. Setup recommends, but does not require, that the enable password be different than the enable secret word. The enable secret word is a one-way cryptographic secret word that is used instead of the enable password, when it exists. The enable password is used when no enable secret word exists. Because of this one-way encryption, the enable secret password cannot be recovered if forgotten, whereas the enable password is clear text and can be read from the config file. The enable password also is used with other versions of Cisco IOS Software. All pass- words are case sensitive and can be alphanumeric. It is possible to secure the router by using passwords to restrict access to individual lines as well. Example 11-3 uses the line-console 0 command followed by the login and password subcommands to establish a login password for the console terminal. The purpose here is to establish the need for a user to log into the console before gaining Example 11-2 Global Parameters Configuring global parameters: Enter host name [Router]: Cisco The enable secret is a password used to protect access to privileged EXEC and configuration modes. This password, after entered, becomes encrypted in the configuration. Enter enable secret: cougars The enable password is used when you do not specify an enable secret password, with some older software versions, and some boot images. Enter enable password: lumberjacks The virtual terminal password is used to protect access to the router over a network interface. Enter virtual terminal password: matadors Configure SNMP Network Management? [yes]: no 1102.book Page 557 Tuesday, May 20, 2003 2:53 PM 558 Chapter 11: Router Fundamentals access to the router. console 0 designates the router’s console connection, and login prompts the user for a password before allowing console connectivity. As demonstrated in Example 11-4, the line vty 0 4 command followed by the pass- word subcommand establishes a login password on incoming Telnet sessions. After you enter the passwords for the various ports, the router asks you to enter the routing protocols that are to be used, as shown in Example 11-5. When you are prompted for parameters for each protocol, use the configuration values that you have selected for your router. Whenever you answer yes to a prompt, additional questions might appear regarding the protocol. Example 11-3 Configuring the Router’s Console Password Router(config)# line console 0 Router(config-line)# login Router(config-line)# password cisco Example 11-4 Configuring the Router’s Virtual Terminal Password Router(config)# line vty 0 4 Router(config-line)# password sanjose Example 11-5 Prompts for Global Parameters at the Console Configure IP? [yes]: Configure IGRP routing? [yes]: 200 % Please answer 'yes' or 'no'. Configure IGRP routing? [yes]: yes Your IGRP autonomous system number [1]: 200 Configuring interface parameters: Do you want to configure Ethernet0 interface? [yes]: yes Configure IP on this interface? [yes]: yes IP address for this interface: 10.10.10.1 Subnet mask for this interface [255.0.0.0] : Class A network is 10.0.0.0, 8 subnet bits; mask is /8 Do you want to configure Serial0 interface? [yes]: n 1102.book Page 558 Tuesday, May 20, 2003 2:53 PM . the router is rebooted. Figure 11 -1 shows the startup sequence. 11 02. book Page 554 Tuesday, May 20 , 20 03 2: 53 PM Router Boot Sequence and Setup Mode 555 Figure 11 -1 Startup Sequence System Configuration. Protocol Ethernet0 19 8 .13 3. 21 9 .1 YES NVRAM up down Serial0 unassigned YES NVRAM administratively down down Serial1 unassigned YES NVRAM administratively down down Example 11 -1 setup Command (Continued) 11 02. book. Software ■ Use the show version command ■ Understand router user interface and modes 11 02. book Page 5 52 Tuesday, May 20 , 20 03 2: 53 PM Chapter 11 Router Fundamentals In this chapter, you learn