Router Components & Configuration Purpose: This chapter reviews general networking theory and introduces students to some of Cisco’s product line. Timing: This chapter takes approximately 1.5 hours to present. Note: This section has a product selection tool laboratory exercise at the end. Contents: Objectives—This section explains what the student will be able to do at the end of this chapter. Defining Network Components—This section displays where devices are placed in the network. Mapping Business Needs to a Hierarchical Model—This section describes the heirarchical model used in network design. OSI Model Overview—This section reviews the OSI model. Communicating Between Layers—This section describes encapsulation and de-encapsulation. Written Exercise 1—This section has a written exercise to test the students’ knowledge of the OSI model. Physical Layer Functions—This section describes the physical layer of the OSI Model. Data Link Layer Functions—This section describes the data link layer of the OSI Model. Network Layer Functions—This section describes the network layer of the OSI Model. Transport Layer Functions—This section describes the transport layer of the OSI Model.

Router Components & Configurations Topics Physical components Memory components Configuration modes Keystroke shortcuts Configuring router name, passwords and interfaces Router boot sequence Managing the router IOS and configuration

Router Components Ports Interfaces Memory

Router Ports Console port Aux port – Where you connect from your computer to directly configure the router or switch. Use rollover cable & DB9 connector Aux port – for modem access

Setting up a Console Connection Device with console PCs require an RJ-45 to DB-9 or RJ-45 to DB-25 adapter COM port settings are 9600 bps, 8 data bits, no parity, 1 stop bit, no flow control This provides out-of-band console access AUX switch port may be used for modem-connected console Emphasize: Rollover cables are not the same as crossover cables. The pinouts for a rollover cable are 1-8, 2-7, 3-6, 4-5, 5-4, 6-3, and so on. Students must also set up a HyperTerminal console session if they are on a Microsoft Windows ‘95 platform. The instructions to establish a console session using HyperTerminal are in the HyperTerminal appendix.

Router Interfaces Ethernet Serial Ethernet is 10 mbps Fast Ethernet is 100 mbps (unless auto senses 10 mbps) Serial Speed determined by clocking across link Uses various cables and connectors.

Router Memory Components NVRAM RAM Config register Slide 1 of 1 Purpose: Emphasize: Note: RAM - Packet buffers, running configurations, running IOS ROM - POST, Rom Monitor, Baby IOS (Rxboot) NVRAM - Backup configurations, Config register Flash - IOS Flash memory is non-volatile. It behaves like a file system. It is more expensive than NVRAM. It is readable and writeable. The 2500 routers run from flash. If it is running IOS from flash, then the flash is in the readable state. Use the boot system command to boot an IOS from a tftp server so the 2500 can run from RAM if you need to write or erase flash online. Flash ROM

Random Access Memory (RAM) Stores operating system during operation Stores running configuration Buffers for packets Routing table Other tables as needed

Non-volatile RAM (NVRAM) Stores startup configuration Battery backed-up

Flash Holds IOS permanently On switches also holds VLAN database Can be used as a file system

Read-Only Memory (ROM) POST Bootstrap Baby IOS ROMMON (ROM monitor)

Router Power on and Bootup Sequence Power on self test (POST) Load and run bootstrap code Find the IOS software Load the IOS software Find the configuration Load the configuration Run Slide 1 of 1 Purpose: Emphasize: In a later slide, there is a very detailed flowchart of the router startup process.

Finding the IOS Order of search: 1. Check configuration register show startup-config NVRAM Config register show version Console Flash Order of search: 1. Check configuration register 2. Parse config in NVRAM 3. Default to first file in Flash 4. Attempt net boot 5. RXBOOT 6. ROMMON IOS Slide 1 of 1 Purpose: Emphasize: Note: There is a detail flowchart of the router startup process on the next slide.

Determining the Current Configuration Register Value wg_ro_a#show version Cisco Internetwork Operating System Software IOS (tm) 2500 Software (C2500-JS-L), Version 12.0(3), RELEASE SOFTWARE (fc1) Copyright (c) 1986-1999 by cisco Systems, Inc. Compiled Mon 08-Feb-99 18:18 by phanguye Image text-base: 0x03050C84, data-base: 0x00001000 ROM: System Bootstrap, Version 11.0(10c), SOFTWARE BOOTFLASH: 3000 Bootstrap Software (IGS-BOOT-R), Version 11.0(10c), RELEASE SOFTWARE (fc1) wg_ro_a uptime is 20 minutes System restarted by reload System image file is "flash:c2500-js-l_120-3.bin" --More-- Configuration register is 0x2102 Slide 1 of 1 Purpose: Emphasize: Use the show version command to display the value of the Config register setting. When you change the config register, we will see from the show version output: Configuration register is 0x2102 (will be 0x2142 at next reload). The new config register value will be used at the next reload. Configuration register value in show version

Configuration Register Values Router#configure terminal Router(config)#config-register 0x2102 [Ctrl-Z] Router#reload Configuration register bits 3, 2, 1, and 0 set boot option Slide 1 of 4 Purpose: This slide shows how to use the config-register command to set the boot field. Emphasize: Layer 1—Shows the example of the config-register command. It assumes the network administrator will set the register to the default setting of 0x2102. (0x means the number is in hex). In this course, limit the focus to the boot field that is formed by bits 3, 2, 1 and 0.

Configuration Register Values Router#configure terminal Router(config)#config-register 0x2102 [Ctrl-Z] Router#reload Configuration register bits 3, 2, 1, and 0 set boot option Configuration Register Boot Field Value Meaning Use ROM monitor mode (Manually boot using the b command) Slide 2 of 4 Purpose: Emphasize: Layer 2—Adds the table that identifies the boot field Configuration Register values and meanings. The first value, 0x0, enters ROM monitor mode. Your students should not enter this mode except for password recovery. Refer students to the Doc CD Rom or the “Installation and Maintenance of Cisco Routers (IMCR)” hardware course for more details. 0x0

Configuration Register Values Router#configure terminal Router(config)#config-register 0x2102 [Ctrl-Z] Router#reload Configuration register bits 3, 2, 1, and 0 set boot option Configuration Register Boot Field Value Meaning Use ROM monitor mode (Manually boot using the b command) Slide 3 of 4 Purpose: Emphasize: Layer 3—Adds the second boot field value 0x1. This setting automatically boots the system from ROM and provides a subset of the Cisco IOS image (Rxboot mode). Routing is not enabled in the Rxboot mode. However, the router has IP functionality in the Rxboot mode. For example, from the Rxboot mode, the router can perform a tftp transfers to copy an IOS image from a tftp server to its flash memory. Some routers can store a full IOS image in ROM. 0x0 Automatically boot from ROM (Provides IOS subset) 0x1

Configuration Register Values Router#configure terminal Router(config)#config-register 0x2102 [Ctrl-Z] Router#reload Configuration register bits 3, 2, 1, and 0 set boot option Check configuration register value with show version Configuration Register Boot Field Value Meaning Use ROM monitor mode (Manually boot using the b command) Slide 4 of 4 Purpose: Emphasize: Layer 4—Finishes with the third case, a boot field setting in the range of 0x2 to 0xF. The entry of a Configuration Register value in the 0x2 to 0xF range is significant. When the router attempts to boot from the net (Netboot), the bootstrap program generates an IOS filename based on the value of the boot field. For example, with the setting 0x2, the default IOS filename generated will be cisco2-xxxx, where xxxx refers to a processor name (for example, 2500). Again, refer students to the IMCR course for details. You use the config-register command to change the value. Notice that the bottom lines of the show version output indicates what the value the config register will be on the next reload. 0x0 Automatically boot from ROM (Provides IOS subset) 0x1 Examine NVRAM for boot system commands (0x2 default if router has Flash) 0x2 to 0xF

Loading the IOS from Flash RAM IOS Flash Console Slide 1 of 1 Purpose: Emphasize: Note: The 2500 series routers do not operate this way. The 2500 series routers normally run IOS from flash. The IOS in flash is not compressed but it is relocatable. Relocatable means the IOS image can be ran from flash or from RAM. The 2500 can run from RAM if you use the “boot system tftp” command to boot the IOS image. The Rxboot mode is also ran from RAM on the 2500 routers. IOS show flash Flash file is decompressed into RAM

show flash Command wg_ro_a#sh flash System flash directory: File Length Name/status 1 10084696 c2500-js-l_120-3.bin [10084760 bytes used, 6692456 available, 16777216 total] 16384K bytes of processor board System flash (Read ONLY) Slide 1 of 1 Purpose: Emphasize: Note: The current state of the flash memory is in Read ONLY mode. It is running IOS from flash. This router has a total of 16MB of flash memory. The flash contains one IOS image and there are 6.69MB available space left in flash.

Loading the Configuration RAM NVRAM Config Config IOS show running-config show startup-config Console Slide 1 of 1 Purpose: Emphasize: Using the default config register value (0x2102), the router will load the config from NVRAM at startup. Setup utility Load and execute config from NVRAM If no config in NVRAM, enter setup mode

show running and show startup Commands In RAM In NVRAM wg_ro_c#show running-config Building configuration... Current configuration: ! version 12.0 ! -- More -- wg_ro_c#show startup-config Using 1359 out of 32762 bytes ! version 12.0 -- More -- Slide 1 of 1 Purpose: This slide is a repeated slide from chapter 4. Emphasize: Display current and saved configuration

Sources of Configurations RAM NVRAM copy running startup Config Config copy startup running (merge) Slide 1 of 4 Purpose: Emphasize: When copying to RAM, it is always a merge not an overwrite. Explain on the board the difference between a merge versus an overwrite. Explain the general syntax of the copy command: copy <from> <to> With 12.0, the copy command supports a new syntax. The new syntax is explained in a later slide. NVRAM

Sources of Configurations RAM NVRAM copy running startup Config Config copy startup running (merge) config term (merge) Slide 2 of 4 Purpose: Emphasize: NVRAM Terminal

Sources of Configurations copy startup running (merge) RAM NVRAM copy running startup Config Config copy startup running (merge) config term (merge) copy tftp run (merge) Console Slide 3 of 4 Purpose: Emphasize: Note: The Cisco TFTP server software which runs on Windows 95/98/NT can be downloaded from the url listed below: http://www.cisco.com/cgi-bin/tablebuild.pl/tftp A Cisco router can also be configured to be a tftp server using the “tftp-server” global configuration command. copy tftp start copy run tftp NVRAM Terminal TFTP server copy start tftp TFTP server

Sources of Configurations RAM NVRAM copy running startup Config Config copy startup running (merge) config term (merge) erase start copy tftp run (merge) Console Slide 4 of 4 Purpose: Emphasize: copy tftp start Blank 000000 NVRAM Terminal TFTP server Erase Start copy run tftp copy start tftp TFTP server

copy run tftp and copy tftp run Commands wg_ro_a#copy running-config tftp Address or name of remote host []? 10.1.1.1 Destination filename [running-config]? wgroa.cfg .!! 1684 bytes copied in 13.300 secs (129 bytes/sec) wg_ro_a#copy tftp running-config Source filename []? wgroa.cfg Destination filename [running-config]? Accessing tftp://10.1.1.1/wgroa.cfg... Loading wgroa.cfg from 10.1.1.1 (via Ethernet0): ! [OK - 1684/3072 bytes] 1684 bytes copied in 17.692 secs (99 bytes/sec) Slide 1 of 1 Purpose: Emphasize: Note: Release 12.0 supports new syntax for the “copy” command.

Cisco IOS File Systems and Devices RAM NVRAM system: nvram: Slide 1 of 1 Purpose: Emphasize: In release 12.0, there are new copy commands. These new commands treat the RAM, Flash, NVRAM, tftp, ftp, etc… as a file system. Since at the time when this class was developed, the most common IOS in the field is pre 12.0, these 12.0 commands are not covered in detail in this class. Flash TFTP server flash: tftp:

Managing IOS Images Network server Router Network server c2500-js-l_120-3.bin Network server Router Slide 1 of 1 Purpose: Emphasize: This section introduces topics on managing your configuration file and IOS image. FLASH Network server

Preparing for a Network Backup Image Network server Router Check access to the server Slide 1 of 4 Purpose: This slide establishes an overview and reason to use the TFTP server as a load source or backup destination for Cisco IOS software. It then presents the preparation details needed before executing TFTP copies. Emphasize: Geographically distributed routers need a source or backup location for software images. Using a network server allows image and configuration uploads and downloads over the network. The network server can be another router, a workstation, or a host system. A router can be configured as a tftp server using the tftp-server global configuration command. Layer one - First, you need to check that you have access to the network server. Example, use the ping command to see if you can reach the server.

Preparing for a Network Backup Image Network server Router Check access to the server Check space available on the server Slide 2 of 4 Purpose: Emphasize: Layer 2 — you need to check that you have enough disk space on the tftp server to house the new system image. On the router, use the show flash command to determine the length of the IOS image.

Preparing for a Network Backup Image c2500-js-l_120-3.bin Network server Router Check access to the server Check space available on the server Check file naming convention Slide 2 of 4 Purpose: Emphasize: Layer 3 — you need to check the naming conventions required on the server. Example, what is the max number of characters allowed in the filename by the server’s O.S? What is the max number of characters allowed in the filename extension by the server’s O.S?

Preparing for a Network Backup Image c2500-js-l_120-3.bin Network server Router Check access to the server Check space available on the server Check file naming convention Create file on server if required Slide 4 of 4 Purpose: Emphasize: Layer 4—On some Unix server, you may have to first create the file first before you can download the IOS image from the router to the tftp server. You can use the “touch” Unix command to create an empty file on the Unix server.

Verifying Memory and Deciphering Image Filenames wg_ro_a#show flash System flash directory: File Length Name/status 1 10084696 c2500-js-l_120-3.bin [10084760 bytes used, 6692456 available, 16777216 total] 16384K bytes of processor board System flash (Read ONLY) Verify Flash memory has room for the IOS image Slide 1 of 1 Purpose: Emphasize: The show flash command is an important tool to use to gather information about your router memory and image file. Caution students that they must know that they are loading the correct and appropriate image. The name for the Cisco IOS image file contains multiple parts, each with a specific meaning: The first part of the image name contains the platform on which the image runs. In this example, the platform is C2500. The second part of the name identifies the special capabilities of the image file. A letter or series of letters identifies the feature sets supported in that image. In this example, the j indicates this is an enterprise image, and the s indicates it contains extended capabilities. The third part of the name specifies where the image runs and if the file is compressed. In this example, l indicates the file is relocatable and not compressed. Relocatable means the IOS can be ran from flash or from RAM. You should be careful in reading the Cisco IOS image filename. Some fonts display the lowercase letter “l” and the number 1 as the same character. How you type the characters will impact the ability of the router to load the files correctly. The fourth part of the name indicates the version number. In this example, the version number is 12.0 (3). The final part of the name is the file extension. The .bin extension indicates this file is a binary executable file. The Cisco IOS software naming conventions, name part field meaning, image content, and other details are subject to change. Refer to Cisco Connection Online (CCO) for updated details.

Creating a Software Image Backup FLASH Network server copy flash tftp wg_ro_a#copy flash tftp Source filename []? c2500-js-l_120-3.bin Address or name of remote host []? 10.1.1.1 Destination filename [c2500-js-l_120-3.bin]? !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! <output omitted> 10084696 bytes copied in 709.228 secs (14223 bytes/sec) wg_ro_a# Slide 1 of 1 Purpose: This slide discusses how to create a backup version of a Cisco IOS software image to a tftp server. Emphasize: Routers by default comes with Flash memory that have a preloaded copy of the Cisco IOS software. Although Flash is extremely reliable—good for 65 years and 100,000 rewrites—it is a good idea to make a backup copy of the Cisco IOS software if you have a tftp server available. If you had to replace Flash memory for some reason, you would have a backup copy at the revision level currently running on your network. The copy command screen output varies depending on the Cisco IOS software level. Determine the platform type of your tftp server prior to beginning the backup procedure. The tftp server may be running Windows, UNIX, Mac or other O.S . Filename and directory access procedures may vary depending on the tftp server platform and platform version. Back up current files prior to updating Flash

Upgrading the Image from the Net FLASH Network server wg_ro_a#copy tftp flash Address or name of remote host [10.1.1.1]? Source filename []? c2500-js-l_120-3.bin Destination filename [c2500-js-l_120-3.bin]? Accessing tftp://10.1.1.1/c2500-js-l_120-3.bin... Erase flash: before copying? [confirm] Erasing the flash filesystem will remove all files! Continue? [confirm] Erasing device... eeeee (output omitted) ...erased Erase of flash: complete Loading c2500-js-l_120-3.bin from 10.1.1.1 (via Ethernet0): !!!!!!!!!!!!!!!!!!!! (output omitted) [OK - 10084696/20168704 bytes] Verifying checksum... OK (0x9AA0) 10084696 bytes copied in 309.108 secs (32636 bytes/sec) wg_ro_a# Slide 1 of 1 Purpose: This slide describes how to load a backup version of a Cisco IOS software image from a tftp server to the router. Emphasize: If you need more flash space to load a copy of the Cisco IOS software, then you must first erase the Flash memory. You cannot erase a single image—you must erase all copies of Cisco IOS software from Flash. However, if Flash memory on the router is partitioned, you can erase one or more of the parts. After the tftp transfer is completed, use the show flash command to view the file size to compare its size with that of the original on the server. If the IOS is running from flash, then the flash is in the read only state. To change the flash to a writeable state: you can use the boot system tftp command to boot an IOS from a tftp server and the IOS will be ran from RAM or you can go to the Rxboot mode to perform the copy. Erase Flash occurs before loading new image Note message that image already exists

Cisco IOS User Interface Overview The CLI is used to enter commands. Operations vary between routers and switches, but both use the same CLI. Users may type or paste entries within the console configuration modes. Configuration modes have distinctive prompts. Two primary EXEC modes are user mode and privileged mode. Changes are not saved automatically. Purpose: This slide introduces the two Cisco IOS EXEC modes on the Catalyst 1900 switch and routers. Emphasize: As you present this, describe the bullet points that can prepare your students to work with the Cisco IOS user interface.

Overview of Cisco IOS Configuration Modes Emphasize: Here is a list of some of the configuration modes available. For a complete list of the router configuration modes, refer to the Cisco Documentation CD-ROM.

Help Facilities of the Cisco IOS CLI Purpose: This slide describes the Help facilities on the Catalyst 1900 switch. Emphasize: After showing how to log in to the Catalyst 1900 Cisco IOS CLI and enabled EXEC privileged mode, use this slide to present the three main types of command-line help available. This list is similar to, but not as extensive as the types of command-line help on the router that you present later with a similar slide. If at this point you can demonstrate what you are presenting, so much the better. The help on the switch is very similar to the help on the router, so the details are only presented once, in the router section.