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This chapter describes how to load system images, microcode images, and configuration files. The system images contain the system software, and the configuration files contain commands entered to customize the function of the router. Microcode images contain microcode to be downloaded to various hardware devices. The instructions in this chapter describe how to copy system images from routers to network servers (and vice versa), display and compare different configuration files, and list the system software version running on the router.
This chapter also describes the AutoInstall procedure, which you can use to automatically configure and enable a new router upon startup.
For a complete description of the commands mentioned in this chapter, refer to the "System Image, Microcode Image, and Configuration File Load Commands" chapter in the Router Products Command Reference publication.
Note You also can use the setup command and its interactive prompts to create a basic configuration file. See the Router Products Getting Started Guide for more information.
With Cisco IOS Release 10.3(3), you can use Flash memory cards in the Personal Computer Memory Card International Association (PCMCIA) Flash memory card slots on your Cisco 7500 series. The Cisco 7500 series Route Switch Processor (RSP) card contains two PCMCIA slots.
These Flash memory cards can store executable images and configuration files. The router can now boot images and load configuration files from Flash memory cards as well as from internal flash (or "bootflash" on the Cisco 7500 series), NVRAM, and the network.
Because the Cisco 7500 series can boot images and load configuration files from several locations, it uses special ROM monitor environment variables to specify the location and filename of images and configuration files that the router is to use for various functions. These special environment variables are as follows:
The BOOT environment variable specifies a list of bootable images on various devices. For the Cisco 7500 series, valid devices are internal flash (bootflash:), the first PCMCIA slot (slot0:), the second PCMCIA slot (slot1:), and tftp. Once you save the BOOT environment variable to your startup configuration, the router checks the variable upon startup to determine the device and filename of the image to boot.
The router tries to boot the first image in the BOOT environment variable list. If the router is unsuccessful at booting that image, it tries to boot the next image specified in the list. The router tries each image in the list until it successfully boots. If the router cannot boot any image in the BOOT environment variable list, then the router attempts to boot the rxboot image of the Cisco 7500 series.
If an entry in the BOOT environment variable list does not specify a device, the router assumes the device is tftp. If an entry in the BOOT environment variable list specifies an invalid device, the router skips that entry.
The BOOTLDR environment specifies the flash device and filename containing the rxboot image that the ROM monitor uses. For the Cisco 7500 series, valid devices are bootflash:, slot0:, and slot1:.
This environment variable allows you to have several rxboot images. Moreover, you can instruct the ROM monitor to use a specific rxboot image without having to switch out ROMs. Once you save the BOOTLDR environment variable to your startup configuration, the router checks the variable upon startup to determine which rxboot image to use.
The CONFIG_FILE environment variable specifies the device and filename of the configuration file to use for initialization (startup). For the Cisco 7500 series, valid devices are bootflash:, nvram:, slot0:, and slot1:. Once you save the CONFIG_FILE environment variable to your startup configuration, the router checks the variable upon startup to determine the location and filename of the configuration file to use for initialization.
The router uses the NVRAM configuration during initialization when the CONFIG_FILE environment variable does not exist or when it is null (such as at first-time startup). If the router detects a problem with NVRAM or the configuration it contains, the router enters setup mode. Refer to the Router Products Getting Started Guide for more information on the setup command facility.
Although the ROM monitor controls environment variables, you can create, modify, or view them with certain system image commands. To create or modify the BOOT, BOOTLDR, and CONFIG_FILE environment variables, use the boot system, boot bootldr, and boot config system image commands, respectively.
Note When you use these three global configuration commands, you affect only the running configuration. You must save the environment variable settings to your startup configuration to place the information under ROM monitor control and for the environment variables to function as expected. Use the copy running-config startup-config or write memory command to save the environment variables from your running configuration to your startup configuration.
You can view the contents of the BOOT, BOOTLDR, and the CONFIG_FILE environment variables by issuing the show boot command. This command displays the settings for these variables as they exist in the startup configuration as well as in the running configuration if a running configuration setting differs from a startup configuration setting.
Use the show configuration command to display the contents of the configuration file pointed to by the CONFIG_FILE environment variable.
For complete information on the commands presented in this section, refer to the Router Products Command Reference publication.
One of the first attempts to use the network as a resource in the UNIX community resulted in the design and implementation of the remote shell protocol, which included remote shell (rsh) and remote copy (rcp). Rsh and rcp give users the ability to execute commands remotely and copy files to and from a file system residing on a remote host or server on the network. Cisco's implementation of rsh and rcp will interoperate with standard implementations of rsh and rcp.
From the router, you can use rsh to execute commands on remote systems to which you have access. When you issue the rsh command, a shell is started on the remote system. The shell allows you to execute commands on the remote system without having to log into the target host.
In other words, you do not need to connect to the system or router and then disconnect after you execute a command if you use rsh. For example, you can use rsh to remotely look at the status of other routers without connecting to the target router, executing the command, and then disconnecting from the router. This is useful for looking at statistics on many different routers.
To gain access to a remote system running rsh, such as a UNIX host, there must be an entry in the system's .rhosts file or its equivalent identifying you as a trusted user who is authorized to execute commands remotely on the system. On UNIX systems, the .rhosts file identifies trusted users who can remotely execute commands on the system.
You can enable rsh support on a Cisco router to allow users on remote systems to execute commands on the router. However, our implementation of rsh does not support an .rhosts file. Instead, you configure a local authentication database to control access to the router by users attempting to execute commands remotely using rsh. A local authentication database is similar in concept and use to a UNIX .rhosts file. Each entry that you configure in the authentication database identifies the local user, the remote host, and the remote user.
The rcp copy commands rely on the rsh server (or daemon) on the remote system. To copy files using rcp, you do not need to create a server for file distribution, as you do with TFTP.You only need to have access to a server that supports rsh. (Most UNIX systems support rsh.) Because you are copying a file from one place to another, you must have read permission on the source file and write permission on the destination file. If the destination file does not exist, rcp creates it for you.
Although our rcp implementation emulates the behavior of the UNIX rcp implementation—copying files among systems on the network—our command syntax differs from the UNIX rcp command syntax. Our rcp support offers a set of copy commands that use rcp as the transport mechanism. These rcp copy commands are similar in style to our TFTP copy commands, but they offer an alternative that provides faster performance and reliable delivery of data. This is because the rcp transport mechanism is built on and uses the Transmission Control Protocol/Internet Protocol (TCP/IP) stack, which is connection oriented. You can use rcp commands to copy system images and configuration files from the router to a network server and vice versa.
You can also enable rcp support on the router to allow users on remote systems to copy files to and from the router.
You can perform the tasks in the following sections to load system images, microcode images, and configuration files.
This section provides information about AutoInstall, a procedure that allows you to configure a new router automatically and dynamically. The AutoInstall procedure involves connecting a new router to a network on which there is an existing preconfigured router, turning on the new router, and enabling it with a configuration file that is automatically downloaded from a Trivial File Transfer Protocol (TFTP) server.
The following sections provide the requirements for AutoInstall and an overview of how the procedure works. To start the procedure, go to "Perform the AutoInstall Procedure" later in this section.
For the AutoInstall procedure to work, your system must meet the following requirements:
Note Only Token Ring interfaces that set ring speed with physical jumpers will support AutoInstall. AutoInstall does not work with Token Ring interfaces for which the ring speed must be set using software configuration commands. If the ring speed is not set, the interface is set to shutdown mode.
frame-relay map ip 172.21.177.100 100 dlci
AutoInstall over Frame Relay and over other WAN encapsulations support downloading configuration files from UNIX-based and DOS-based TFTP servers. Other booting mechanisms such as RARP and SLARP also support UNIX-based and DOS-based TFTP servers.
The DOS format of the UNIX network-confg file that must reside on the server must be eight characters or less, with a three-letter extension. Therefore, when an attempt to load network-confg fails, AutoInstall automatically attempts to download cisconet.cfg from the TFTP server.
If cisconet.cfg exists and a download succeeds, then the server is assumed to be a DOS machine. The AutoInstall program will then attempt to resolve the host name for the router through host commands in cisconet.cfg.
If cisconet.cfg does not exist or cannot be downloaded, or the program is unable to resolve a host name, DNS will attempt to resolve the host name of the router. If it is unable to resolve the host name through DNS, the router will attempt to download ciscortr.cfg. If the host name is longer than eight characters, it will get truncated to eight characters. For example, a router with a host name "australia" will be treated as "australi" and an attempt will be made to download australi.cfg.
The format of cisconet.cfg and ciscortr.cfg are to be the same as those described for network-confg and hostname-confg.
If neither network-confg nor cisconet.cfg exist and DNS is unable to resolve the host name, the program will attempt to load router-confg, and then ciscortr.cfg if router-confg does not exist or cannot be downloaded. The cycle is repeated three times.
Once the requirements for using AutoInstall are met, the dynamic configuration of the new router occurs in the following order:
1. The new router acquires its IP address. Depending upon the interface connection between the two routers, the new router's IP address is dynamically resolved by either SLARP requests or BOOTP or RARP requests.
2. The new router resolves its name either through network-confg or cisconet.cfg or through DNS.
3. The new router automatically requests and downloads its configuration file from a TFTP server.
4. If a host name is not resolved, the newrouter will attempt to load router-confg or ciscortr.cfg.
The new router (newrouter) resolves its interface's IP addresses by one of the following means:
The existing router (existing) responds in one of the following ways depending upon the request type:
A BOOTP or RARP server must have already been set up to map newrouter's MAC address to its IP address. If the BOOTP server does not reside on the directly attached network segment, routers between newrouter and the BOOTP server can be configured using the ip helper-address command to allow the request and response to be forwarded between segments, as shown in Figure 3-2.
AutoInstall over Frame Relay is a special case in which BOOTP is used but the existing router acts as a BOOTP server and responds to the incoming BOOTP request. Only a helper address and a Frame Relay map need to be set up. There is no need for a MAC-to-IP address map on the existing router.
As of Software Release 9.21, routers can be configured to act as RARP servers.
As soon as one interface resolves its IP address, the router will attempt to resolve its host name. Therefore, only one IP address needs to be set up using SLARP, BOOTP, or RARP.
The new router resolves its IP address-to-host name mapping by sending a TFTP broadcast requesting the file network-confg, as shown in Figure 3-3.
The network-confg file is a configuration file generally shared by several routers. In this case, it is used to map the IP address of the new router just obtained dynamically to the name of the new router. The file network-confg must reside on a reachable TFTP server and must be globally readable.
The following is an example of a minimal network-confg file that maps the IP address of the new router (131.108.10.2) to the name newrouter. The address of the new router was learned via SLARP and is based on existing's IP address of 131.108.10.1.
If you are not using AutoInstall over Frame Relay, the host portion of the address must be 1 or 2. AutoInstall over Frame Relay does not have this addressing constraint.
If newrouter does not receive a network-confg file, or if the IP address-to-host-name mapping does not match the newly acquired IP address, newrouter sends a DNS broadcast. If DNS is configured and has an entry that maps newrouter's SLARP, BOOTP, or RARP-acquired IP address to its name, newrouter successfully resolves its name.
If DNS does not have an entry that maps the new router's SLARP, BOOTP, or RARP-acquired address to its name, the new router cannot resolve its host name. The new router attempts to download a default configuration file as described in the next section, and failing that, enters setup mode (except with AutoInstall over Frame Relay, in which case the router enters user EXEC mode).
After the router successfully resolves its host name, newrouter sends a TFTP broadcast requesting the file newrouter-confg. The name newrouter-confg must be in all lowercase, even if the true host name is not. If newrouter cannot resolve its host name, it sends a TFTP broadcast requesting the default host configuration file router-confg. The file is downloaded to newrouter, where the configuration commands take effect immediately.
When using AutoInstall over Frame Relay, you are put into setup mode while the AutoInstall process is running. If the configuration file is successfully installed, the setup process is terminated. If you expect the AutoInstall process to be successful, either do not respond to the setup prompts or respond to the prompts as follows:
If you do not expect the AutoInstall process to be successful, create a configuration file by responding to the setup prompts. The AutoInstall process is terminated transparently.
You will see the following display as the AutoInstall operation is in progress:
If the host configuration file contains only the minimal information, you must Telnet into existing, from there Telnet to newrouter, and then run the setup command to configure newrouter. Refer to the Router Products Getting Started Guide for details on the setup command.
If the host configuration file is complete, newrouter should be fully operational. You can enter the enable command (with the system administrator password) at the system prompt on newrouter, and then issue the write memory command to save the information in the recently obtained configuration file into nonvolatile random-access memory (NVRAM) or the location specified by the CONFIG_FILE environment variable. If a reload occurs, newrouter simply loads its configuration file from NVRAM.
If the TFTP request fails, or if newrouter still has not obtained the IP addresses of all its interfaces, and those addresses are not contained in the host configuration file, then newrouter enters setup mode automatically. Setup mode prompts for manual configuration of the router via the console. The new router continues to issue broadcasts to attempt to learn its host name and obtain any unresolved interface addresses. The broadcast frequency will dwindle to every ten minutes after several attempts. Refer to the Router Products Getting Started Guide for details on the setup command.
To dynamically configure a new router using AutoInstall, complete the following tasks. Steps 1, 2, and 3 are completed by the central administrator. Step 4 is completed by the person at the remote site.
Step 2 Set up the TFTP server to support the AutoInstall procedure.
Step 3 Set up the BOOTP or RARP server if needed. A BOOTP or RARP server is required for AutoInstall using an Ethernet, Token Ring, FDDI, or Frame Relay-encapsulated serial interface. With a Frame Relay-encapsulated serial interface, the existing router acts as the BOOTP server. A BOOTP or RARP server is not required for AutoInstall using an HDLC-encapsulated serial interface.
Step 4 Connect the new router to the network.
You can use any of the following types of interface:
To set up AutoInstall via a serial line with HDLC encapsulation (the default), you must configure the existing router. Perform the following steps, beginning in global configuration mode:
| 1This command and the clock rate command are documented in the "Interface Commands" chapter in the Router Products Command Reference publication.
2This command and the ip helper-address command are documented in the "IP Commands" chapter in the Router Products Command Reference publication. |
In the following example, the existing router's configuration file contains the commands needed to configure the router for AutoInstall on a serial line using HDLC encapsulation:
To set up AutoInstall using an Ethernet, Token Ring, or FDDI interface, you must modify the configuration of the existing router. Perform the following steps, beginning in global configuration mode.
| 1This command is documented in the "Interface Commands" chapter in the Router Products Command Reference publication.
2This command and the ip helper-address command are documented in the "IP Commands" chapter in the Router Products Command Reference publication. |
Typically, the LAN interface and IP address are already configured on the existing router. You might need to configure an IP helper address if the TFTP server is not on the same network as the new router.
In the following example, the existing router's configuration file contains the commands needed to configure the router for AutoInstall on an Ethernet interface:
To set up AutoInstall via a serial line with Frame Relay encapsulation, you must configure the existing router. Perform the following tasks, beginning in global configuration mode:
| Task | Command |
|---|---|
| Step 1. Configure the serial interface that connects to the new router and enter interface configuration mode. | |
| Step 2. Configure Frame Relay encapsulation on the interface that connects to the new router. | |
| Step 3. Create a Frame Relay map pointing back to the new router.
For point-to-point subinterfaces, assign a data link connection identifier (DLCI) to the interface that connects to the new router, and provide the IP address of the serial port on the new router. |
frame-relay map ip ip-address dlci2 frame-relay interface-dlci dlci option [protocol ip ip-address]2 |
| Step 4. Enter an IP address for the interface. This step sets the IP address of the existing router. | |
| Step 5. Configure a helper address for the TFTP server. | |
| Step 6. Optionally, configure a DCE clock rate for the serial line, unless an external clock is being used. This step is needed only for DCE appliques. | |
| Step 7. Exit configuration mode. | |
| Step 8. Save the configuration changes to your startup configuration. On most platforms, this step saves the configuration to NVRAM. On the Cisco 7500 series, this step saves the configuration to the location specified by the CONFIG_FILE environment variable. |
| 1This command, the encapsulation command, and the clock rate command are documented in the "Interface Commands" chapter in the Router Products Command Reference publication.
2This command is documented in the "Frame Relay Commands" chapter in the Router Products Command Reference publication. 3This command and the ip helper-address command are documented in the "IP Commands" chapter in the Router Products Command Reference publication. |
You must use a DTE interface on the new router because the network will always provide the clock signal.
In the following example, the existing router's configuration file contains the commands needed to configure the router for Frame Relay AutoInstall on a serial line:
For AutoInstall to work correctly, the new router must be able to resolve its host name and then download a name-confg or name.cfg file from a TFTP server. The new router can resolve its host name by using a network-confg or cisconet.cfg file downloaded from a TFTP server or by using the DNS.
To set up a TFTP server to support AutoInstall, complete the following tasks. Step 2 includes two ways to resolve the new router's host name. Use the first method if you want to use a network-config file to resolve the new router's host name. Use the second method if you want to use the DNS to resolve the new router's host name.
| 1This command is documented in the "IP Commands" chapter in the Router Products Command Reference publication. |
The name-confg or the name.cfg file can contain either the new router's full configuration or a minimal configuration.
The minimal configuration file consists of a virtual terminal password and an enable password. It allows an administrator to Telnet into the new router to configure it. If you are using BOOTP or RARP to resolve the address of the new router, the minimal configuration file must also include the IP address to be obtained dynamically using BOOTP or RARP.
You can use the write network command to help you generate the configuration file that you will download during the AutoInstall process.
Note The existing router might need to forward TFTP requests and response packets if the TFTP server is not on the same network segment as the new router. When you modified the existing router's configuration, you specified an IP helper address for this purpose.
You can save a minimal configuration under a generic newrouter-confg file. Use the ip host command in the network-confg or cisconet.cfg file to specify newrouter as the host name with the address you will be dynamically resolving. The new router should then resolve its IP address, host name and minimal configuration automatically. Use Telnet to connect to the new router from the existing router and use the setup facility to configure the rest of the interfaces. For example, the line in the network-confg or cisconet.cfg file could be similar to the following:
The following host configuration file contains the minimal set of commands needed for AutoInstall using SLARP or BOOTP:
The preceding example shows a minimal configuration for connecting from a router one hop away. From this configuration, use the setup facility to configure the rest of the interfaces. If the router is more than one hop away, you also must include routing information in the minimal configuration.
The following minimal network configuration file maps the new router's IP address, 131.108.10.2, to the host name newrouter. The new router's address was learned via SLARP and is based on the existing router's IP address of 131.108.10.1.
If the new router is connected to the existing router using an Ethernet, Token Ring, or FDDI interface, you must configure a BOOTP or RARP server to map the new router's MAC address to its IP address. If the new router is connected to the existing router using a serial line with HDLC encapsulation or if you are configuring AutoInstall over Frame Relay, the tasks in this section are not required.
To configure a BOOTP or RARP server, complete one of the following tasks:
Note If the RARP server is not on the same subnet as the new router, use the ip rarp-server command to configure the existing router to act as a RARP server. See the section "Configure a Router as a RARP Server" in the "Loading System Images, Microcode Images, and Configuration Files" chapter of this manual.
The following host configuration file contains the minimal set of commands needed for AutoInstall using RARP. It includes the IP address that will be obtained dynamically via BOOTP or RARP during the AutoInstall process. When RARP is used, this extra information is needed to specify the proper netmask for the interface.
Connect the new router to the network using either an HDLC-encapsulated or Frame Relay-encapsulated serial interface or an Ethernet, Token Ring, or FDDI interface. After the router successfully resolves its host name, newrouter sends a TFTP broadcast requesting the file name-confg or name.cfg. The router name must be in all lowercase, even if the true host name is not. The file is downloaded to the new router where the configuration commands take effect immediately. If the configuration file is complete, the new router should be fully operational. To save the complete configuration to NVRAM, complete the following tasks in privileged EXEC mode:
| 1This command is documented in the "User Interface Commands" chapter in the Router Products Command Reference publication. |
 | Caution Verify that the existing and new routers are connected before entering the write memory EXEC command to save configuration changes. Use the ping EXEC command to verify connectivity. If an incorrect configuration file is downloaded, the new router will load NVRAM configuration information before it can enter AutoInstall mode. |
If the configuration file is a minimal configuration file, the new router comes up, but with only one interface operational. Complete the following steps to connect to the new router and configure it:
| 1This command and the enable command are documented in the "User Interface Commands" chapter in the Router Products Command Reference publication.
2This command is documented in the Router Products Getting Started Guide. |
On the Cisco 7500 series, you must format a new Flash memory card before using it in a PCMCIA slot. You can also format internal Flash memory (bootflash).
Flash memory cards have sectors that can fail. You can reserve certain Flash memory sectors as "spares" for use when other sectors fail. Use the format command to specify between 0 and 16 sectors as spares. If you reserve a small number of spare sectors for emergencies, you do not waste space because you can use most of the Flash memory card. If you specify zero spare sectors and some sectors fail, you must reformat the Flash memory card and thereby erase all existing data.
The system requires a monlib file for the format operation. The monlib file is the ROM monitor library. The ROM monitor uses the monlib file to access files in the Flash file system.
 | Caution The following formatting procedure erases all information in Flash memory. To prevent the loss of important data, proceed carefully. |
Use the following procedure to format Flash memory. If you are formatting bootflash, you can skip the first step. If you are formatting a Flash memory card, complete both steps.
Step 2 Format Flash memory.
To format Flash memory, complete the following task in EXEC mode:
The following example shows the format command that formats a Flash memory card inserted in slot 0 of a Route Switch Processor (RSP) card on a Cisco 7500 series.
When the router returns you to the EXEC prompt, the new Flash memory card is successfully formatted and ready for use.
You also format a Flash memory card to recover from locked blocks. A locked block of Flash memory occurs when power is lost or a Flash memory card is unplugged during a write or erase operation. When a block of Flash memory is locked, it cannot be written to or erased, and the operation will consistently fail at a particular block location. The only way to recover from locked blocks is to reformat the Flash memory card with the format command.
 | Caution Formatting a Flash memory card to recover from locked blocks will cause existing data to be lost. |
To enter configuration mode, enter the EXEC command configure at the privileged-level EXEC prompt. The router responds with the following prompt asking you to specify the terminal, NVRAM (memory), or a file stored on a network server (network) as the source of configuration commands:
Each of these three methods is described in the next three sections.
The router accepts one configuration command per line. You can enter as many configuration commands as you want.
You can add comments to a configuration file describing the commands you have entered. Precede a comment with an exclamation point (!). Comments are not stored in NVRAM or in the active copy of the configuration file. In other words, comments do not show up when you list the active configuration with the write terminal EXEC command or list the configuration in NVRAM with the show configuration EXEC command. Comments are stripped from the configuration file when it is loaded to the router. However, you can list the comments in configuration files stored on a TFTP or Maintenance Operation Protocol (MOP) server.
To configure the router from the terminal, complete the following tasks:
In the following example, the router is configured from the terminal. The comment "The following command provides the router host name" identifies the purpose of the next command line. The hostname command changes the router name from router1 to router2. By pressing ^Z, the user quits configuration mode. The command write memory loads the configuration changes into NVRAM.
NVRAM stores the current configuration information in text format as configuration commands, recording only nondefault settings. The memory is checksummed to guard against corrupted data.
As part of its startup sequence, the router startup software always checks for configuration information in NVRAM. If NVRAM holds valid configuration commands, the router executes the commands automatically at startup. If the router detects a problem with the NVRAM or the configuration it contains, it enters setup mode and prompts for configuration. Problems can include a bad checksum for the information in NVRAM or the absence of critical configuration information. See the publication Troubleshooting Internetworking Systems for troubleshooting procedures. See the Router Products Getting Started Guide for details on setup information.
On the Cisco 7500 series, the router startup software uses the configuration pointed to by the CONFIG_FILE environment variable to start up. When the CONFIG_FILE environment variable does not exist or is null (such as at first-time startup), the router uses NVRAM as the default startup device. When the router uses NVRAM to start up and the system detects a problem with NVRAM or the configuration it contains, the router enters setup mode. Refer to the Router Products Getting Started Guide for more information on the setup command facility. For more information on environment variables, refer to the "Cisco's Implementation of Environment Variables" section in this chapter.
On all platforms except the Cisco 7500 series, you can configure the router to execute the commands located in NVRAM. On the Cisco 7500 series, the same command configures the router to execute the configuration specified by the CONFIG_FILE environment variable.
To configure the router to execute the commands located in NVRAM or to execute the configuration specified by the CONFIG_FILE environment variable, complete the following task in privileged EXEC mode:
You can configure the router from the network by copying a configuration from a network server to your running or startup configuration. The following two sections explain these tasks.
You can configure the router by retrieving and modifying the configuration file stored on one of your network servers. To do so, complete the following tasks:
In the following example, the router is configured from the file tokyo-config at IP address 131.108.2.155:
You can copy a configuration file directly to your startup configuration without affecting the running configuration. On all platforms except the Cisco 7500 series, this task loads a configuration file directly into NVRAM without affecting the running configuration.
On the Cisco 7500 series, this task loads a configuration file directly into the location specified by the CONFIG_FILE environment variable without affecting the running configuration. If the CONFIG_FILE environment variable specifies NVRAM, the command functions as on all other platforms.
To copy a configuration file directly to the startup configuration, perform the following task in EXEC mode:
| Task | Command |
|---|---|
Load a configuration file directly into NVRAM or directly into the location specified by the CONFIG_FILE environment variable. |
The configuration register boot field determines whether or not the router loads an operating system image, and if so, where it obtains this system image. The following sections describe the router's process for using the configuration register boot field, your process for setting this field, and the tasks you must perform to modify the configuration register boot field.
The lowest four bits of the 16-bit configuration register (bits 3, 2, 1, and 0) form the boot field. The following boot field values determine if the router loads an operating system and where the router obtains the system image:
When loading a default system image from a network server, the router uses the configuration register settings to determine the default system image filename for booting from a network server. The router forms the default boot filename by starting with the word cisco and then appending the octal equivalent of the boot field number in the configuration register, followed by a hyphen (-) and the processor type name (cisconn-cpu). See the appropriate hardware installation guide for details on the configuration register and default filename.
You must correctly set the configuration register boot field to ensure that your router loads the operating system image as you intend. To set the boot field, follow this general procedure:
Step 2 Modify the current configuration register setting to reflect the way in which you want the router to load a system image. To do so, change the least significant hexadecimal digit to one of the following:
For example, if the current configuration register setting is 0x101 and you want to load a system image from boot system commands in the startup configuration file, you would change the configuration register setting to 0x102.
Step 3 Reboot the router to make your changes to the configuration register take effect.
You modify the boot field from either the hardware configuration register or the software configuration register, depending on the platform.
Use the hardware configuration register to modify the boot field of a
The hardware configuration register can be changed only on the processor card or with dual in-line package (DIP) switches located at the back of the router. For information on modifying the hardware configuration register, refer to the appropriate hardware installation guide.
Use the software configuration register to modify the boot field of a
To modify the software configuration register boot field, complete the following tasks:
Use the show version EXEC command to list the current configuration register setting. In ROM monitor mode, use the o command to list the value of the boot field in the configuration register.
In the following example, the show version command indicates that the current configuration register is set so that the router does not automatically load an operating system image. Instead, it enters ROM monitor mode and waits for user-entered ROM monitor commands. The new setting instructs the router to a load a system image from commands in the startup configuration file or from a default system image stored on a network server.
