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Customizing Cisco ROMmon Recovery

This section describes how to tailor Cisco NVRAM variables used by the Lantronix Cisco advanced driver when it needs to recover the OS image from ROMmon. More specifically, this allows you the ability to customize the variable settings used by the TFTPDNLD command when the Local Manager finds a router or switch in ROMmon and determines that the OS image needs to be recovered on the Cisco device.

You can customize the following ROMmon variable settings relevant to TFTPDNLD: IP address, subnet mask, default gateway, Ethernet interface, Ethernet interface speed, and duplex settings that override derived and default settings used by the Lantronix driver. For more information on Cisco's ROM Monitor and recovering a system image using TFTPDNLD, refer to Cisco's Troubleshooting and Maintenance: Using the ROM Monitor documentation for the 1800/2800/3800 Series Integrated Services Routers or the 1900/2900/3900 Series Integrated Services Routers.

Usage Notes

Customizing ROMmon variable settings adds value in the following situations:

  • TFTPDNLD will take place over the lowest numbered onboard interface of the device, unless a custom property is defined on the Local Manager..
  • TFTPDNLD will only be able to access networks which are not directly connected, once the DEFAULT_GATEWAY and IP_SUBNET_MASK environment variables are configured appropriately.

Feature Limitations

  • This feature is limited to Cisco routers and the switches that support the TFTPDNLD command in ROMmon.
  • This feature may not work on all Cisco routers and versions of IOS. Check the Cisco website to validate support for these ROMmon variables.

Required Privileges

  • config properties — Configure properties on an Local Manager port.
  • show properties — View properties on an Local Manager port.

Configuring ROMmon Variable Settings

The Lantronix advanced driver recovery from ROMmon functionality only works on Cisco devices that support the TFTPDNLD feature to download an OS image while in ROMmon. This feature utilizes Local Manager port properties to allow defining ROMmon variable settings that should be set by the Lantronix advanced Cisco IOS driver when it attempts to transfer an OS image to the router that is in ROMmon. Any user-defined ROMmon variable settings will override default settings used by the Lantronix LM.

The following ROMmon variables apply to all routers:

  1. IP_ADDRESS — IP address of the router
  2. IP_SUBNET_MASK — subnet mask of the router
  3. DEFAULT_GATEWAY — default gateway of the router

For routers with Fast Ethernet interfaces, the following ROMmon variables should be available to indicate which Fast Ethernet port should be used, as well as the speed and duplex setting for that interface:

  1. FE_PORT = [0 | 1]
  2. 0 indicates FastEthernet0/0 (this is the default interface chosen by the Cisco device)

  3. N indicates FastEthernet0/N (this is the last onboard FE interface)

  4. FE_SPEED_MODE = [0 | 1 |2 | 3 | 4]

  5. 0 indicates 10 Mbps, half-duplex
  6. 1 indicates 10 Mbps, full-duplex
  7. 2 indicates 100 Mbps, half-duplex
  8. 3 indicates 100 Mbps, full-duplex
  9. 4 indicates Automatic selection (default)

For routers with Gigabit Ethernet interfaces, the following ROMmon variables should be available to indicate which Gigabit Ethernet port should be used, as well as the speed and duplex setting for that interface:

  1. GE_PORT = [0 | N]
  2. 0 indicates GigabitEthernet0/0 (this is the default interface chosen by the Cisco device)

  3. N indicates GigabitEthernet0/N (this is the last onboard GE interface)

  4. GE_SPEED_MODE = [0 | 1 |2 | 3 | 4 | 5]

  5. 0 indicates 10 Mbps, half-duplex
  6. 1 indicates 10 Mbps, full-duplex
  7. 2 indicates 100 Mbps, half-duplex
  8. 3 indicates 100 Mbps, full-duplex
  9. 4 indicates 1 Gbps, full-duplex
  10. 5 indicates Automatic selection (default)

All user-defined ROMmon variable settings in the port properties must be the actual ROMmon variable name prepended with rommon. For example, to set the default gateway, configure the following property on the Local Manager port that is managing the router:

_rommon_DEFAULT_GATEWAY 192.0.2.254

Use the config properties command at the port level in the Local Manager to enter the port properties configuration editor.

[admin@LantronixLM (port1/4)]# config properties
[config properties]#

Once in the editor, you can use the ? command to view a list of possible configuration options.

[config properties]# ?
Allowable arguments are:
show
[propertyName] [propertyValue]
no [propertyName]
or 'exit' to save current values and quit config mode
[config properties]#
show

Display configured properties

{no} {property name} {property value}

Define property names. The no prefix will remove the property from the port.

Example: Instruct the Lantronix LM to transfer an image to the router, where auto negotiation should be used for interface GigiabitEthernet0/2, with an IP address of 192.0.2.142, a subnet of 255.255.255.0 and a default gateway of 192.0.2.254:

_rommon_IP_ADDRESS 192.0.2.142 _rommon_IP_SUBNET_MASK 255.255.255.0 _rommon_DEFAULT_GATEWAY 192.0.2.254 _rommon_GE_PORT 2 _rommon_GE_SPEED_MODE 5

exit

Exit the configuration editor.

Display Properties

Use the show properties command to view the properties on the Local Manager port:

[admin@Lantronix (port1/4)]# show properties
_rommon_DEFAULT_GATEWAY: 192.0.2.254
_rommon_GE_PORT: 2
_rommon_GE_SPEED_MODE: 5
_rommon_IP_ADDRESS: 192.0.2.142
_rommon_IP_SUBNET_MASK: 255.255.255.0