Information About ROM Monitor Firmware
The ROM Monitor, which is also known as ROMMON, is a bootstrap program that initializes the hardware and boots the Cisco IOS XR firmware when you power on or restart a Cisco CRS router. ROM Monitor upgrades can be required to resolve firmware defects or support new features. Typically, ROM Monitor upgrades are infrequent and not required for every Cisco IOS XR software upgrade.
The ROM Monitor firmware on all Route Processors (RP)s must be compatible with the current Cisco IOS XR software release running on the router before it is upgraded to the latest Cisco IOS XR Software Release.
If the router is brought up with an incompatible version of the ROM Monitor software, then the standby RP may fail to boot. If a boot block occurs in a multishelf system, contact your Cisco Technical Support representative for assistance.
Cisco CRS multishelf systems should be upgraded to ROMMON release 1.54 (minimum version required) before being upgraded to Cisco IOS XR Release 4.2 or later, to ensure that RPs are assigned the correct rack numbers during a system boot.
Before upgrading the ROMMON for PPC-based line cards (such as CRS-X), you must upgrade the monlib (using the format bootflash: location node-id monlib-only command) to the compatible version mentioned in the Software/Firmware Compatibility Matrix. For Cisco IOS XR Release 5.1.1, the monlib version required for PPC-based line cards is 3.6.
Note |
ROMMON versions are backward compatible. You need not downgrade the ROMMON versions if the current version is higher than the listed compatible version. |
ROMMON A and ROMMON B
Each node in a Cisco CRS router includes two copies of ROM Monitor: ROMMON A and ROMMON B. During power on, ROMMON A loads first. If ROMMON A detects the presence of ROMMON B, it checks the compatibility and integrity of the ROMMON B code. If ROMMON B passes these tests, ROMMON A passes control of the router to ROMMON B.
Normally, you only upgrade ROMMON B. ROMMON A is a backup for ROMMON B. When you upgrade the ROMMON B, the router uses the unmodified ROMMON A if the ROM Monitor upgrade is interrupted or fails for any reason.
Failures are most likely to occur during ROMMON upgrades or downgrades and unlikely to fail during normal usage. A failure in ROMMON A results in an inactive card that must be returned to the authorized merchandiser.
By default, on an MSC/FP-140 and PRP ROMMON, there is a dedicated piece of hardware that chooses to boot ROMMON B. This resets the board and selects ROMMON A in the event of a boot-timer expiry, which means that ROMMON A and ROMMON B are fully independent and identical images.
Note |
|
Upgrading or Downgrading a Single Node or All Nodes
The upgrade and downgrade procedures for ROMMON firmware are the same. Install a higher version to upgrade the firmware, or a lower version to downgrade the firmware.
ROM Monitor operates on every node within the router. During an upgrade or downgrade, the ROMMON firmware is copied into hardware EEPROMs in the router.
For most upgrades, we recommend upgrading or downgrading the ROMMON firmware on all nodes. You can also upgrade or downgrade a single node, which is useful when moving a card between two routers or adding a card that is not running the correct ROM Monitor version. When you upgrade a single node that uses ROM Monitor in both the CPU0 and SP modules, such as a line card node, we recommend that you upgrade both modules to the same ROM Monitor version.
Reloading Nodes After a ROMMON Firmware Change
The new ROMMON firmware is not active on a node until the card is reloaded. For example, if you upgrade a single node, you must reload that node only after the upgrade. If you upgrade or downgrade all nodes, you must also reload all nodes to activate the new ROMMON version.
To gracefully reload all nodes, reload the standby RP, perform a redundancy switchover, reload the second RP, and then reload all other nodes in the system.
If the router does not contain a redundant standby RP, or if you wish to perform a cold restart, you can also reload all nodes at the same time, including the primary RP. Remember that a cold restart results in router downtime while the cards reboot.
ROM Monitor Compatibility with Cisco IOS XR Software
The ROM Monitor firmware on all RPs must be compatible with the Cisco IOS XR software release currently running on the router before a Cisco CRS system is upgraded to latest Cisco IOS XR Software Release. If the router is brought up with an incompatible version of the ROM Monitor software, the standby RP may fail to boot.
This table describes the minimum ROMMON version required for Cisco IOS XR Software Release:
Cisco IOS XR Software Release | Minimum ROMMON version |
---|---|
4.1.x | 2.03 |
4.2.x | 2.06 |
4.3.x | 2.07 |
5.1.1 | 2.08 |
5.2.x | 2.09 |
5.2.2 | 2.10 |
5.3.x | 2.10 |
Note |
Cisco IOS XR Software Release R5.1.0 is not applicable for CRS platform. Therefore, the minimum ROMMON version of 2.08 is applicable only from Release R5.1.1 onwards. |
In addition, Cisco CRS multishelf systems should be upgraded to ROMMON release 1.54 before being upgraded to Cisco IOS XR Software Release 4.2.0 or later, to ensure that RPs are assigned the correct rack numbers during system boot.
After you upgrade to latest Cisco IOS XR Software Release, you should upgrade the ROM Monitor firmware to the recommended version for that release.
Note |
If the ROM Monitor firmware is not compatible with the Cisco IOS XR software currently running on the router, refer to the documentation for your currently running software release for instructions on upgrading the ROM Monitor firmware to a compatible version. After you upgrade to latest Cisco IOS XR Software Release, use the instructions in this module to upgrade your ROM Monitor firmware to a version compatible with that release. |
Overriding a Boot Block in the Standby RP
If a Cisco CRS system is upgraded to latest Cisco IOS XR Software Release, before the ROM Monitor firmware is upgraded to a compatible version, a boot block may occur in the standby RP.
Note |
If you are running Cisco IOS XR Software Release 3.2.6, or an earlier release, RP/B is not supported in Cisco CRS systems (single-shelf or multishelf). RP/B was introduced in Cisco IOS XR Software Release 3.3.0 with a minimum supported ROMMON version of 1.38. |