Cisco Cisco IOS XR Software Release 4.0

The rp mgmtethernet forwarding command is not supported on the 
Cisco XR 12000 Series Router.

Enabling the Lawful Interface feature triggers the L2-PRECAM-2-HW_RESOURCE_FAILURE 
message on Engine-3 linecards. This error reflects that your configuration has used up all available 
look-up registers (LUREGs). 

There is no direct workaround for this issue as its a hardware limitation. Only way to recover from 
this issue is to reduce feature scale. You need to identify the features which use LUREG at 
PreCAM1 and remove one or more of the features depending on LUREG requirements of the feature 
being added.

mpls traffic engineering igp-intact command—This command must be used only when policy 
based tunnel selection is configured for all tunnels originating on the device.

Disable/Enable RSVP Message Checksum Starting with Cisco IOS XR Software Release 4.0.2, 
RSVP will, by default, compute and set the checksum field in all outgoing RSVP messages. Also, 
RSVP will verify the checksum field on all RSVP messages received to insure RSVP message 
integrity.

A CLI is provided to override this Cisco IOS XR Software Release 4.0.2 default behavior and go 
back to pre Cisco IOS XR Software Release 4.0.2 behavior such that RSVP neither computes/sets 
the RSVP checksum on outgoing RSVP messages, nor verifies the checksum on received RSVP 
messages. The command to execute to revert to the pre-Cisco IOS XR Software Release 4.0.2 
behavior is:

Router(config)#rsvp signalling checksum disable

When the rsvp signalling checksum disable command is configured, RSVP sets a zero 
checksum in all outgoing RSVP messages, and ignores the checksum field on all received 
RSVP incoming messages.

For Cisco IOS XR software Release 4.0.0 and above the hw-module location <LOC> reload warm 
command has been disabled. This means that the warm reload feature has been disabled.

Cisco IOS XR Software Release 4.0.3 requires a 2-GB Flash Disk as a minimum. If your 
Cisco XR 12000 Series Router currently uses a 1-GB Flash Disk, you must upgrade it to 2-GB before 
upgrading to Cisco IOS XR Software Release 4.0.3. The PCMCIA 1-GB Flash Disk was the default size 
for the Cisco XR 12000 Series Router running Cisco IOS XR Software Release 3.6 and earlier.

In Cisco IOS XR Software Release 3.6 and later releases, disk partitioning is supported. Partitioning of 
a 2-GB disk is possible but not required. Partitioning of a 4-GB disk is required.

A 4-GB Flash Disk can be installed instead of the 2-GB for greater disk storage.

To upgrade from a 1-GB flash disk to a 2-GB or greater flash disk, refer to the Flash Disk Upgrade Tasks 
link on the following Cisco XR 12000 Series Router Installation and Upgrade URL: