Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

The %RF-4-MEMORY_SIZE_MISMATCH error message is displayed in the logs, and a duplicate interface VLAN appears in configuration of a Catalyst 6500 that runs hybrid mode

Core issue

The redundant Route Processors (RPs) have different memory configurations. To support the high availability feature, it is recommended that both RPs have the same memory configurations.

This issue is specific to MSFC2. It is not neccessary that the error message and the duplicate interface always occur together. If the ROM Monitor (ROMmon) version is not the minimum required to support the Cisco IOS  for MSFC2, this causes the error message to be displayed, even if the memory configurations are physically correct between both RPs. This issue can also lead to duplicate or bogus Switched Virtual Interfaces (SVIs) or interface VLANs.

This is an example:

router#show running-config

interface Vlan24
ip address
ip helper-address
no ip redirects
interface Vlan24
no ip address

router#show ip interface brief

Interface  IP-Address  OK?     Method   Status               Protocol
Vlan24  YES    manual up  up
Vlan24 unassigned  YES  unset  administratively down     down


To resolve the issue, perform these steps:

  1. Install the same amount of memory on both RPs.

  2. Ensure that the minimum ROMmon version is installed on the route processor according to the Cisco IOS version that is running on it. If not, upgrade the ROMmon by referring to the Upgrading the MSFC2 ROMMON section of Catalyst 6000 and Cisco 7600 MSFC2 ROMMON Software.


This should fix the duplicate interface VLAN issue as well. If the problem persists, contact Cisco Technical Support.