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Headsup : CSCtw68712 UCS C-series and interrupt remapping issue

Hi CUCM Team,

We recently discovered a defect in the BIOS on the UCS C-series servers :

CSCtw68712    UCS C-series bios fix for VMware ESx intel interrupt remapping issue

Symptoms on CUCM server :

  • missing keepalives (SDLLinkOOS)
  • phone unregister
  • high IO wait
  • delay in dataprocessing ( SIP messages out of order)

Solution : Upgrade BIOS on the UCS C-series servers to 1.4.3c

Disable remapping on the UCS server not enough to solve the problem.

The BIOS version is not upgraded when upgrading the ESXi to version 5.0, it needs to be upgraded manually.

For more information on interrupt remapping :

For more information on how to upgrade the BIOS :

Here's a link to the 1.43c cimc/bios huu .iso image for the C210

Here is the link for the C200

Here's a link to the upgrade guide.

Thank you,


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