Description of problem:
Two NIC port (intel 82599 fiber NIC) can be actived and ping sucessfully even if there is only one cable&module connected on one of two 10G ports under RHEL5.4 64bit Xen

Version-Release number of selected component (if applicable):
RHEL5.4 Xen 64bit

How reproducible:

Steps to Reproduce:
1.Load the BIOS optimized default,
2.Use a MLB of has two on-board NICs (intel 82599 Fiber NIC) to install RHEL5.4 xen 64bit via USB DVDROM or PXE. 
3.After OS installation completed, install the latest NIC driver with rpm package ixgbe-3.6.7.tar.gz.
4.Install module in eth0 and connect client with fiber optic cable, eth1 has no module and cable.  
5.Assign IP for two NIC ports.
6.Try to active all NIC ports and ping the server's two IP from client at the same time.

  
Actual results:
 1. If only one cable and module on one NIC port for instance eth0, can't active the other NIC port for instance eth1 under RHEL6.1 64bit. It is OK.
 2. If only one cable and module on one NIC port, both two NIC ports can be actived under RHEL5.4 xen 64bit. It was failed, the NIC should not be actived if no cable and module connected.
 3. If only one cable and module on one NIC port, can't ping the other NIC port from client under RHEL6.1 64bit. it is OK
 4.If only one cable and module on one NIC port, both two NIC ports can be ping successfully under RHEL5.4 xen 64bit. It was failed, the NIC should not be access if no cable and module connected.
5. When we used OS embed driver, to enlarge NIC loading, the NIC loading is nice, but after the driver loaded, the NIC loading is 0.

Expected results:


Additional info:
I doubt the driver impact the results, we will track it till the latest driver released, and also try OS embeded driver. But since the driver impact the NIC, so suggest to have a workaround to fix it.