Knowledge Base

One possible reason for this is that the adapter is unable to negotiate a link with the switch.

The IEEE standard specifies that 1000Base-T ethernet adapters and switches should autonegotiate to establish a link. The link comes up only if the devices at both ends of the link have the same autonegotiation setting (either enabled or disabled). Some models of gigabit ethernet switches do not allow disabling autonegotiation on their ports. In such a case, you must enable autonegotiation on the network adapter.

Note: This applies both to gigabit ethernet adapters assigned to the service console and to those assigned to virtual machines.

By default, gigabit network adapters have autonegotation enabled. If you force settings, ensure that autonegotiation remains enabled. For example, you should not specify auto_speed=0 in /etc/vmware/hwconfig if the Broadcom gigabit ethernet adapter is assigned to virtual machines, or in /etc/modules.conf if the adapter is assigned to the service console. Doing either of these disables autonegotiation on the Broadcom adapter and the link does not come up.

When you use the the ESX Server management interface to choose a speed and duplex setting for Broadcom gigabit adapters assigned to virtual machines, /etc/vmware/hwconfig is edited to include auto_speed=0.

To correct this, edit the /etc/vmware/hwconfig file and remove instances of auto_speed=0.

For more information about network adapter settings for an ESX Server machine, see www.vmware.com/support/kb/enduser/std_adp.php?p_faqid=813.