Re: ESXi 5.5 nic teaming/LAG with trunking not working but on ESX 4.0 it works. Both are on same switch. What gives?

Hi

Do you share vmnics for Management ESXi and VM Network?

Try to follow the procedure described in this KB: VMware KB: NIC teaming using EtherChannel leads to intermittent network connectivity in ESXi

When trying to team NICs using EtherChannel, the network connectivity is disrupted on an ESXi host. This issue occurs because NIC teaming properties do not propagate to the Management Network portgroup in ESXi.

When you configure the ESXi host for NIC teaming by setting the Load Balancing to Route based on ip hash, this configuration is not propagated to Management Network portgroup.

Workaround

Note: To reduce the chance of network connection loss please change the vSwitch load balancing to Route based on IP hash using this method

1. Shut down all ports in the team from the physical switch leaving a single port as active.
2. Change the load balancing to Routebased on ip hash on the vSwitch and Management Portgroup.
3. Configure the port channel on the physical switch.
4. Enable the ports on the physical switch.

Notes: Using this method will prevent a connection loss when changing to a port channel. Also make sure that under the portgroup properties for vmk# used for management network you check mark the box "Enabled".