You can monitor the status of a link aggregate in OS X Yosemite and OS X Server using the Status pane in the Network pane of System Preferences.
Open System Preferences.
Click Network.
From the list of network interfaces on the left, select the link aggregate port virtual interface.
Click Advanced in the lower-right side of the window.
Select the Bond Status tab.
The Sending and Receiving status indicators are color-coded. Green means the link is active (turned on) and connected. Yellow means the link is active but not connected. Red means the link can’t send or receive traffic.
The Status pane displays a list containing a row for each physical link in the link aggregate. For each link, you can view the name of the network interface, its speed, its duplex setting, the status indicators for incoming and outgoing traffic, and an overall assessment of the status.
To view more information about a link, click its entry in the list.