What do the blue, green and orange LED lights indicate?

Blue, orange (amber) and/or green generally indicate faster speeds might be possible, if you have purchased a faster speed service, or channel bonding is present. 

DS LED is Blue or Orange: Multiple downstream channels are bonded to support higher speeds FROM the Internet.
DS LED is Green: Downstream channel bonding is not being used.
US LED is Blue or Orange: Multiple upstream channels are bonded to support higher speeds TO the Internet.
US LED is Green: Upsteam channel bonding is not being used.
Ethernet LED is Blue: 1000 Mbps has been negotiated to support higher speeds between Ethernet ports on the Local LAN.
Ethernet LED is Green: Maximum speed has not been negotiated between devices on the LAN. Check the Ethernet settings for your PC adapter, or other attached device.

On some devices, LEDs on the back of the unit indicate connection speeds. Each Ethernet port on the back panel of the device has an LED to indicate its status when an Ethernet device is connected.

Ethernet LED is Orange: Ethernet device is connected to the cable modem at 10/100 Mbps speeds.
Ethernet LED is Green: Ethernet device is connected to the cable modem at 1000 speeds (Gigabit Ethernet).

Note: Multiple channels are required for downstream services such as 50 Mbps or higher.