1) The white box is the modem. Without that the internet connection wouldnt be possible. You black box is just a router which takes one connections and splits into "n" connections. It cannot decode the fiber optic signals directly without thst white box's help..u setup is ok, there is no problem and dont mess with that..
2) The Netvigator website says " Bandwidth Specification refers to network specifications of the subscribed Services for the broadband line connected from the modem at your Premises to the first piece of network equipment or central office of the NETVIGATOR network. For Fiber-to-the-home Plans, bandwidth specifications of 1000M correspond to a maximum upstream and downstream bandwidth of 1000Mbps. The actual speed you experience using the Service will be less than the network specifications and affected by your device, technology, network and software used, network configuration and coverage, usage levels, international bandwidth and extraneous factors."
So technically the 1GB speed is from your computer to netvigator server..your speed tests using speetest.net or myspeedmeter will be mesuring speeds to and from random servers located at HK not necessarily from Netvigator server...so the speeds you are getting is quite good..