I can't ping to default gateway over usb connection

My BBB is connected to my Windows 10 Host pc over usb.
It is currently not pinging to default gw 192.168.7.1 even after I typed ‘route add default gw 192.168.7.1’.
Here is my connection setting over usb.

usb0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.7.2 netmask 255.255.255.252 broadcast 192.168.7.3
inet6 fe80::76e1:82ff:fe8d:c9a9 prefixlen 64 scopeid 0x20
ether 74:e1:82:8d:c9:a9 txqueuelen 1000 (Ethernet)
RX packets 4093 bytes 471965 (460.9 KiB)
RX errors 0 dropped 6 overruns 0 frame 0
TX packets 3354 bytes 506179 (494.3 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

Can anyone explain why ping doesn’t work?