Inspiron 7437 and external ethernet adapter issue

Hi, i bought about 1 month ago an inspiron 7437 notebook (the one with i5 cpu). I bought also an usb3/ethernet usb adapter by dodocool (this one www.dodocool.com/.../dodocool-3-port-usb-3-0-hub-with-1-rj45-gigabit-ethernet-lan-wired-network-adapter.html). The problem with this adapter (or with the usb port) is that sometimes the ethernet goes down. It is like i'm disconnecting the adapter from the usb port. Sometimes the network returns, sometimes not. From about 2 weeks i switched from windows to linux fedora 21, and the issue is still present, but now I can give you some more informations on what's going on. This is the output of the dmesg tool:

[ 2137.778861] r8152 3-1.4:1.0 enp0s20u1u4: renamed from eth0
[ 2138.147925] usb 3-1: USB disconnect, device number 6
[ 2138.147934] usb 3-1.3: USB disconnect, device number 7
[ 2138.150248] scsi 5:0:0:0: rejecting I/O to offline device
[ 2138.150259] scsi 5:0:0:0: killing request
[ 2138.150340] sdb: detected capacity change from 15728640000 to 0
[ 2138.174590] usb 3-1.4: USB disconnect, device number 8
[ 2139.571268] r8152 3-1.4:1.0 enp0s20u1u4: intr_urb submit failed: -19

any idea on how to solve this problem?

Thanks