I have had my cable modem set up in bridge mode with a 802.11n router connected to it for years now. Comcast switched from providing Norton AV to something called xFi that operates through my modem, It only works if the modem is not in bridge mode. Is the functionality of xFi worth reconfiguring my network or should I buy a Kaspersky, or Bitdefender, and keep my own router as a firewall.