Complex sentence: The main issue with wireless network security is its simplified access to the network compared to traditional wired networks such as Ethernet; with wired networking one must either gain access to a building (physically connecting into the internal network) or break through an external firewall.
Split into simpler sentences: The main issue with wireless network security is its simplified access to the network compared to traditional wired networks such as Ethernet. With wired networking, one must either gain access to a building (physically connecting into the internal network), or break through an external firewall.