Allowing mobile devices, including those personally owned by employees, onto the network may be inevitable, but it doesn’t mean you have to throw up your hands and abandon all hope of security. You can plan for safe deployment of mobile devices, even when those devices don’t belong to the company. Check out this article on safely enabling mobile devices, which is part of a multi-part series on planning for network security:
http://www.securityweek.com/network-security-planning-steps-safely-enabling-mobile-devices