If you're running your own VoIP network, you may face some of these same problems. VoIP networks offer greater user mobility and easier moves, adds and changes, but many VoIP systems require extra software, equipment and processes to deliver e911. Investigate the e911 capabilities of your system and make them clear to your users. For example, users should know that if they bring their VoIP phones home, it probably won't give them accurate e911 services automatically. If you are buying a VoIP system, make sure mobile e911 is spelled out in your requirements.