Along with the benefits of new service revenues and reduced capital and operating costs, Voice Over IP (VoIP) networks present several design, implementation, and regulatory challenges to service providers and Businesses.

The primary concern has been ensuring Quality of Service (QoS) i.e. making sure that a Voice Over IP call has the same level of voice quality as a call made over a traditional telephone network. With wide area networks, techniques such as MPLS and tagging are used to prioritize voice packets so that data streams contending for bandwidth in the same network don't degrade voice calls. With-in a building, it may be necessary to upgrade the capacity of the LAN when migrating to VoIP.

Other concerns include:

• Maintaining regulatory compliance such as those related to 911 calls or related to power, privacy and security etc.

• Compatibility with still evolving (and too many) VoIP protocols.

• Meeting Customer Expectations for reliability and ease of use. The fact that Internet services don't work during power outages merits special consideration especially in case of 911 emergency response situations.