links to sites within the organization, commuters, and mobile workers. Organizations use security protocols to keep their IP VPNs secure from hackers. The term "IP VPN" is not used consistently to mean the same thing. Some organizations refer to it synonymously with MPLS. They might refer to VPNs that operate over the Internet simply as VPNs. Using IP VPNs between Offices Organizations use IP VPNs to link sites together SO that remote offices are able to share resources such as centrally located e-mail servers, Internet access, and applications. A particular difference between IP VPN and MPLS networks is that Broadband and Wide Area Network Services organizations that use IP VPNs only pay for Internet access. This is a major cost advantage in favor of IP VPNs. Some companies do pay carriers for security services to screen incoming traffic for viruses. However, IP VPNs do not offer Quality of Service (QoS). This makes them somewhat problematic for transmitting group video conferences over the Internet. Organizations can add capacity to their access lines, but they have no control over the Internet itself. If an organization experiences congestion on its access circuits, it has the option of adding access lines or increasing the capacity of its existing access circuits. It can add T1 lines, upgrade its T1s to T3, upgrade Carrier Gigabit Ethernet to higher speeds, or add Carrier Gigabit Ethernet and cancel the T3 service. However, IP VPNs do not guarantee QoS. IP-based networks such as the Inter- net are connectionless. With connectionless networks, each packet is transmitted as a separate entity. A path is not saved in the network for the entire transmission. Rather, every packet can take a different route, and if there is congestion on a particular route, packets are dropped. The router at the receiving end reassembles packets into their original form, minus the dropped packets. Dropping parts of voice or video streams can result in poor quality. As more video traffic is sent over the Internet from mobile devices 