Traditional WAN–based private networks used leased-line circuits from each site back to a corporate headquarters. These leased-line circuits were priced according to distance, making them expensive for geographically dispersed locations. These traditional WANs often used a hub-and-spoke model, requiring traffic going between branch offices to travel through the corporate headquarters. Despite these disadvantages, traditional WANs did offer the highest level of security and network performance. Corporations were paying for the full-dedicated bandwidth of the network.

Traditional WANs required highly specialized technical in-house resources and required corporations to manage their own networks. Older corporations often have extensive WAN infrastructure investments and are hesitant to adopt newer infrastructure implementations despite large potential cost savings. Figure 1 illustrates a typical WAN implementation where all traffic is cross-connected at the corporate headquarters. Each branch office or partner company is connected directly to the headquarters location.

Figure 1. Traditional WANs