example is a corporation with centralized e-mail, financial, and sales applications. If the central site, the switch, or headquarters crashes, all sites connected to it are also out of service. This is illustrated in Figure 5-7 with the sites connected by Carrier Gigabit Ethernet. Seattle Internet Wide area network www.TechicIDDE LOS Angeles Centralized applications at headquarters Ethernet Houston Miami Figure 5-7 A hub-and-spoke design for centralized applications such as e-mail. The disadvantage here is that if e-mail or another application at the central site crashes, all sites lose access to it. Secondary hub-and-spoke A secondary "hub" is wired to a central site and connects to a cluster of smaller locations. The secondary hub sends traffic from the small locations to the backup central site. Mesh design All points on the network nodes connect to one another in a flat or non-hierarchical manner. Peer-to-peer networks for music sharing are examples of mesh networks. Carriers often design their core, backbone networks in a mesh configured with multiple failover routes. Mesh networks are the most expensive because they require the most links. See Figure 5-8 for mesh topology. www.TechnicalPDF.com Seattle Portland Maine Detroit St. Louis Los Angeles New York City Houston Louisiana Miami Each site can connect directly with every other site Figure 5-8 A mesh network connecting all sites together. Direct Dedicated Interconnections to the Cloud Customers have a choice of accessing the cloud from the Internet or via a dedicated connection. To access the cloud via the Internet, residential and business customers log in via their same broadband connections from which they access the Internet. These connections are sometimes slower and can cause delays if there is congestion in the Internet. They additionally are not as secure as direct dedicated connections. Large organizations with critical applications in the cloud often directly connect their locations to their servers and applications on the cloud. These direct in