9.3
Issues of Redundancy, Symmetry and Load Balancing
9.3.9 Single-homed connections
Single-homed customers have sites that connect to the Internet via a single connection to a service provider. The figure illustrates such a situation. These customers can usually be adequately served by pointing defaults toward the provider. The provider can also install static routing to reach the customer. This method is the least expensive and the most effective. The customer router does not need to learn any of the Internet routing table, substantially reducing memory usage and processing overhead. In this case, there is no issue of route symmetry because traffic has a single entrance and exit point.

Single-homed sites generally rely on a single connection to the Internet. Backup is not an issue. If the connection is lost, the customer can tolerate the outage until it is fixed. Obviously, such an arrangement would not satisfy mission-critical data communication requirements. A single-homed site with no backup access would not be appropriate for applications needing high levels of reliability.