This section provides important information to describe the different configuration options used to populate the required BGP AD and generate the LDP generalized pseudowire-ID FEC fields. There are a large number of configuration options that are available with this feature. Not all these configuration options are required to start using BGP AD. At the end of this section, it will be apparent that a simple configuration will automatically generate the required values used by BGP and LDP. In most cases, deployments provide full mesh connectivity between all nodes across a VPLS instance. However, capabilities are available to influence the topology and build hierarchies or hub and spoke models.