As can be seen in Figure 1, MPOA utilizes LANE, which is used to provide the necessary bridging support. The need for bridging is a natural consequence of the support for virtual routing, in two regards. One capability of the MPOA system is to allow conductivity to a single subnet to be distributed across several edge devices. In order to ensure that the collection behaves as a single subnet, bridging is used. Specifically, a logical, virtual bridged LAN is created to support the subnet, with connectivity on all participating edge devices.
Communication exists without excess coordination.
The IETF has specified a flexible, extensible protocol that supports these needs. This protocol is used by MPOA for its registration and address resolution needs. The AHFG also may use default forwarding when it does not wish to establish a direct virtual circuit to its communications peer. Specifically, the ICFG accepts registrations from MPOA AHFG, and answers queries about those hosts. The DFFG provides default forwarding services to those ATM attached hosts.