Abstract: A local network is interfaced with one or more external network elements via a gateway that implements an address substitution mechanism for ensuring that communications between devices attached to the local network are not routed through an external network as a result of, e.g., disparity in their remotely-assigned Internet protocol (IP) addresses. In accordance with the invention, the gateway is configured to intercept communications from devices on the local network in order to determine remotely-assigned IP address information for those devices. After such information is determined for a given device, the gateway creates a set of address substitution information that includes sub-network compatible addresses for use by other devices on the local network when communicating with the given device.

Abstract: An autosensor or other communication system processing device determines which of a number of available link variants is required for a particular communication link that couples customer premises equipment (CPE) or another type of device to a network. The autosensor examines responses to messages sent over the link in order to determine one or more link variants associated therewith. The CPE or other device may then be automatically configured to support the determined link variant(s), e.g., by activation of an appropriate protocol entity in the CPE or other device. For example, CPE may be coupled to a network via an Asynchronous Transfer Mode (ATM) virtual circuit (VC) established over a digital subscriber line (DSL). In such an arrangement, multiple protocols may be encapsulated within the ATM cells, with each of the multiple protocols corresponding to a link variant. The CPE in this case may correspond to an ADSL termination unit-receive (ATU-R) device, or other type of gateway.