Abstract: A device is discovered on a network by means of a discovery protocol operated by a proxy and a protocol address for the device is obtained if required by the proxy, which requests a protocol address in accordance with a dynamic host communication protocol, then in the absence of response to that request attempts automatic private addressing and finally if necessary allows manual entry of a protocol address for the device.

Abstract: A network device which is for use in an Ethernet packet-based communication system has at least one port which is capable of auto-negotiation to select between half duplex and full duplex working on a link to which the port is connected. The device includes means for monitoring the existence of late collisions between packets on said link, means for monitoring the existence of packet fragments on the link, and monitoring means for detecting and correcting for a duplex mismatch on the link partner. This monitoring means is operative to determine whether there are any late collisions and in the absence of a detection of fragments to configure the port from a half duplex mode to a full duplex mode. The monitoring means is also operative to detect the presence of fragments when the port is in full duplex mode and thereby to provide an indication that a rule relating to network size is infringed.