Patent ID: 7752672
Filing Date: 2010-07-06
Classification: H04L

Abstract:
1. A method of operating a communications port of a network communications device, comprising: maintaining capability information indicating that under normal operating conditions a communications link coupled to the communications port is capable of operating in a secure mode in which communications signals of the communications link are unintelligible to an intruder having an unauthorized physical connection to the communications link; detecting occurrence of a link event of a type that can invoke an automatic communications-mode control mechanism to change the operating of the communications link to a non-secure mode in which communications signals of the communications link are intelligible to such an intruder; and based on the capability information, responding to the detected occurrence of the link event by preventing the automatic communications mode control mechanism from changing the operating of the communications link to the non-secure mode, wherein the automatic communications-mode control mechanism comprises an auto-negotiation process conducted between the communications port and an end device coupled to the communications link, the auto-negotiation process being conducted in a secure mode to impede the detection of the content of the auto-negotiation process, and wherein standard auto-negotiation pulses are employed to serve as enemy indicators indicating the presence of the powered device, and non-standard signals are employed to serve as link negotiators to force operation of the communications link in the secure mode.