US Patent 7500014 Network link state mirroring

Methods, apparatuses and systems allowing for network link state mirroring in intermediate network devices. A variety of intermediate network devices disposed between two network devices are operationally transparent to the two network devices. For example, a bandwidth management device disposed between a gateway router and a LAN hub or switch, is operationally transparent, to both network devices since the bandwidth management device, pacing or otherwise controlling packet flows, does not alter the essential routing or switching functions of the devices. The present invention promotes or enhances this operational transparency by mirroring the link state detected at a first network interface on other network interfaces. This functionality is highly useful in today's network topologies where information regarding failure of a link can be used to re-route traffic, alert a network administrator, and the like.