IEEE standard for 802.5 Token Ring environments from an IBM development. A workstation (source) determines the router through the LAN internetwork. It sends a "discovery" or explorer packet along all active paths in the network, eventually reaching the destination host. Once received, the packet is sent back to the originator. Along the way, each bridge traversed adds its designator to the discovery packet. When it arrives at the originator, it contains complete routing information and the originator can send its data with that information attached. SR-compliant bridges generally need less processing power since most of the work is done by the originating workstation. A liability of SR is that the number of discovery packets traversing the network increases dramatically as the number of Token Ring LAN segments and internetworking devices between the stations grows.