A wireless communication network may include a plurality of mobile nodes each including at least one wireless transceiver, a directional antenna and an omni-directional antenna connected to the at least one wireless transceiver, and a controller for controlling the at least one wireless transceiver. The notification system determines when an in-band notification is to be sent to clients. In some embodiments, the distributed indexing system includes an index server that handles indexing requests and forwards the requests to the appropriate distributed systems. Over time, used process water is cleaned by settling, by use of a filter, or by use of some other mechanical separating equipment, and the cleaned process water is recycled. Alternatively, it may be determined whether the D bit specified in the registration request packet is set and the care-of address specified in the registration request packet is a collocated care-of address. An optical lens that exhibits a selected magnification level is positioned to overlay the user display.