1999-05-17 Special Called Meeting and Workshop Meeting

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The Ricochet Wireless Network Overview Page 2 of 5 The Ricochet network consists of shoebox-sized radio transceivers, also called Microcell Radios, which are typically mounted to street lights or utility poles. The microcells require only a small amount of power from the street light itself (connected with a special adapter) and are otherwise self-contained units (no other wiring or connections are necessary). They are strategically placed every quarter to half mile in a checkerboard pattern. Each Microcell Radio employs 162 frequency -hopping channels, and uses a randomly selected hopping sequence. This allows for a very secure network, and enables many subscribers to be using the network at the same time. Installation of each Microcell Radio takes less than five minutes. Within a 20-square mile radius (containing about 100 Microcell Radios) Ricochet installs Wired Access Points, or WAPs, which collect and convert the RF packets into a format for transmission to the wired IP network backbone, through a T1 frame -relay connection. Radio packets are routed from Microcell Radio to Microcell Radio through the Ricochet network in the most efficient manner possible. Each WAP and the Microcells Radios that report to it can support thousands of subscribers. Consequently, data packets between a Ricochet modem and Microcell Radio may take different routes during transmission. They can be routed to another Ricochet modem or to one of the gateways which allows subscribers to access other services. Currently, Ricochet supports gateways to the Internet, to the telephone system, to an X.25 network or to corporate Intranets or LANs. The telephone system gateway provides Telephone Modem Access. TMA can also be used to connect to on-line services such as AOL and CompuServe. For more details about Ricochet Gateways, refer to the Ricochet Gateway Mkxoce6 Rados on Street IghtsrU6ldy poles Modem Redo a Overview. ComptterDaAce M,red Access Polnt _ � it Name Server Roster Gateway Network Irtercomectlon Facility Mane{, Irtrands, LANs, CompuServe,AOL and other m4ne sa-Aces l Ricochet is a digital packet -switching radio network with a nationwide wired backbone. The wired backbone is based on conventional IP technology and routes traffic throughout a metropolitan service area or through Ricochet's Network Interconnect Facilities, or NIFs, if the packet has to travel across country. A NIF is simply. a router, which gathers data packets from the WAPs, with a few large leased lines which connect it with other NIFs in other metropolitan service areas. An integral piece of the Ricochet Network backbone is the Name Server, which provides connection validation and path information. All connection requests from a Ricochet modem must first be validated by the Name Server. This automatically occurs every time a Ricochet http://www.ricochet.net/netoverview.html 8/31 /98