SAN FRANCISCO, 6 JULY 2009 - At its user conference in San Francisco last week, Cisco Systems boasted about the 30 new businesses it's developing. One is scheduled to launch by the end of this year -- in a very literal way.
The company that pioneered the Internet router is about to enter a new frontier, sending one into geostationary orbit on a satellite. It's the first big step in a U.S. Defense Department-led initiative, called Internet Routers In Space (IRIS), that could eventually make it easier and less expensive to get high-speed Internet access where wires and cables don't reach.
Satellites carry Internet data and connect to the Internet through base stations on the ground, but they are really a separate network, said Greg Pelton, general manager of IRIS at Cisco. An Earth station beams a signal up to the satellite at a certain frequency, and the craft bounces it back down to another, predefined Earth station. Users, such as service providers and government agencies, have to lease that frequency and sit on it whether they are using it or not.
Satellite links represent discrete point-to-point connections in an Internet that's designed to route packets around the world on any peering network and any kind of physical link. That's because there are no routers in space, according to Pelton. If communications satellites had routers, they could take in IP (Internet Protocol) packets and send them to a variety of places, via different Earth stations or other satellites, forging new links whenever needed. Rather than having to pick a particular link and lease it, users could just pay for an Internet service that uses satellites as part of its physical backbone.
Routing in space would also cut down on lag times, satellite consultant Mark Chartrand pointed out. Because routing can only be done on the ground today, data packets have to be sent to Earth and back every time they are forwarded from one satellite link to another, he said. That adds one-quarter of a second of latency per round trip. Routers could solve that.
"It makes satellites smart, and it avoids hops," Chartrand said.
Some satellites, such as those used by Iridium, can communicate directly with each other, but not using the universal standard of IP. In fact, current satellite technology is largely made up of expensive, proprietary equipment, Chartrand said.
Two recent developments have readied the satellite industry for IP routers, according to Pelton. One is an explosion in the capacity of satellites, from a typical capability of about 2Gb per second (Gbps) to as much as 150Gbps. This became possible because of technology that let satellites tap into a set of frequencies called the Ka band, as well as a new antenna technology called "spot beams." Rather than using one antenna to reach a whole continent, some satellites now have many antennas, each focused on a certain area. All these "spot beams" can use the same frequency at the same time, which multiplies how much data can be transmitted on that frequency, Pelton said.
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