The US military plans to test an internet router in space, in a project that could also benefit civilian broadband satellite communications.
Cisco Systemsand Intelsat General, a subsidiary of Intelsat, are among the companies selected by the US Department of Defence for its Internet Routing In Space (IRIS) project, which aims to deliver military communications through a satellite-based router.
Potential non-military benefits of the IRIS program include the ability to route IP traffic between satellites in space in much the same way packets are moved on the ground, reducing delays, saving on capacity and offering greater networking flexibility, says Lloyd Wood, space initiatives manager in the Global Defense, Space & Security division of Cisco.
To send a message from one remote terminal to another via satellite today requires the first terminal to send the data to the satellite, from where it is bounced back to an earth station for routing. The earth station re-transmits it to the satellite on a different frequency, selected depending on its destination, and the satellite bounces it back to its destination. With the router in space, the satellite can pick the channel used to send the message to its destination. By eliminating the message's round trip to the earth station, operators can increase satellite capacity and reduce transmission times between remote terminals by using fewer hops and fewer frequencies for each message.
For the IRIS program, satellite operator Intelsat will manage the three-year project, while Cisco will provide IP networking software for the on-board router.
After testing, the technology will be available for commercial use.
Although satellites have been passively relaying IP traffic since the 1970s, the use of an orbiting satellite as an active part of the internet is a more recent development, according to Wood.
Traditionally, communication signals that come up to a satellite in either the C-band or the Ku-band go down in the same band, he says. They require separate transponders that don't communicate with each other.
Internet routing technology being tested in the IRIS project will enable this communication by "decoding what comes up in the C-band or Ku-band and interconnecting the two," says Wood.
"You save on delays and capacity by not having to go back to the ground," he says. "And once you have smarter satellites, you can treat them as not completely separate but as part of your IP network and manage them as you do your IP networking assets on the ground. They become fully integrated with your terrestrial network, allowing you to take advantage of existing management tools and also decrease the number of ground stations."
The IRIS payload will support network services for voice, video and data. The system is designed to support IP packet Layer 3 routing or multicast distribution, which can be reconfigured on demand.
The Defense Information Systems Agency will have overall responsibility for coordinating the use of IRIS technology among government users and leveraging IRIS capability once the satellite is in space.
The satellite is set for launch in the first quarter of 2009.