To the orbit and back

Satellite communications find a niche in the military and emergency services

Editor's note: This is part 2 of a three-part series on networking. Part 1 focused on efforts to consolidate networks. It can be found on Download’s Data Call at Next week's article will focus on telecommunications strategies.

The Federal Emergency Management Agency has nine vans outfitted with satellite dishes and computers that it uses to help local and state agencies in disaster areas coordinate rescue and restoration operations.

For example, as hurricanes battered the Florida coast last summer, FEMA officials wanted to establish emergency response centers as quickly as possible.

"Because we need our communications lines up so fast, satellite communications are our best option," said Rex Whitacre, chief of information technology district operations at FEMA.

FEMA is just one example of government agencies that rely on satellite communications. "There have been a few times when vendors tried to position satellite as a head-to-head competitor with terrestrial lines, but they eventually backed off from such statements," said Christopher Baugh, president of market research firm Northern Sky Research.

Instead of being used in widespread deployments, satellite communications have proven popular in three situations: when rapid deployment is needed, when no other telecommunications options are available or when an agency wants to have a backup option if its terrestrial link goes down.

Whitacre said satellites are suited to quick installations. Unlike terrestrial lines where deployment can take days, weeks or months, satellite lines can be up and running in a few days. Also, there is no work required on the provider's end, so the process requires only that the user install the satellite dish and connect it to its enterprise network. Government research organizations, particularly those tracking environmental and military issues, also may need new communication lines set up quickly.

Satellites are often the only communications option for agencies in rural areas. Terrestrial carriers have to undertake a cost justification process whenever they want to expand their networks. Typically, they only string new lines in densely populated areas because it doesn't make economic sense to run miles of fiber when there are only a few dozen potential customers.

Satellite technology does not have the same constraint. Because of their point-to-multipoint configuration, satellites transmit signals that can be picked up worldwide.

Government agencies that test various defense systems, monitor wildlife and energy resources, track the weather or provide emergency services often work in areas where there are no terrestrial lines so they rely on satellites to transmit information.

The military is a major user of satellite communications, especially for personnel who are stationed in remote locations where traditional telecom tools are out of reach.

One of the Army's challenges in Iraq is making sure that troops have the spare parts needed to keep their artillery and munitions operational. Soldiers have traditionally entered product requests into laptop computers and then passed the information to others further down the supply chain to move data from the field to Army warehouses. This process can take a few hours to months, depending on where the soldiers are stationed.

The Army conducted a pilot program last spring that outfitted soldiers with satellite transmitters that let them send this data electronically.

"The replenishing forces now have a better idea of where the troops are located and can move themselves closer to make the retooling process smoother," said Maj. Michael Devine, an Army assistant product manager.

The Sept. 11, 2001, terrorist attacks spurred agency interest in satellite services. "Government agencies now need disaster recovery plans that take into account the possibility that a central office can be wiped out," said Jeff Carl, director of marketing at Spacenet. Consequently, using alternative carriers won't work, but satellite links will, he said.

Users understand that satellite links have evolved from carrying data only to a mix of data, voice and video traffic. Video is a natural enhancement, and many satellite networks' primary function is to carry video traffic for cable and satellite TV services.

Recently, there has been growing interest in running voice over IP over satellite links. "There are more users working with VOIP applications than we anticipated," said Karl Fuchs, senior systems engineer at iDirect Technologies. "In some cases, it represents 90 to 95 percent of the traffic running over our satellite links." These users don't seem to be deterred by satellite call quality, which can resemble cellular connections.

Yet vendors still face a number of hurdles in their quest to expand their customer bases, especially when it comes to price. Although FEMA officials understand the value of satellite services, the bulk of its data, video and voice communications run on terrestrial lines.

"I can get a terrestrial T1 line for about $1,500 to $1,800 a month, and a comparable satellite link costs about 10 times as much," Whitacre said.

Prices for satellite communication service have been going down, and new consumer services, such as Internet access, are becoming comparable to terrestrial services, but satellite equipment pricing is still higher than terrestrial line costs.

At most, a government agency will pay a few hundred dollars for terrestrial equipment, which is often bundled in with services such as DSL. Terrestrial equipment is also fairly easy even for end users to install. In comparison, prices for satellite systems range from $1,000 to $5,000 per site, and only skilled technicians are able to deploy them.

Volume is another reason for the difference in equipment pricing. Terrestrial lines are used by many individuals and businesses, so network equipment vendors have been able to drive volume up and pricing down. Wired telecom services generate hundreds of billions of dollars in revenue annually in the United States, while satellite suppliers make only a few billion dollars.

An allegiance to proprietary protocols has also increased pricing. Although satellite vendors have moved to standard protocols, such as IP, they have not embraced those standards broadly. Three options are vying to become the standard for carrying IP traffic over satellite links.

The higher equipment expenses also stem partly from the difficulties that arise with the extra engineering work required with satellites. The pairing of IP and satellite networks is an unnatural one. A satellite link travels from a user's desktop to a network switch to a very small-aperture terminal (VSAT) — basically a satellite dish — that exchanges information with a spacecraft orbiting the earth 22,300 miles away.

Each time a data packet is shipped, it travels up from the sending system to the orbiting satellite and then back down to a receiving dish. The time needed to make the trip translates into one-quarter of a second. The framing, queuing and switching that the TCP/IP system relies on to ensure that packets arrive at the proper destination can increase that time to as much as half a second.

TCP/IP was designed for networks where delays are measured in milliseconds rather than tenths of seconds, so satellite delays can disrupt the acknowledgments and handshakes that are at the core of the network protocol.

When a transmission becomes garbled, TCP/IP adapts by slowing down. In a satellite network, that can mean that transmissions slow to a crawl.

"We can't alter the laws of physics, but we have found ways to mitigate the impact of delays," said Michael Cook, senior vice president at Hughes Network Systems. For example, packet spoofing fools a sending system into thinking it has received acknowledgments for shipped packets so that it continues to transmit data steadily.

In addition, satellite vendors have to account for physical and weather interference. Users and vendors have to make sure that they have a clear line of sight for transmissions.

In some instances, a company makes changes such as adding onto its office building or planting trees that block sight lines, forcing customers to move their satellite dishes or convince their neighbors to change something.

Heavy rain or snow can also slow transmissions and increase the number of dropped packets.

"We didn't have more than a minute or two when weather knocked our systems off-line during the hurricanes last summer," said John Fleming, a senior manager at Florida's Division of Emergency Management, which relies on satellite services to connect 140 sites statewide.

Although vendors have developed various schemes to address latency and weather problems, such techniques often add overhead to data transmissions, which lowers throughput.

The overhead also exacerbates a lack of bandwidth with satellite networks. Terrestrial carriers are upgrading their fiber-optic backbones to OC-192 links, which transmit data at up to 10 gigabits/sec, while satellite lines typically top out at 45 megabits/sec.

The bandwidth constraints are most evident when companies try to upload information. Unlike most terrestrial services, satellite services support different transmission rates for uploads and downloads.

Satellite networks were optimized for video transmissions, where complex images are shipped to tens, sometimes hundreds, of endpoints with little, if any, data sent up from those end stations. As a result, download speeds can be up to 20 times faster than upload rates.

Because of the limitations, satellite technology is expected to remain a niche rather than a mainstream application.

"Satellite services will experience slow and steady growth — about 4 percent to 5 percent per year — rather than the sharp and dramatic uptick in usage that would be needed to make it more of a threat to terrestrial lines," Baugh said.

Korzeniowski is a freelance writer in Sudbury, Mass., who specializes in technology issues. He can be reached at [email protected].

Vying for a slice of broadband

Broadband connectivity has evolved into a race between DSL and cable modems, with satellite services a distant third. The United States has about 25 million DSL and cable modem customers, compared with approximately 400,000 satellite service users.

Satellites have not gained widespread acceptance largely because of their high cost, reliance on proprietary equipment and low throughput. Based on Ku-band technology, existing services promise speeds of up to 1.5 megabits/ sec on the downlink and 128 kilobits/sec on the uplink, but they often deliver only half those rates.

Some satellite services vendors are ready to deliver services using newer technology on a higher frequency range called Ka-band. They hope its ability to boost bandwidth and reduce costs will increase their services' appeal.

Ka-band satellites have the potential to support downloads at speeds of up to 30 megabits/sec and uploads at 2 megabits/sec. They work with more modern, less expensive equipment than Ku-band satellites.

The first step in deploying new services is launching satellites capable of supporting them. In 2004, Boeing sent the Anik F2 satellite into orbit. It was designed to deliver Ka-band data services to small businesses and consumers.

WildBlue Communications began testing its satellite Internet services at the end of last year and plans to release them this summer. The firm expects to lower monthly satellite services fees from a high of $150 to about $50, which would make the company more competitive with cable modem and DSL.

Despite the potential of Ka-band services, questions exist about the level of user interest.

"In the consumer market, satellite vendors were never successful when trying to position their services against DSL and cable," said Karim Nour, industry manager at Frost and Sullivan, a market research firm. "These alternatives have been less expensive, and satellite has an inherent time delay. As a result, satellite broadband's appeal has been limited to rural and remote areas, though during the last decade, it never really penetrated that market either because of its high price and low quality of service."

Consequently, other satellite vendors delayed or altered their Ku-band satellite data services. Hughes Network Systems initially planned to use Boeing's Spaceway 1 and 2 satellites, which were launched last year, to support data networks, but DirecTV, which is a part owner of Hughes, decided to use them exclusively for high-definition home TV broadcasts.

"As of now, satellite providers are taking a wait-and-see attitude when it comes to Ka-band services," said Christopher Baugh, president of Northern Sky Research. "If WildBlue has a great deal of success, then competitors will be forced to respond, but as of now, they are waiting to see how much customer interest these services will generate."

— Paul Korzeniowski

Setting the standards

Some industry experts like to joke that vendors love standards because there are so many to choose from.

That statement holds true in the satellite market. Although the market is relatively small — a few billion dollars — and a limited number of players exist, it has spawned three standards for sending IP traffic over satellite links: Digital Video Broadcast Return Channel via Satellite (DVB-RCS), Data Over Cable Service Interface Specification (DOCSIS) and IP over Satellite (IPOS).

DVB-RCS was created by the DVB Forum, a vendor consortium that includes 260 satellite broadcasters, manufacturers, network operators, software developers and regulatory bodies from more than 35 countries. The group began working on the standard in 2002, and half a dozen devices that comply with it are now shipping.

DOCSIS was developed by CableLabs, a group of equipment companies that have worked together since 1988. In 1993, the group completed the standard, which outlines how cable modems distribute high-speed data communications via cable TV systems.

The standard has been widely adopted in that industry, and some satellite vendors use it to carry their IP traffic.

IPOS is a technique that Hughes Network Systems has relied on for its satellite terminals. The company formed the IPOS Forum to transform IPOS from proprietary to standard technology, and supporters include Hewlett-Packard, Intel and Microsoft. In addition, the group persuaded the Telecommunications Industry Association and the European Telecommunications Standardization Institute to ratify it as one of their standards.

Now that the vendors have decided which of the options they think is best, customers will determine whether any will emerge as a de facto standard.

— Paul Korzeniowski


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