Foreign ISPs Look to the Skies for Internet Access
telecoms-mag.com
Technical Update
Susan O'Keefe
While more people are becoming connected, the big frustration for
others is that the World Wide Web, in many cases, isn't easily
available worldwide. Because 80 percent of Internet traffic is
generated by access to U.S.-based Web sites, traffic flowing into and
out of the United States on terrestrial or undersea networks can be
slow and costly for Internet applications. In the case of many
developing nations, the frustration is that there may not be an existing
network to access the Internet at all. As they seek to meet market
demand, more and more foreign service providers are turning to fixed
satellite-based systems in geosynchronous Earth orbit (GEO) to
provide access to the Internet in the United States.
“Satellites are becoming an effective way to solve a lot of problems
foreign ISPs are having in providing their customers Internet services,”
said Frank Rosalia, managing consultant at Predictive Systems.
Indeed, this kind of connectivity via direct satellite-based links
appears to offer some strong advantages to ISPs and the number of
international connections using this method is growing rapidly. Bob
Egan, research director for Gartner Group, said that over the next five
years, satellite links will make up 7 percent to 12 percent of
international Internet connectivity. “Today that figure is about 3
percent, so that's substantial growth,” Egan said. “We are building a
global information society and satellites are the natural entity that glues
this world together.”
Comsat, which provides satellite links to foreign ISPs, estimates that
over the past two years, 30 percent of the company's growth has
come from demand for Internet services. “We're in the $100 million-
to $200 million-range in terms of our forecasted revenue from this
type of service,” said Susan Miller, vice president of engineering and
operations for Comsat World Systems. “It's not just Comsat: The
overall pie is growing.”
Providers of satellite-based Internet services cite several reasons for
their growing popularity.
Time to market: ISPs often use satellites to get their service off
the ground quickly, then proceed to build out landline infrastructure.
Although latency is an issue with satellites, Rosalia said most users
aren't bothered by the customary half-second delay experienced
when data traverses more than 22,000 miles on upward and
downward links.
Direct links: With satellite services, Internet traffic is sent directly
from the United States to the destination country without making the
multiple router-to-router hops used to negotiate Internet ground
traffic.
Asymmetrical service: Because inbound traffic usually consists of
a simple request for information and outbound requests consist of
multiple Web pages, the asymmetrical nature of satellites is a match
for Internet applications. Terrestrial services are generally symmetric.
“We see anywhere from a 4-to-1, up to an 8-to-1, ratio in terms of
the asymmetry between the outbound and inbound paths,” Miller said.
“That's a lot of unused bandwidth.”
Broadcast nature: Satellite data networks can handle
point-to-point traffic, but they are especially useful for
point-to-multipoint (IP multicast) traffic. Comsat uses this type of
application to serve Satellite Data Networks, a new ISP in South
Africa. Comsat currently supplies the ISP with 45 Mbps of dedicated
asymmetrical satellite capability. The service goes from South Africa
to Comsat's Teleport in Clarksburg, Md., where it connects to the
Internet through a local Digex POP. On the return path, traffic is
broadcast from the Teleport and received simultaneously by antennas
in Cape Town, Johannesburg and Durban. “One satellite location can
provide traffic to a number of locations at the same time with
addressing and capability built in,” Miller said. “Satellite links help to
optimize performance of those Internet services, whether they are
Internet over ATM, Internet over frame relay or straight IP-based
Internet services.”
Intelligent networking and management: In many cases, once a
service provider builds out its infrastructure with fiber, it continues to
use satellites to supplement its coverage. Hongkong Telecom recently
signed a deal with Intelsat to lease capacity to supplement its existing
cable network, citing the fact that the United States-to-Hong Kong
route registers the highest traffic volume among all incoming Internet
paths. The agreement consists of a
45 Mbps satellite link from the United States to Hong Kong and a
cable return link. Rosalia said existing protocols give networks being
built today the intelligence to choose the path of least delay:
“Messages are sent back and forth between the traffic
devices--routers--that indicate how much bandwidth is being utilized,
how much congestion there is and how many errors have been
detected before the packet is even sent.”
Although it's currently not a big play, Egan sees ISPs in the United
States continuing to grow their footprints via satellite-based Internet
services. This is especially true for regions just outside the boundaries
of large population centers where T1, digital subscriber line and
ISDN technologies haven't yet been rolled out. “It's all about how
many customers you can reach, and some ISPs may find this is their
best solution,” Egan said. He doesn't see satellites as much of a
competitive threat to landline access systems, especially in North
America. “Satellites will be complementary systems,” Egan said.
“There's still a lot of dark fiber out there and terrestrial networks have
very good economics. But satellites have good economics for pockets
where terrestrial systems don't play out and that's where I think you'll
see some growth.”
Susan O'Keefe is senior editor at Telecommunications. |
