Due to sky-high bandwidth costs and the high latency associated with satellite WANs, WAN optimization is becoming...
critical to any such network deployment.
In fact, some experts recommend that enterprises avoid satellite entirely if they can.
Often, with satellite WAN links, enterprises don't get what they paid for, Teicher said. He has customers who have paid for a T1 connection and received only 10 to 12 kilobits of usable bandwidth because of latency.
But for some enterprises, nothing but satellite will do, even though traditional broadband and wireless broadband options continue to proliferate.
Companies with branches or operations outside North America, Western Europe and the more wired parts of Asia, and companies that exist in vertical markets, such as oil and energy or rural convience stores, often find that satellite WANs are the only way to go, according to Joe Skorupa, a vice president of research at Gartner.
In these cases, a basic WAN optimization package can go a long way toward improving the situation.
"The basic WAN optimization technologies absolutely apply," Skorupa said. "Just with satellites, you have the worst of all worlds."
So the same techniques, like data de-duplication and TCP compression, which help boost terrestrial WAN connections can go a long way toward boosting satellite connections.
One satellite network service provider, ViaSat, even went so far as to acquire Intelligent Compression Technologies (ICT), a satellite WAN optimization company, in order to boost performance for its customers.
Just as with conventional wired and wireless WANs, the demand to squeeze more bandwidth, at lower cost, from satellite connections is only increasing.
"There are richer, higher bandwidth applications, like training videos, where you want to maximize bandwidth while minimizing latency," Skorupa said. For example, a remote gas station convenience mart that once used a satellite connection for point-of-sale terminals (PoS) might now want to update video advertisements at the cash register and the pump.
Increasing deployments of applications through the software as a service (SaaS) model have also caused problems for branches reliant on a satellite connection.
"If you're on satellite links, browser-based applications are going to be very problematic," Skorupa said. "Most of the SaaS guys don't think about [high latency]. The typical response is, 'It's the Internet; it'll just work.'"
In normal circumstances, SaaS applications would work fine, but introduce two to four seconds of latency in the connection, and the 70 requests the SaaS application usually handles in less than a second can completely destroy usability, even breaking the application altogether for the end user.
In addition to the high latency, low bandwidth and cost previously cited, high satellite packet loss is another recurring problem that Skorupa singled out, and it's one that not all WAN optimization tools address equally and one element where going with a vendor that specializes in satellite WAN optimization might pay off.
"With satellites, it's not unreasonable to have four to five higher order magnitudes of error rates than fiber," Skorupa said. "It may not be that way all the time, but you'll have bursts where it's error prone."
That can mangle the operations of SaaS applications and thick clients alike.
One solution, not offered by all vendors, is forward-error correction, which embeds a little extra data in the original data so that, if and when packets are lost, the transmission can be repaired without forcing a retransmission of the entire data stream.
"You just have to discover if you can afford that fixed overhead," Skorupa said.
With the right WAN optimization solution, the results can be remarkable.
Teicher said he has seen customers who were getting 10 to 12 kilobits of connectivity see a boost to 6 gigabits of usable bandwidth.