For instance, if a ship were at sea with no landing scheduled that day, up to 300 passengers might be logged on to the Internet at the same time. "We would have to look at the itinerary and decide if we prioritise the admin traffic, what is that going to do to the passenger traffic?" he says.
With Riverbed optimisation, that kind of time-consuming decision comes up less often. "By deploying this type of technology, we remove a lot of that manual analysis," he says.
Tests by the cruise line find that a 20.3MB file takes 18 minutes, 59 seconds to copy over the satellite link alone. With the Riverbed gear turned on that drops to 4 minutes 50 seconds. Similar tests for an 18.4MB file drops the transfer time from 17 minutes, 20 seconds, to 3 minutes, 50 seconds. Caching bit patterns at either end of the link was not applied during these tests, but would reduce times further, the cruise line says.
Meanwhile, Crystal Cruises opted for F5 gear that sits on the land end of ship-to-Internet connections because the company is reluctant to put more gear on ships than is absolutely necessary. "If I can in any way avoid putting equipment out there that has the possibility of breaking, I'll do it," says Bjorn Andersson, manager of shipboard and network operations for Crystal Cruises.
"Everything you buy for a ship, you have to buy two of. We go down to Antarctica and we're seven days away from being in the civilised world. If a box breaks and we don't have a backup appliance out there, it could take a week or two weeks to get it fixed."
Crystal applies the device to all traffic from its ships. Crystal didn't have comparisons of the time it takes for transfers with and without acceleration, but did say F5's gear met a purchase agreement that guaranteed the device would improve the load time for Web pages by 50 per cent. The device exceeded the promised performance, Andersson says.
That improvement has resulted in a jump in Internet use, he says. Before the accelerator was installed, the satellite link was so slow that ship traffic never filled it. With the improved performance, the ships routinely burst above the 512kbit/s contracted for.
"We went from spiking 30 minutes per day to spiking between 14 and 17 hours per day - pretty much the hours when anybody was awake," Andersson says. The highest spikes reach 4Mbit/s per ship.
The company hasn't tried a two-ended acceleration product, but it may check one out if increasing Internet traffic chokes the current accelerator.
"I'm sure we can gain additional performance by doing something along those lines," Andersson says, "but just the significant improvement we've gotten so far and how it helped us utilise the satellite, we don't have the need now for a two-ended device."