A TeleGeography map showing global submarine Internet cables.

When Alan Gross was arrested in Cuba five years ago, he told authorities that he was in the country to distribute laptops, satellite phones, and Wi-Fi routers in the hopes of increasing Internet access across the island. Gross was released from prison Wednesday as the United States and Cuba moved to normalize relations.

In a remarkable shift, the Obama administration and the Castro government also agreed to a series of moves aimed at opening up Cuba to real, high-speed, Internet access. Cuba and the United States, the White House said Wednesday, have agreed to begin allowing communications devices and telecommunications services to move between the two countries.

Cuba has long been siloed to its own, isolated corner of the Internet, a product of both the country's poor, outdated communications infrastructure and the Cuban government's pointed choice to prevent the vast majority of its citizens from roaming freely across global networks.

According to the International Telecommunications Union, Internet penetration in Cuba this year stands at a rate of 25 percent. But, the pro-democracy group Freedom House points out, that figure requires an asterisk about the size of the Caribbean.

That's because much of that access is limited to a Cuba-only portion of the Internet that consists of a national e-mail system, pro-government Web sites, and only a handful of other services.

In fact, only about 5 percent of the Cuban population can get on the full global Internet, and only, often, through government institutions, high-end hotels, and black market access.

A submarine fiber-0ptic cable called ALBA-1 connecting Cuba and Venezuela quietly came to life in January of 2013. But while that cable would make it possible for more Cubans to have fast broadband access, it has in practice been little used.

In a recent Freedom House ranking of Internet freedom, Cuba earned an 84 on a scale of 1 to 100, placing it among the least-free countries in the world.

Whether the new U.S.-Cuba agreement means simply that it will be easier for Cubans to get online or whether they'll also be freer to move around once there remains to be seen. But perhaps nowhere on the planet has the fracturing of the global Internet been more real than it has been in Cuba. Wednesday's moves signal that perhaps, with the help of the United States, that will no longer be the case.

It won't be the U.S.'s first bid to massively expand broadband in Cuba. High-speed Internet access is already available at the U.S. military base at Guantanamo Bay.

Correction: Cuba's fiber-optic connection to Venezuela was activated in January of 2013, not May of that year. This piece has been updated to reflect that fact.