Tsunamis prompt interest in 'Net alerts

Imagine this scenario: Minutes before the recent Indian Ocean tsunami crashes into Sri Lanka or Thailand, the cell phones of people lying on the beaches there start to ring and a short text message issues a warning to flee to higher ground.

Could a communications system like this have saved lives? Is it possible to build such a system by tapping GSM, a set of standards used globally by wireless service providers? These are some of the questions that the Internet engineering community is asking itself in light of the recent tragedy.

"If you want to get people off the beach, you could send a [Short Message Service] to every cell phone that is active in a certain cell," says Fred Baker, a Cisco fellow who has expertise in Internet-based emergency communications. "You would know what cell phones were active in a particular cell near the coastline. You'd be able to target a particular geographic region by basing it on the GSM service."

Baker and other members of the IETF have been working for several years to create methods for prioritizing emergency communications over the Internet. The IETF is considering expanding this work in response to the devastating tsunamis.

"Distributed robust networks like the Internet provide a wonderful opportunity to spread information quickly and to a wide audience, thus assisting in disaster recovery," says Kimberly King, co-chair of the IETF's Internet Emergency Preparedness (IEPREP) working group and a principal network engineer at Science Applications International.

King says the Internet can help in all types of emergency communications - between the public and governmental authorities, from one governmental authority to another, and between members of the public trying to reach each other. "It is clear the Internet has much to offer each of these scenarios," she says.

However, the Internet has one major drawback when it comes to emergency communications: It's a best-effort communications system, so there's no guarantee that an important message will be received in a particular time frame. That's what the IETF is trying to fix with its ongoing development effort.

"With the tsunami situation, you would want an e-mail or instant message to go from the warning center to the right place and get there in a stated amount of time," Baker says. "The message must be known to be coming from an authenticated user, and it must be flagged as an important message that needs to get through in a certain amount of time. If the message wasn't able to be delivered in the stated amount of time, it needs to bounce back. That's the kind of capability we're talking about."

In contrast, the public switched telephone network (PSTN) can prioritize emergency communications for applications such as the U.S. Government Emergency Telecommunications Service (GETS), which is used in the aftermath of terrorist attacks, hurricanes and other natural disasters. With GETS, bandwidth is reserved for emergency calls, and users also can schedule calls to guarantee they go through.

The U.S. military also has special telephone systems that support pre-emption to make sure important calls - such as from the commander in chief - are connected regardless of other traffic on the system. Neither pre-emption nor prioritization of voice calls is possible over the Internet today using standard protocols.

"Today's VoIP services generally don't signal for bandwidth. They're fairly limited in their knowledge of the network," Baker says. "If we're going to do anything like call scheduling or call pre-emption in the Internet, we need a whole lot more intelligence in the network to make that happen."