Right now, as any smartphone owner knows, a phone or tablet will either use Wi-Fi or 4G or 3G—and never at the same time. So your streaming video may cut out because the network you were using dropped, even though there’s another signal available.
Multipath TCP could change this by divvying up those video bits across two or more networks. “Multipath” refers to using more than one wireless route, and TCP refers to the protocols used by most Internet traffic. Then, to use a simplified explanation—all “odd” packets (units of data that make up an Internet transmission) get sent over Wi-Fi and “even” ones over 4G. Then these “odd” and “even” packets get woven back, zipper-like, on the phone.
But in practice, it’s not that simple. The problems start with the fact that data-transmission takes longer from a cell tower than it does from a Wi-Fi router. Throw satellite streams in and the transmission delays are even longer.
Multipath TCP makes up for this by tweaking transmission speeds. But matters get more complicated if you are moving around, meaning those timings are always changing—and worse still, if some packets drop out. When those things happen, the computation required for multipath processing can get so complex that it actually slows down the overall speeds, says Medard.
Apple may be using the technology to simply enable Siri to switch back and forth between them without user intervention, so it can avoid having to retransmit your spoken request, a source of delays.
There is a technology that helps solve the remaining problems with multipath TCP. It is called “network coding”—an extra tweak atop multipath TCP. Network coding algorithmically combines packets in elegant ways. Then multiple packets can be turned into a single number that’s a function of the ones making it up. “You code within flows for redundancy,” Medard says. “Then you don’t have to be managing between them like crazy.”
It was this version that, when tested by Cloud and colleagues at the Hamilton Institute, part of the National University of Ireland in Maynooth, Ireland, provided up to 10 times better performance on a single network path, by repairing dropped packets on a single connection.
Measurements done at the University of California, Los Angeles, suggested how network coding could turbocharge multipath TCP. In findings presented in June, Medard and several university collaborators measured actual packet losses and other conditions around a Westwood, California, campus from three wireless sources: Wi-Fi transmitters, cellular towers, and Iridium satellites. They concluded the technology could provide a similar benefit when used on multiple paths, with a potential tenfold increase per path.
Code on Technolgies
Network Coding is a coding technique used to improve network throughput, efficiency, scalability and resilience to attacks and eavesdropping. Instead of relaying packets of information, Network Coding uses the computational capabilities within network nodes to take several packets and combine them together for transmission or storage. This technique improves information flow and storage in networks by making coded packets more versatile.
Code On licenses a family of coding technologies based on Random Linear Network Coding (RLNC), a proprietary algorithm that enables Network Coding. It is not an operating entity but rather prefers to work with new and established companies to develop Network Coding optimized products and services. Professional consulting services and training are a key part to Code On’s product offering.
Code On uses a proprietary algorithm, Random Linear Network Coding (RLNC), to enable a range of Network Coding applications for networks, storage and mobility applications. The key differences between RLNC and other, traditional codes are captured in the below table.
SOURCES – Technology Review, Code On Technologies