New technique could boost internet speeds tenfold
Researchers at Aalborg University, MIT and Caltech have developed a new
mathematically-based technique that can boost internet data speeds by up
to 10 times, by making the nodes of a network much smarter and more
adaptable. The advance also vastly improves the security of data
transmissions, and could find its way into 5G mobile networks, satellite
communications and the Internet of Things.
The problem with TCP/IP
Data is sent over the internet in "packets," or small chunks of
digital information. The exact format of the packets and the procedure
for delivering them to their destination is described by a suite of
protocols known as TCP/IP, or the internet protocol suite, designed in
the early 70s.
Back when it was conceived, the internet protocol suite was a
tremendous leap forward that revolutionized our paradigm for
transmitting digital information. Remarkably, 40 years on, it still
forms the backbone of the internet. However, despite all its merits, few
would say that it is particularly efficient, secure or flexible.
For instance, in order for a TCP data transmission to be successful,
the recipient needs to collect the packets in the exact order in which
they were sent over. If even a single packet is lost for any reason, the
protocol interprets this as a sign that the network is congested – the
transmission speed is immediately halved, and from there it attempts to
rise again only very slowly. This is ideal in some situations and
terribly inefficient in others. The issue is that the protocol doesn't
have the intelligence to know what the right thing to do is.
Also, although the packets could take a theoretically infinite number
of paths to travel between point A and point B in a network, it turns
out that data in a TCP connection always travels along the same path –
which makes it quite easy for an eavesdropper to spy on your communications.
Network coding – the solution?
An interesting proposal that might offer the solution to these
problems is so-called network coding, which aims to make each node in
the network much smarter that it currently is. In TCP/IP, the nodes of
the network are just simple switches that can only store data packets
and then forward them to the next node along their predetermined route;
by contrast, in network coding each node can elaborate packets as
needed, for instance by re-routing or re-encoding them.
Adding intelligence at the node level may be a truly disruptive
change, because it allows for unparalleled flexibility in the way
information is handled. For instance, it can take advantage of
multipath TCP
(implemented in iOS 7) and, on top of it, add an encoding mechanism
that further increases security and speed, or even enable data storage
right within the nodes of the network.
Researchers Morten Videb and Janus Heide (Photo: Aalborg University)
In a recent study, a team of researchers from Aalborg University
(Denmark), MIT and Caltech have built an implementation of just such a
protocol, displaying some impressive speed gains. In a demo, a four
minute-long mobile video was downloaded five times faster than with the
state of the art technology, and was then streamed without
interruptions.
"In experiments with our network coding of Internet traffic,
equipment manufacturers experienced speeds that are five to 10 times
faster than usual. And this technology can be used in satellite
communication, mobile communication and regular internet communication
from computers," says Prof. Frank Fitzek, who led the study.
How it works
Whether the contents of a packet are part of a YouTube video, a text
or a song, they are nonetheless encoded by a string of zeros and ones,
which can also be seen as a number in binary format.
In TCP/IP, the nodes of a network treat data packets individually by
simply storing their content and relaying it to the next node. But in
the protocol developed by Fitzek and colleagues, the content of the
packet is seen as an actual number, and packets are processed in chunks.
Each node builds a set of
linear equations, using both the numbers extracted from the content of the packets and a set of randomly generated coefficients.
Each linear equation forms a "coded packet" where the coefficients
are stored inside the coded packet's header, and the unknown variables
are the actual contents of the packets, treated as a number. In other
words, each coded packet contains partial information on several
"standard" packets at once, but multiplied by different coefficients.
As you might remember from high school math, you need N linear
equations to solve for N unknown variables. Because each coded packet
contains a single equation, this means that the recipient will need N
packets (with different coefficients) before it can decode the data.
The
system is much safer than the current Internet protocols, because an
eavesdropper would need to intercept all the packets to decode the
information (Image: Franz Fitzek)
But why go to the trouble of complicating things so much? The answer
is that now, unlike with TCP/IP, the recipient doesn't need to receive
packets in order. In fact, the order in which packets are received
becomes completely irrelevant. All that matters is that the recipient
obtains N coded packets, all with different coefficients, so it can
solve the equations and obtain the original data.
This flexibility in the order means that the whole system is much
more efficient, because all the packets are interchangeable. A lost
packet is no longer cause for severe transmission delays as in TCP/IP.
And because the order doesn't matter, the packets can now travel
along different paths through the network. This also increases security,
because it becomes nearly impossible for anyone to intercept the
communication by tapping into a single line.
What's next?
The technology could find application in 5G telecommunications, the
Internet of Things, and software-defined networks. Moreover, the
intelligence of the network also opens up the possibility of vastly
distributed storage solutions directly within the network.
"I think the technology will be integrated in most products because
it has some crucial and necessary functions," says Fitzek. "The only
thing that can stop the development is patents. Previously, individual
companies had a solid grip on patents for coding. But our approach is to
make it as accessible as possible."
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