Latency is a pain, and these researchers say they have the cure
SUMMARY: An EU-funded research project aims to re-engineer the TCP protocol, as well as the way routers work – and all without the need to replace expensive internet infrastructure.
There are two main things that can cause a real-time web service to be not-so-real-time: insufficient bandwidth and excessive latency. Bandwidth is an ISP issue, but latency — the time it takes for your computer to contact a server and/or get a response — is largely down to the way the internet is engineered.
So a team of researchers from around Europe, with some help from the European Commission, Alcatel-Lucent and BT, is aiming to revise a standard data-transport protocol to effectively re-engineer how the internet runs — without the need for pricey new equipment.
It’s a tall order, but they’re deadly serious. And from the vendor side, it’s not hard to see why: Alcatel-Lucent wants to slash latency for better videoconferencing, and BT wants to do the same in order to improve its Radianz Cloud platform, which serves the very time-sensitive financial services industry.
The project is called Reducing Internet Transport Latency (RITE). It quietly kicked off last November but the University of Aberdeen, where some of the researchers are based, has only just started making noise about it — largely because the researchers are about to set off for an Internet Engineering Task Force (IETF) meeting in Florida next month to show off what they’re up to.
“It’s a problem we all notice when you’re using a program like Skype. If anyone else in the house is watching a video at the same time, your video connection becomes jerky and often crashes. This affects gamers who want to play online in real time and companies doing stock training – both end up buying special and expensive internet connections to make these work, but often it’s not more bandwidth that’s needed to go faster – it’s less delay.
We think we can reduce this delay by making a set of small but important changes to the way computers and the network process the internet data.”
So, what sorts of changes are we talking about? Fairhurst told me on Thursday that there are two main strands to the RITE project’s work: revising the core Transmission Control Protocol (TCP, a.k.a the flipside to the Internet Protocol) and changing how network routers handle buffering.
“We’re trying to change TCP so that it works better with thin applications — applications that don’t send a huge amount of data and aren’t really interactive, like media streaming and conference calls,” he said. “We would make a small change to the timer mechanism so that you can recover data when you send a burst and lose part of it — it can take quite a lot of time to recover one lost packet — and we also have to do something to the way the congestion window works.
On the other side, to make this work effectively you have to change the way the routers behave as well. People know routers have lots of memory in them, but TCP tends to fill up all the buffers inside. We’re going to make recommendations on how to avoid buffer blocks — this is more directed at operators than people building PC software, but these things have to be done at the same time.”
Fairhurst noted that the TCP revisions would be piloted in Linux. After those Linux patches have been rolled out over the next year, the RITE researchers will try to get the standards community to do its thing and then “hopefully convince Microsoft, Apple and everyone else” to incorporate the changes into their applications. Google, which has developed the SPDY (pronounced “speedy”) protocol for reducing load time, has already shown interest, he claimed.
Apart from better videoconferencing and faster trading platforms, Fairhurst also suggested that success could “make the internet available to a whole new raft of applications,” such as proper virtual reality.
“It’s a small fix that really came from the gaming community originally,” he added. “Gamers really hate delay.”
Apart from the University of Aberdeen (Scotland), other research facilities involved in RITE include Simula Research Labs (Norway), the University of Oslo (Norway), Karlstad University (Sweden) and the Institut Mines-Telecom (France). The consortium has received just over €3.5 million ($4.7 million) from the European Commission.
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Why latency suddenly matters more than ever
For most of the internet’s history, bandwidth was king. Early web pages were static, email was asynchronous, and streaming video was a distant dream. But the rise of interactive, real-time applications has turned latency into a critical performance metric. Whether it’s a trader executing a split-second transaction, a surgeon controlling a remote robot, or a teenager battling friends in an online shooter, the delay between action and response can make the difference between success and failure.
The problem is compounded by the fact that many users mistakenly believe they need more bandwidth to fix a sluggish connection. In reality, a typical household cable or fibre connection offers plenty of throughput for most tasks. The real bottleneck often lies in the time it takes for packets to traverse the network — a time governed by the protocols and buffering strategies designed decades ago for a very different internet.
Inside TCP’s congestion control: a double-edged sword
Transmission Control Protocol (TCP) is the workhorse of the internet, responsible for ensuring reliable delivery of data across networks. It does this through a series of mechanisms, including acknowledgements, retransmissions, and congestion control. Congestion control prevents network collapse by detecting packet loss and reducing the sending rate. However, this design has an unintended side effect: it can introduce significant latency when packets are lost or delayed.
One specific issue is the retransmission timeout (RTO). If a packet is lost, TCP waits for a period before resending it. That timer is typically conservative, often several hundred milliseconds, because the protocol designers wanted to avoid unnecessary retransmissions on networks with highly variable round-trip times. For a real-time application like a video call, a lost packet that takes 300 milliseconds to be retransmitted can cause a noticeable glitch or freeze.
The RITE project aims to modify this timer mechanism so that it recovers more quickly from packet loss in thin, interactive streams. By making the RTO more adaptive to the application’s needs, the researchers believe they can shave hundreds of milliseconds off recovery times without compromising network stability.
Bufferbloat: the hidden latency tax
Even if TCP were perfectly tuned, another source of latency lurks inside network routers: bufferbloat. Routers traditionally maintain large buffers to absorb bursts of traffic and avoid dropping packets when congestion occurs. While this seems sensible, it can backfire. Large buffers encourage TCP to keep increasing its sending rate until the buffer fills, at which point every packet experiences a long queueing delay. The result is a network that feels slow even when throughput is high.
RITE proposes explicit recommendations for router operators to manage buffering more intelligently. Techniques such as Active Queue Management (AQM) can drop or mark packets before buffers become full, signalling TCP to slow down early. This keeps queues short and latency low, while still allowing occasional bursts through. The challenge is that changing router behaviour requires cooperation from network operators, many of whom are hesitant to alter equipment without clear evidence of benefit.
From research patch to everyday protocol: a long road
The RITE team plans to first implement its TCP changes in the Linux kernel, a natural testing ground because of its open-source nature and widespread use in servers and networking equipment. Patches will be rolled out over the next year, allowing researchers to measure performance improvements under realistic conditions. If the results are promising, the next step is to bring the proposals to the Internet Engineering Task Force (IETF), the body that standardises internet protocols.
This is where the hard work begins. Standards processes are slow and contentious, and even small changes to a protocol as critical as TCP can take years to gain consensus. The project members are optimistic, however, pointing to Google’s success with SPDY—a precursor to HTTP/2—as evidence that latency-focused innovations can gain traction when major players see value. Google has already expressed interest in RITE’s work, and if a few influential companies adopt the changes, others may follow.
Beyond RITE: the broader fight against latency
RITE is not alone in its quest. Google’s SPDY protocol, released in 2009, reduced web page load times by multiplexing streams and compressing headers. More recently, Google has been developing QUIC, a transport protocol built on top of UDP that promises even lower latency for web applications. While RITE focuses on improving TCP itself, QUIC essentially bypasses TCP’s limitations by moving reliability and congestion control into the application layer.
The two approaches are not necessarily competing; they target different layers and use cases. RITE’s changes to TCP would benefit any application that relies on the protocol, from legacy systems to new services. QUIC, on the other hand, is primarily aimed at web browsing and HTTP/3. Ultimately, a combination of improved TCP, smarter buffers, and alternative protocols may be needed to achieve the latency reductions that emerging technologies demand.