Bitcoin's 'nervous system' gets an upgrade, FIBRE communication network abandons TCP protocol prone to data loss and uses UDP instead

A long-running effort to improve the propagation time of bitcoin transaction blocks has received an upgrade.

Since the launch of Bitcoin, a range of services or solutions have emerged to meet the needs of those using digital currencies. These include: exchanges that allow the buying and selling of Bitcoin to and from fiat currencies; mining pools that have emerged as miners seek to group together for greater profits; and new types of wallets that offer better functionality and security.

However, some requirements of distributed networks are not easy to observe.

As Bitcoin Core developer Greg Maxwell explains, Bitcoin Relay Network , the brainchild of Bitcoin Core contributor Matt Corallo, was proposed a few years ago as a way to spread bitcoin block data more quickly among miners (or those who process transactions).

“A few years ago, when blocks started to go above 250K, we kept seeing miners quickly consolidate into a few very popular pools,” Maxwell recalled. “One of the reasons for this was that the smaller pools were getting isolated.”

He added: “We seem to be rapidly developing a trend where there will eventually be only one mining pool.”

However, he said Corallo took action and developed the original Relay Network, providing a solution that Maxwell called “fundamentally improving block propagation speed.”

Bitcoin Relay Network eventually materialized into a network of nodes located in China, Europe, North America, Russia, and Southeast Asia. Each node is a strong Internet connection, which, in theory, acts as a railway for block data. The data is compressed and then transmitted via the Transmission Control Protocol (TCP) .

The system has been described as Bitcoin’s vascular or nervous system — a key component that transmits messages throughout the body. Now, an enhanced successor has been released.

Enter FIBRE

Corallo recently launched the Fast Internet Bitcoin Fast Internet Bitcoin Relay Engine Engine (FIBRE), which aims to build a more powerful version of Bitcoin Relay Network .

The idea is that by improving the speed at which information is propagated, miners can reduce the number of orphan blocks, or blocks of transactions that are rejected by the network.

Corallo, who ran the original Fibre network and designed its new version, said the scheme also helps increase the cost of ‘selfish mining’ and reduce the number of empty blocks generated through SPV mining.

But according to Corallo, the existing distribution network began to show its 'outdated' side last year, prompting work on the new software in the past few months.

"Over the past few years, I've found, after careful testing, that you can't get the kind of low-latency relay you want with any form of TCP," Corallo said. "A few months ago, I finally built a new fast relay protocol from scratch, creating Compact Block as the foundation and an early version of FIBRE at the same time."

Corallo explained that the current problem is that networks functioning over TCP are prone to data loss, which would require additional processing and therefore increase the time it takes for blocks to propagate.

He introduced FIBRE in his blog post, With TCP, packets can be lost over time.

"The sender will then retransmit the lost packets, allowing the receiver to (potentially) reconstruct the original transmission," he wrote.

He explained that these extra round trips ultimately caused spikes in propagation times for the original Relay Network.

FIBRE Upgrade

To sidestep the latency issue -- the time it takes for a packet of data to get from one point to another (in this case, from one node to another), Corallo said he chose another protocol -- the User Datagram Protocol Datagram Protocol (UDP) .

“Instead of using TCP to send the data needed to deliver a block, and relying on full round trips to detect and resend lost packets, FIBRE uses UDP to send the data, with additional forward error correction (FEC) data (i.e., data that allows you to reconstruct the entire transmission even if some was lost),” he said.

Maxwell calls FEC 'a bit of technological magic'.

FIBRE also includes BIP152, a 'compressed block' protocol designed to reduce the bandwidth used when block data moves between nodes.

“That way, even if some pieces are missing, the block can still be received quickly and without the need for back and forth communication,” Maxwell explained. “It also retains its speed even if the block doesn’t look like it’s in the receiver mempool.” Network Impact

Yet for all its enhancements, perhaps FIBRE’s most ambitious goal is to work toward getting more networks run by people around the world.

Initially, maintenance of the network was hosted by Corallo himself, which meant that the operation of the network - like all Bitcoin nodes - depended on the ability to maintain the network.

Although FIBRE's code is freely available, Corallo said he doesn't have the capacity to support additional networks. Ultimately, the success of a network (or system of networks) arguably depends on getting more people to actually run them.

FIBRE seeks to change this dynamic. The software is designed as an add-on to Bitcoin Core, providing a way for more people to get their hands on the code and potentially launch their own distributed networks.

According to Corallo, he is working to encourage other parties to build their own FIBRE-based dissemination networks — an effort he said needs to remain decentralized.

Corallo also published a guide to creating a FIBRE network.

In the meantime, he said, new groups are now interested in setting up the dissemination system, and he said that for now, more cautiously optimistic users will help the cause grow.