MIT shot! Researchers open "spider" routing solution to increase blockchain speed by 4 times

Industry partners, consortia and suppliers have been working hard to address issues of scale and efficiency by expanding blockchain-based cryptocurrency transactions.

If successful, digital currencies can compete with traditional banks and even make credit cards obsolete, because one's bank account and credit will be associated with the public and private key infrastructure that they, not the bank, will control.


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Despite the increasing adoption and use of cryptocurrencies, the ability to use blockchain for large-scale fast payments remains a challenge. To this end, researchers at the Massachusetts Institute of Technology (MIT) have developed a more efficient transaction routing scheme called "Spider", which they say can increase the speed of cryptocurrency transfers by four times. Researchers plan to present more detailed information about the technology at the USENIX Network System Design and Implementation Symposium to be held in late February.

The current cryptocurrency network allows only a small amount of data to be stored per block and takes several minutes to process each transaction. For example, the average throughput of the Bitcoin ledger is 3.3 to 7 transactions per second (TPS), and Ethereum only reaches 10 to 30 TPS. In comparison, Visa's network processes about 1,700 transactions (TPS) per second on average-even more during peak loads.

Although it is regarded as open and efficient because the transactions in the peer-to-peer distributed ledger technology can be seen in real time, blockchain performance issues are real. That's because every entry on the blockchain requires every node to process it or reach consensus.

Transactions outside the blockchain (known as a "layer 2" topology) can be bi-directionally processed, bypassing the inefficiencies of distributed ledgers, while still using its immutable properties to record completed transactions in a transparent manner.

Despite the emergence of scalable two-way payment channel networks (PCNs), such as Lightning Network and Raiden Network, completing payments on PCN is still challenging. Bidirectional PCNs are still facing "channel saturation" because the smart contract scripts that control them will automatically route transactions along the shortest path. result? Some escrow accounts run out faster than others.

Because current inefficient routing schemes often deplete users' account balances, users must keep a large amount of funds in each account or often rebalance their accounts on the blockchain.

PCN relies heavily on two-way joint accounts (both parties can receive and send money), so funds can be transferred between any users. Researchers say that user B can have a joint account with user A and can also link to user C separately. User A and C are not directly connected, but user A can send money to user C through the joint accounts of AB and BC.

Vibhaalakshmi Sivaraman, a graduate student at the Massachusetts Institute of Technology's Computer Science and Artificial Intelligence Laboratory (CSAIL), said in a statement:

"The shortest path routing can cause imbalances between accounts, draining the main payment channels and paralyzing the system. Allocating funds in a way that balances the two user funds of each joint account allows us to reuse the same Initial funding to support as many transactions as possible. "

Researchers also used an algorithm to monitor data center congestion to identify queuing delays for congested accounts, which helped control transaction rates.

"For example, User A sends a remittance to User C through User B in a long line. Receiver C sends a payment confirmation to sender A, and sends a message to sender A that represents the waiting time of the transaction on user B." Researcher Say. "If it is too long, user A routes fewer transactions through user B. As the queue time decreases, account A routes more transactions through B. In this way, Spider can ensure that the transaction rate is only by monitoring the queue It's balanced and as fast as possible. "

The Spider topology allows cryptocurrency network users to invest only a small portion of funds in each account associated with the network and can handle approximately four times the amount of "off-chain" transactions before rebalancing on-chain.

The Spider routing scheme "packages" transactions and uses a multipath transport protocol to achieve high-throughput routing in PCN. The researchers said in the research paper that packetization enables Spider to complete large transactions on low-capacity payment channels over time, and multipath congestion control protocols ensure balanced use of channels and fairness across traffic. .

In the end, the researchers said, the more balanced the routing of the PCN, the smaller the required capacity, that is, the higher the total amount of funds for all joint accounts.

"Network performance improvement techniques for MIT researchers are similar to packet switching commonly used in telecommunications systems and queue management used in many system / network management solutions to reduce network congestion and traffic in data centers and other data aggregation points, "Avivah Litan, vice president of research at Gartner.

Through extensive simulations, the researchers said that they demonstrated that Spider processed 25% of the funds required by traditional routing schemes and processed 95% of all transactions.

"Also, for every 10,000 transactions routed, only one on-chain transaction is needed to achieve full throughput with unbalanced demand."

Litan says:

"Researchers at the Massachusetts Institute of Technology (MIT) are ingeniously applying existing technologies that are commonly used to improve network performance to blockchain channel solutions that are designed to reduce the mainnet transaction volume and subsequent performance bottlenecks. There are no shortage of clever mathematicians and computer scientists at MIT, so it is no surprise that they are developing this innovative solution for blockchain transactions. "