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Network Congestion In Blockchain

Last Updated May 10, 2024 2:15 PM
Andrew Kamsky
Last Updated May 10, 2024 2:15 PM

Key Takeaways

  • Network congestion occurs when more data packets exist than a network can handle, leading to a delay in processing time and higher transaction fees.
  • Bitcoin’s 1MB block size and 10-minute intervals lead to congestion, affecting transaction speed and costs.
  • Increased transaction activity from market events tends to be one catalyst that overwhelms Bitcoin’s blockchain capacity, resulting in network delays and fee spikes.
  • Layer-2 solutions like Lightning Network and sidechains like Liquid help reduce congestion by handling transactions off the main layer-1 blockchain.

Network congestion happens when a network is overwhelmed by more data packets than it can handle. A data packet is a structured data unit sent over a packet-switched network containing both the payload and necessary routing information. 

This buildup of data traffic stems from excessive communication and data requests made on a network that lacks sufficient bandwidth to support them.

Bitcoin’s Design Vs. Network Congestion

Bitcoin has a unique design that uses a blockchain to record transactions in blocks every ten minutes. Each block has a fixed size of 1 MB, which restricts the number of transactions each block can hold to 1 MB. 

The 10-minute timing is designed to balance speed and security. Still, it can lead to delays during high transaction periods—a backlog forms when transaction volumes exceed block capacity, leading to network congestion. The congestion results in slower transaction confirmations and increased transaction fees as users making the transfers will bid higher to prioritize transactions earlier. 

Causes Of Bitcoin Network Congestion

Spikes In Transactions

Network congestion is when there is an increase in transaction activity, driven by significant market events or news that prompt users to actively trade or adjust Bitcoin holdings. This increased activity strains the network, exceeding the block capacity and leads to delays.

Limited Block Size

The 1MB block size limit directly contributes to network congestion capping the number of transactions that can be processed every 10 minutes. The restriction, initially intended as a security measure, serves as a bottleneck that slows transaction processing during peak times.

Fee Market

The competitive nature of transaction fees becomes more apparent during periods of network congestion on Layer-1. Here users will end up paying higher fees to skip the que, which effectively speeds up those individual transactions potentially sidelining others who are unable or unwilling to pay increased transaction fee costs.

Consequences Of Network Congestion

Below are some consequences of seeing network congestion on the Bitcoin blockchain:

Delayed Transactions 

Network congestion leads to delays in transaction confirmations, extending from the intended 10-minute intervals to hours or days. The delays undermine Bitcoin’s effectiveness as a reliable payment method.

Increased Fees

During periods of network congestion the transaction fees increase, the increase in fees make small transactions economically impractical and reduce Bitcoin’s use case as a payment rail for everyday purchases.

Reduced Network Usability

High fees and slow confirmation times tend to reduce the user experience. This is because the slow network processing times may increase a sense of doubt when waiting for confirmation of a transaction on the network.

Potential Solutions To Address Blockchain Network Congestion

To reduce blockchain network congestion there are several solutions that have been proposed:

Layer-2 Scaling Solutions

  • Lightning Network: The lightning network involves the creation of off-chain payment channels to enable faster, low-fee transactions. The layer 2 solution allows users to conduct numerous transactions outside of the main Bitcoin blockchain, with the benefit of reducing the load on the network.
  • Sidechains: Are separate blockchains pegged to Bitcoin that operate with different rules to enable for higher transaction throughput. Transactions that can be processed on these sidechains before being reconciled with the main blockchain, easing congestion.
  • Liquid Sidechain to Bitcoin: Liquid was designed to provide faster transactions and privacy whilst operating as a secondary layer on top of the Bitcoin blockchain. Liquid allows users to lock up Bitcoin into the Liquid sidechain, resulting in quicker and more secure transactions via higher throughput compared to the main network.

On-Chain Scaling Solutions

  • Block Size Increases: Increasing the block size is a straightforward approach to fit more transactions into a single block. However, this method is controversial as it could lead to greater centralization since larger blocks might require more advanced hardware to process, potentially excluding smaller node operators.
  • SegWit (Segregated Witness): The SegWit upgrade changes the way data is stored in blocks, separating the transaction information from the signature data, increasing the block’s capacity to hold more transactions without altering the block size limit.
  • Schnorr Signatures: One important Bitcoin upgrade was Taproot, which introduced several enhancements, among them Schnorr signatures. Which allow for signatures to be aggregated into a single signature, Schnorr Signatures reduce the data needed per transaction, increasing throughput on the blockchain.


To effectively manage network congestion in blockchain, particularly in Bitcoin, a combination of Layer 2 and on-chain scaling solutions have been adopted. Layer 2 solutions like the Lightning Network and sidechains such as Liquid have helped reduce pressure on layer-1 by handling transactions off the main chain which has reduced network congestion. 

On-chain solutions, including block size increases and protocol optimizations like SegWit and Schnorr Signatures, also have helped scale Bitcoin to a healthy capacity. Together, these strategies have improved transaction throughput, reduced latency, and maintain Bitcoin’s decentralized nature, addressing both current limitations and future demands.


Why is the Bitcoin difficulty set to 10 minutes per block?

The 10-minute block time balances security and efficiency by preventing chain forks and ensuring sufficient time for global network propagation.

Can Bitcoin run out of blocks?

No, Bitcoin cannot run out of blocks; the protocol allows for continuous block creation at predefined intervals indefinitely.

How is the Bitcoin block time kept stable at 10 minutes particularly given anyone can mine?

Bitcoin’s network adjusts the mining difficulty every 2016 blocks to maintain the average block time at around 10 minutes, regardless of total mining power.

What keeps the average block time at 10 minutes?

The mining difficulty adjustment, which occurs every 2016 blocks, ensures that the average block time remains close to 10 minutes despite fluctuations in mining power.

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