At the initial stage of learning about cryptocurrencies and blockchain technology, many people often do not understand how networks work, why Bitcoin transactions take a long time to confirm, and how the network confirmation process works.

This model is simplified and intended only to understand the basics of the transaction confirmation process in blockchain networks.

This model is simplified and intended only to understand the basics of the transaction confirmation process in blockchain networks.

Brief Model:

• Passengers: Transactions
• Trains: New blocks appearing in the network
• Station: Network mempool
• Ticket Price: Network fee
• Controllers and Engineers: Miners
• Number of trains that left the station after the passenger boarded: Number of transaction confirmations

The entire blockchain network requires maintenance by miners who create new blocks. Imagine blocks as trains arriving at the station approximately every 10 minutes. However, the interval between train arrivals is always variable, and no one knows when the next one will arrive. Sometimes trains run every 2 minutes, and sometimes no new trains appear for an hour or longer.

When you or someone else wants to make a cryptocurrency transaction, a new transaction is created. You can imagine the transaction as a passenger wanting to get on a train. While the passenger-transaction waits at the station, it is in the network mempool, meaning it has not yet been included in the blockchain.

You can pay any amount, even zero, for the passenger-transaction fare, but miners prioritize passengers with higher fees. Everyone can see the fees set by other users. The transaction fee is the boarding fee for the train-block and is set before boarding. The set fee can only be changed by replacing the transaction itself.

The train-block has a limit on the number of passenger-transactions it can take. Each new train comes with a different number of cars and can take a different number of passengers. On average, a Bitcoin block can accommodate about 2500 passenger-transactions. If there are more passengers than the new train can take, long queues form. This can affect every network user.

When a passenger-transaction leaves the station-mempool and gets into the block-train, it receives its first network confirmation.

When a transaction gets its first confirmation, the user who sent or received it can usually use the funds. However, some places, such as exchanges or cryptocurrency exchangers, may require more confirmations for the secure transfer of funds.

Each new confirmation comes only with the appearance of new train-blocks that take new transactions from the mempool. If you need, for example, 5 confirmations, then after the transaction gets into one block, you need to wait for 4 more new blocks.

Common Issue:

Let’s consider a common problem that can occur with a transaction. Suppose there are few transactions in the mempool at some point, and the fare to board the block was high to get on the first available train. However, time passes, and no new blocks appear. Meanwhile, the number of transactions in the queue sharply increases, and new transactions begin to set higher fees to be included in the first block. As a result, the transaction can wait in the queue for several hours, which can cause dissatisfaction among the sender or receiver.

Sometimes you can rеplace a transaction, but this depends on the capabilities of your cryptocurrency wallet and available funds.