Homework on Stale Blocks

[brunaveloso]

1. What happens in the bitcoin network when two miners solve a block at the same time?
   It might happen that we end up with two different versions of the blockchain.

2. What is a stale block?
   It is a block that is dropped out of the blockchain, even it being valid.

3. How do stale blocks occur?
   If two miners mined a block each at the same time, it might be that each block gets linked to the current version of the blockchain, without one acknowledging the existence of the other. So, after the information is in sync with the whole chain, one of the blocks is dropped (the one that is in the shorter version of the blockchain, since the longer version will always be the valid one).

4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
   Because this way there won’t be a chance for the block in which your transaction is placed to be dropped. If there are more confirmations - if there are more following blocks linked to the block in which your transaction is placed -, it basically means that your transaction is in a block that has no chance to be dropped (dropped block = stale/ orphaned block).

[TurtleFoot]

1.What happens in the bitcoin network when two miners solve a block at the same time?

When two miners solve a block at the same time a new miner will come into verify one of them the other block not verified will become stale and all transactions within that block will be sent to the mempool for later confirmations.

2.What is a stale block?

A stale block is a block that has been rejected or not verified.

3.How do stale blocks occur?

A stale block occurs when it ends up not having the longest chain therefore gets sent back to the mempool.

4.Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?

Its important to wait 10 min to help deal with stale blocks. Which is 6 blocks after that one block is confirmed so it gives time to sync with the network .

[aldrin]

1. What happens in the bitcoin network when two miners solve a block at the same time?
   **those will get propagated as a confirmed block; democratically the longer the chain of blocks would remain and the shortest would be discarded and send back to the mempool **
2. What is a stale block?
   a block with valid nonce and hash but discarded due that is the shortest
3. How do stale blocks occur?
   stale blocks occur when the network realized there are two ‘confirmed’ blocks; the shortest chain is consider and become stale block and will be send to mempool (unconfirmed) transactions
4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
   it is important to wait for at least 6 confirmations, so that the transaction is not staled, then discarded or invalid.

[DeanMacF]

1. At that moment there are two versions of the blockchain that are both true. Until one of the chains becomes longer. That chain will then be accepted as the true chain and the other block that was mind becomes a stale block.

2. A block that is rejected by the network as it exists on a shorter chain.

3. If two miners mine both mine a block at the same time, splitting the chain. The block that is on the shorter chain becomes a stale block and it is rejected by the network.

4. So that your transaction isn’t sent back to the mempool as a result of the block becoming stale.

[Hector_Rodriguez]

1. What happens in the bitcoin network when two miners solve a block at the same time?

A temporary fork is created , the network will continue to propagate until the longest chain is determined ( Proof of Work)

2. What is a stale block?

A Dropped Block , which no more blocks will be appended to. The stale blocks are considered invalid .

3. How do stale blocks occur?

These are blocks that were unsuccessful at creating the next chain( block) .

4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?

It is important to wait for a minimum of 6 confirmation in order to accept a block to the chain

[Maki]

@TurtleFoot

Its important to wait 10 min to help deal with stale blocks. Which is 6 blocks

6 confirmations takes approximately 1 hour.

[TurtleFoot]

Thank you for correcting

[daim]

@ivan

• What happens in the bitcoin network when two miners solve a block at the same time?
• What is a stale block?
• How do stale blocks occur?
• Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?

1, Both of their chains are propagated across the network until another block is mined which will produce a longer chain which will force the shorter chain to be dropped.
2. A stale block is a block that was accepted onto the chain but then dropped because another chain twas longer.
3. Stale blocks occur when another chain is confirmed forcing a shorter chain to be dropped. All the dropped blocks are considered stale.
4. Its important to wait for more than one block to be confirmed because this ensures that the transaction is not a part of a block that gets dropped

[Jenx4]

1. What happens in the bitcoin network when two miners solve a block at the same time?

The chains are propagated within the network. Then when a new miner joins and adds to one block chain with a new transaction the other blockchain will be dropped.

2. What is a stale block?

A stale block is a dropped block.

3. How do stale blocks occur?

Stale block occurs when two miners solve a block at the same time then a new transaction is added to one chain or the other and the block that is not added onto drops and becomes a stale block.

4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?

6 confirmations are best practice to ensure that the transaction does not become part of a block that has forked.

[Herb]

1. What happens in the bitcoin network when two miners solve a block at the same time?
   The two blocks are added to the blockchain for more miners to choose which block they want to add onto. The chain with the most POW will be the accepted blockchain and the other will be sent back to the mempool.

2. What is a stale block?
   A stale block is a valid block that was sent back to the mempool.

3. How do stale blocks occur?
   When two blocks are mined at the same time it creates a fork in the blockchain. The branch that is not propagated by more miners is called a stale block and is sent back to the mempool.

4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
   By waiting for more than 1 block to be confirmed we are assuring the network has chosen which chain to propagate and thus not have our transaction block sent back to the mempool as a stale block.

[Chris83]

1. There will be two versions of the blockchain that are both valid.
2. A stale block is a block that will be dropped, that is when you have two versions of the blockchain.
3. They occur when a new block is added to one of the two blocks that where added at the same time to the network.
4. To avoid the block being dropped as a stale block.

[ratzonchain]

1. What happens in the bitcoin network when two miners solve a block at the same time?
   -> both valid blocks can split into 2 chains.
2. What is a stale block?
   -> a block that was once in the blockchain but has been dropped because it was not a part of the longer chain.
3. How do stale blocks occur?
   -> it’s when the chain forks into 2 valid blocks. The block the miners continue to add to will become the accepted blockchain and the other block will be dropped sending all its tx fees back to the mempool.
4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
   -> to make sure your your transactions don’t get dropped.

[HAMMERTHOR]

1. What happens in the bitcoin network when two miners solve a block at the same time?

This creates a “two versions of truth” situation. Note that transactions in either block are different. There are now two different blockchains. We may call them green and red. The nodes closest to each of these two miners’ block will propagate their blocks. When a third miner adds his new block, say, blue block to the green blockchain, the green blockchain is longer and from a proof of work and difficulty of work perspective, the green block propagates, and the red block is removed and all its transactions are returned to the mempool. All will accept the green solution.

2. What is a stale block?

A stale block is a valid block that though successfully mined, is excluded from the longer or longest proof of work blockchain.

3. How do stale blocks occur?

They occur when a network splits into two competing blockchains and miners add blocks to one of them and it grows longer and so has a longer proof of work.

4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?

This is important and necessary, and it is recommended to wait for six blocks to be confirmed when sending or receiving transaction to ensure that one’s block is not dropped.

[Reinis.S]

1. They co exists till next block choose where to link. Then stays only that block with longest chain.

2. Stale block is dropped block.

3. Stale blocks occur when 2 miners mine block with the acceptable nonce, and they both have been added to blockchain till next block choose to witch he links.

4. So that transaction would not drop. It could happen if block is dropped by network.

[chris90]

1.the longest chain will win the other block becomes orphaned
2.a block that is orphaned due to solving the block at the same time and was shorter then the other chain
3.when two miners solve the same block at the same time, longest chain wins shorter chain becomes orphaned
4.to ensure your block doesn’t get dropped

[FelipeP]

1. What happens in the bitcoin network when two miners solve a block at the same time?
   That one of the 2 blocks will be dropped, it will not continue because other miners will be faster in adding new blocks to the chosen block, before you.
2. What is a stale block?
   A stale, or sometimes also called orphan block, is a block that is finally removed from the network because it is not confirmed by enough nodes, since another block took it’s place by being validated faster.
3. How do stale blocks occur?
   As previously mentioned.
4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
   You should actually wait for 6 blocks, in order to assure that your block has been added to the network, because it might become stale or orphan after only a few.

[lizano93cr]

1. one gets drop eventually

2. a dropped block

3. they get orphan, because a longer chain is created

4. to validate it gets written in rock

[LucLight]

1 two versions of the blockchain is then propagated

2/3 when one of theses 2 chain is finally chosen tobe the mane one the block from the other change are dropped and called stale

4 to be sure our transaction is not sitting in a stale block

[Tomaso_Cascioli]

1.) the longest blockchain wins and the other ones orphans will drop (lose)
2.) the shorter block (stale or orphan block)
3.) when the block is discarded because its not the longest blockchain.
4.) to be sure that the longest blockchain is choses in the world wide network which is decentralized.

[Serell]

1. Nodes closest each miner pick up respective solutions. Network must wait for a confirmation to settle consensus. The longest chain wins.

2. Stale blocks or orphan blocks are the blocks that were not in the longest chain. They are discarded and go back to the mempool.

3. Stale blocks occur when 2 miners mine a valid block approximately at the same time.

4. Because it greatly reduces the odds of becoming stale.