Homework on Stale Blocks

[Alex_Carr]

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

Two versions of the truth are propagated on the blockchain.

2. What is a stale block?
   A stale block is a block that is dropped by the network and the it’s transactions are sent back to the meme pool.

3. How do stale blocks occur?
   When two miners solve a block at the exact same time two blocks with the same versions of the truth are propagated on the network. Whichever block the next miner chooses to sync hash with will continue the chain and the other block will be dropped from the network. This is because the network will always choose the longest chain. The dropped blocks are known as stale blocks.

4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
   Incase the situation occurs when two miners solve a block at the same time the system is a global system and therefore needs time to physically travel and confirm which block it will be continuing with and which is a stale block.

[Kyle_V]

1. What happens in the bitcoin network when two miners solve a block at the same time?
   The nodes closest to that miner will use the miners block it’s closest to. Whichever block is selected by the next miner and mined the block with the most chains will be selected and added to the blockchain and the stale block will be readded to the mempool.
2. What is a stale block?
   A stale block was a competing chain that now has been rejected by the network and readded to the memepool.
3. How do stale blocks occur?
   When two miners solve the block at the same time whichever block is selected by the next miner and mined first will create a longer chain and will be selected into the network and the stale block dropped.
4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
   To ensure your transaction is not dropped and is accepted in the next block.

[samartrade]

1. When 2 miners solve the next block at the same time, both blocks get added, which results in creating 2 different sequences; it depends on the next miners getting which sequence to work with, the network waits for another 6 more confirmed blocks in a single sequence before the block sequence is confirmed to the blockchain. The confirmed blocks on the other sequence will be considered stale, and the transactions will move back to the mempool to be reprocessed.

2. A stale block is a confirmed block, but because it wasn’t propagated fast enough in the network, the next miners will work on other confirmed block sequence created by other miners. , blockchain will delete stale blocks, and the transactions will go back to mempool for reprocessing.

3. a stale block occurs when 2 miners solve the next block at the same time, and both blocks are added which creates a subsequence in the blockchain; it depends on how fast the new sequence is propagated to the nodes in the network and miners picking which sequence to confirm the next blocks, after 6 confirmed blocks the blockchain determines the longest sequence and overwrite the other one. The blocks that blockchain deletes are called staled blocks.

4. The more time we wait between blocks, the more time we have to propagate the new blocks to the nodes, minimizing the stale blocks.

[Jackthelad]

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, they propagate to the nearest nodes on the network, temporarily creating two chains, whichever block has its hash value used in the solving of the next block, and becomes part of the longer chain, will be seen as the true block, and the second block will have it’s Tx’s returned to the mempool. Typically 6 new blocks are required to be added to the chain of either block before one can be said to be ‘truer’ than the other.

What is a stale block?
A stale block is one that was in the blockchain at one time, but which was dropped due to it being part of a shorter chain following a temporary split in the blockchain due to a duel confirmation of a new block.

How do stale blocks occur?
Stale blocks occur when a bifurcation occurs in the blockchain due to the simultaneous solving of a block by different miners, and the propagation of these different blocks to proximal nodes, depending on which block is utilised for further mining ie which block has its hash value incorporated into the next block, and how low the target number is in each chain, one chain will become dominant, the blocks within the other chain are thus stale, as they no longer have their hash values incorporated downstream in the chain, their Tx’s are returned to the mempool for reconfirmation.

Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
This is important to ensure that the transaction is within a block which is receiving consensus, and is being further incorporated within the blockchain, it is a safeguard against it being returned to the mempool as a result of being within a stale block.

[Roger_Jaanhold]

1. Both of these blocks will be added to blockchain, until one of these blocks get mined by others and becomes primary, while the other one gets dropped.
2. Stale block is a dropped block which were added to blockchain for a short period but got overrided with other block which got adopted faster.
3. Stale blocks occur when two miners find correct nonce for same block which is under the target and one of these blocks get to go on blockchain, gets adopted faster from other miners and other one gets dropped, stale block.
4. To confirm that your block doesnt get dropped or classified as stale block which will not be on main blockchain

[PetraH]

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

It needs to be wait for another block. That one which will follow with new block will stay in blockchain the other one will be dropped.

2)What is a stale block?
The one which was in a blockchain but was dropped because was in a shorter version of blockchain.

3)How do stale blocks occur?
They were in shorter version of blockchain where we were waiting for 6x confirmation

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

Then we make sure that the block will not dropped

[Osbiju]

1- It begins a competition, the longest blockchain in PoW will win, the other will be dropped from the network (orphaned/stale).
2- Stale block (orphaned) is called when the valid block is dropped and transactions goes to mempool.
3- It occurs when it appears two versions of truth (blocks), they’re propagated in the network and keeps the one that resolves with a longer chain.
4- 6 confirmations is needed to be a successful transaction, because it can be the possibility that your transaction is in a block that can be dropped.

[Dawton]

1. When 2 miners solve a block at the same time, the network temporarily splits until one chain is established by the next block being created make one chain longer. The other block is then dropped.

2. A stale block is a block that has been dropped from the network. It is a valid block but the blockchain went off in a different direction.

3. As in question one stale block occurs when two miners find a valid nonce number at the same time creating two valid block.

4. It is important to wait for more than one block to be confirmed because if the block is dropped then it will re enter the mempool for re confirmation. But if we didn’t wait the transaction would of already gone through, then it would still be in the mempool if the block is dropped and could be confirmed again and make a duplicate transaction.

[eunice_salimao]

1. What happens in the bitcoin network when two miners solve a block at the same time?
   Both blocks will be appended to the blockchain but the longer Proof of work will remain in the blockchain and the other block (stale block) will go back to the mempool.
2. What is a stale block?
   It is a block that was once in the blockchain but got transferred to the mempool because there’s a version of the blockchain that’s longer.
3. How do stale blocks occur?
   When there are 2 blocks that get solved at the same time and appended to the blockchain and one of them gets dropped and transferred to the mempool because there’s a version of the blockchain that’s longer.
4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
   It’s best practice to wait for 6 blocks to confirm transaction to avoid stale block from occurring.

[VBence99]

1.) There will be two blocks for a short period of time until another new block gets created based on one of the two. Then the other one gets dropped.

2.) A stale block is a block that has been dropped and its TXs have been taken back to the mempool.

3.) A stale block occurs when a block gets dropped from the blockchain.

4.) Even though a block is confirmed, it may happen, that at some point in the near future that the block containing your TX gets dropped. However, if you wait until 6 new blocks are generated after your TX, it is very unlikely that your block will get dropped.

[Hallow]

1. What happens in the bitcoin network when two miners solve a block at the same time?
   If they solve a block at the same time, two versions of the blockchain will exist in their specific nodes that they propagated their new block.
2. What is a stale block?
   A stable block is a block that was on the blockchain but then got dropped from the blockchain.
3. How do stale blocks occur?
   Stale blocks occurs when a longer blockchain gets propagated to nodes that have a shorter one and as there is only one version of the truth, the longer chain gets accepted and the short one rejected.
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 in order to make sure that the new block continues to be in the longer chain and not get dropped in the next iterations.

[Juan_araujo]

1. What happens in the bitcoin network when two miners solve a block at the same time?
The blockchain will prioritize the longest network due the PoW

2. What is a stale block?
A stale block is a block that competed with other block and because it didn’t reach the target was thrown back to the mempool

3. How do stale blocks occur?

it happens when 2 blocks are competing and a 3rd block is added to one of the two blocks, this will make a longer network and the other one will be transferred 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 reduce the possibilities of the block be dropped again to the mempool it usually needs to be confirmed 6 times before getting added to the blockchain

[Zaqoy]

1. What happens in the bitcoin network when two miners solve a block at the same time?
   There will be two versions of the blockchain that miners will race to keep their version from going stale.

2. What is a stale block?
   A stale block is a block that has its transactions put back in the mempool in favor of a blockchain with more proof of work.

3. How do stale blocks occur?
   If miners complete a block at the same time, each chain will keep expanding until one has more proof of work and becomes excepted by the network as the truth. The blocks on the other blockchains will become stale.

4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
   To ensure that the block that contains your transaction does not go stale.

[akhilkm96]

Are incentives given to the stale blocks too?

If miners are grouped in an area, will that create a better chance for getting their blocks accepted?.., and would it depend on the latency of the medium in which information is propagated between the nodes?

[Gutto13]

1. A fork in the blockchain. Each of those miners will add their block to the blockchain and begin broadcasting their version of the new blockchain. As their blockchains gets propagated through the network it is possible for miners to add blocks to each of those two different versions of the blockchain. Ultimately, since the rule of the bitcoin blockchain is to choose the chain with the most PoW, one will have less and get phased out along with the blocks that were added at and after the fork. The transactions on these blocks will go back to the mempool.
2. A stale block is a block that has gotten dropped from the above scenario.
3. Mentioned in above example.
4. It is important because you don’t want your transaction to end up on one of these Stale blocks that get dropped from the blockchain. When this happens, there is no record of your transaction and you might get scammed out of a deal.

[TheBboyWannaBeDj]

1. The block created by both miners will be considered as valid, which will create two different version of truth. Then depending on which block the network decides to continue mining, one of the blocks will end being dropped, sending back the transactions to the mempool.

2. Blocks that were on the Blockchain but ended up being dropped, because there is another version of the Blockchain that is longer without those blocks in it.

3. When two miners create a different block approximately at the same time, and one of the blocks will eventually be rejected, becoming a stale block.

4. To make sure that your block doesn’t get dropped.

[rlrs13]

1. What happens in the bitcoin network when two miners solve a block at the same time?
   Only one miner will have that extra block that extends the length of the blockchain, meaning all other transactions are discarded and relocated in to the mempool.

2. What is a stale block?
   Stale blocks are blocks that were in the network at one point but didn’t make it to the next block so it was automatically dropped from the blockchain.

3. How do stale blocks occur?
   this occurs when two miners produce valid blocks at similar times but only one can propagate through the network fast enough to leave the other block stale or orphaned.

4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
   To confirm all transactions that links you to the blockchain.

[PapaCoins]

1. What happens in the bitcoin network when two miners solve a block at the same time?
   The network will pick the longest network from the next block that’s formed.

2. What is a stale block?
   Stale blocks are valid blocks that are dropped due to two miners solving a block a the same time.

3. How do stale blocks occur?
   When two miners are solving the same block but one of the blocks is dropped because the network will pick the longest chain.

4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
   This allows the network to update to ensure that the block is not dropped as an orphan or stale block.

[stg3o]

1. As two miners reaches the correct solutions for two blocks, propagates it at the same time and gets both blocks validated simultaneously. This now makes two versions of a valid blockchain but one is dropped as the next block gets appended to the blockchain. The network always chooses the longest chain with most PoW to continue adding future blocks.
2. The dropped block above is called stale or orphaned.
3. This is also how it occurs.
4. A tx is not really confirmed until 6 new blocks has been added to the chain. If it happens that your tx would be on a stale block, your tx will go back into the mempool.

[Alko89]

@akhilkm96

Are incentives given to the stale blocks too?

No because the block reward is part of the tx structure and gets dropped with the block.

@akhilkm96

If miners are grouped in an area, will that create a better chance for getting their blocks accepted?

Theoretically yes because it makes more miners mine on the block faster insuring it will remain on the blockchain.