In Ethereum, when a node ‘broadcasts’ a transaction or block, what algorithm is used to broadcast that transaction or block to all the nodes? Also, how does this algorithm discover peers? What are some resources I could use to learn about this algorithm and its use in Ethereum?

Note: This is not the same question as mine. Mine is much more in-depth.

  • 1
    Try starting here: ÐΞV Technologies Commented Jun 27, 2018 at 23:40
  • Related: ethereum.stackexchange.com/questions/10140/…
    – eth
    Commented Jun 28, 2018 at 0:46
  • Ok, I understand how a peer to peer network is established from @eth’s answer; how are transactions and blocks routed? Is it just a simple ‘flood’ method, where the nodes broadcast to all the nodes they know, or is it more complicated?
    – Nicholas
    Commented Jun 28, 2018 at 11:56

1 Answer 1


There is no algorithm that propagates the transactions or blocks to the network, if you are looking to understand how the blockchain works please this medium post, it will explain the answer to you're question and more.


Hope this helps.

  • I honestly don’t know what you mean. I understand the blockchain very well, I just want to understand the peer to peer aspect. There has to be some way that transactions are sent to miners and blocks are sent to all nodes, because a ‘blockchain’ isn’t some ephermeal thing that does that all for you. It’s just a data structure, and without some way of connecting to other peers, there is no decentralization, value, network, etc.
    – Nicholas
    Commented Jun 28, 2018 at 11:41
  • What happens is when a machine downloads the go-ethereum software, then it becomes a node, and connects to other nodes nearby through accessing to the network instance which is usually something like instance=Geth/v1.8.2-stable/darwin-amd64/go1.10 once connected, if the node sends a transaction it is broadcasted across the server, the transaction is sent to the peers which the said node is connected to first (MAX IS USUALLY 25), then to the peers of the peers that received the transaction first and so on. The same propagation happens with blocks in the network.
    – conwise17
    Commented Jun 29, 2018 at 14:55
  • I learned through other research that the peers are discovered through Kadelima. So Kadelima is used to broadcast blocks too? How specifically does that modified version work (there must be some edit, because it would not be efficient to just lookup every node in the network in order to distribute a block).
    – Nicholas
    Commented Jul 4, 2018 at 0:06

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.