What is BIP 9, and why does it make soft forks easier to deploy?

Consensus and governance have been two major topics within the Bitcoin community over the past year. While changes to Bitcoin Core may seem minor to some, the factional disputes over certain proposals have caused major problems.

At the Blockchain Agenda conference in San Diego, bitcoin developer and Ciphrex CEO Eric Lombrozo gave a keynote address on potential options for bitcoin scaling.

He also expressed his views on the current problems with Bitcoin consensus rules, among which he mentioned the concepts of soft forks and hard forks, as well as a Bitcoin Improvement Proposal (BIP) that would eventually make it easier to deploy soft forks on the network.

The Problem with Changing Bitcoin’s Consensus Rules

Before discussing possible solutions, Lombrozo first talked about the current problems facing the Bitcoin network and the new consensus rules. Although the decentralization of Bitcoin is the value of its network, the lack of a main decision-maker makes the formulation of network rules a problem. Lombrozo explained:

“Whenever we want to change the consensus rules, this raises a serious problem because we don’t want to add new rules to the network. There is no central authority that can do this. We need a new way to make decisions that the network can accept when accepting this new rule, and we can also ensure that everyone will eventually agree to this rule.”

Hard Forks and Soft Forks

Next, Lombrozo touched on the topic of hard and soft forks. These forks occur when the rules of the network change and are currently the only option for upgrading the protocol.

“A soft fork happens when blocks that were valid in the past become invalid under the new rules,” Lombrozo said. “With this type of fork, if the majority of miners agree that the new rules are in effect, then that particular chain will overtake the other chain and it will become the main chain.”

Lombrozo said the hard fork process is a more difficult proposition:

“In the case of a hard fork, invalid blocks will become valid under the new rules, which will create a fork of the network that can last forever. Therefore, we will face a more difficult situation to solve its problems.”

Currently, a large part of the community wants to expand the Bitcoin block size through a hard fork. Bitcoin Classic is one of the alternative versions of Bitcoin that wants to achieve this change.

What is BIP 9?

In Lombrozo's view, the implementation of BIP 9 will make it easier to change the Bitcoin consensus rules. This proposal aims to allow multiple soft forks to be deployed at the same time. The principle is to change the block "version" field parsed by network nodes.

Lombrozo described BIP 9 during a presentation at the San Diego Blockchain Conference, saying:

“I’ve been busy working on BIP 9 recently, which is a mechanism that allows soft forks to be deployed more easily. It allows miners to signal when they are ready to enforce new rules, and it also allows you to have a parallel soft fork. So multiple features can be deployed at the same time without having to know which one will be activated first. It provides an early warning system so that old nodes can upgrade when they see that new rules are about to be activated.”

While soft forks may become easier to deploy in the near future, Lombrozo added: “Hard forks are still difficult.”

Original article: https://bitcoinmagazine.com/articles/bip-enabling-easier-changes-and-upgrades-to-bitcoin-1453929816
By Kyle Torpey
Compilation: Overnight porridge
Source (translation): Babbitt Information (http://www.8btc.com/bip-9)