Ethereum London Upgrade Overview
Source: Ethereum Cat Herders; Author: Tim Beiko
Over the past few months, Ethereum core developers have been working on a London network upgrade. It is an upgrade following the Berlin upgrade, which was forked from the mainnet in April. Although the upgrade block height of each network has not yet been determined, the EIP included in the London upgrade has been determined. According to the upgrade specification, the EIP is as follows:
➤ EIP-1559: Eth1.0 fee market changes
➤ EIP-3198: BASEFEE opcode
➤ EIP-3529: Reduce gas return
➤ EIP-3541: Reject new addresses starting with 0xEF bytes
➤ EIP-3554: Difficulty bomb delayed until December 2021
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EIP-1559: Eth1.0 fee market changes
EIP-1559 is one of the most anticipated changes in the history of Ethereum, and it is also the EIP that brought the biggest change in the London upgrade. This EIP will introduce a "base fee" in the network block", which keeps track of gas prices from transactions the network will accept based on block space demand. This means that wallets and users will be able to more easily predict the price of their transactions. In addition, EIP-1559 has added a transaction type where users can specify the maximum amount they are willing to pay. When they send this maximum fee to the miners, they will get the maximum fee minus the sum of the base fee and the miner’s tip. Refund for difference. Finally, this EIP will also result in some transaction fees being burned, which is considered by most of the community to be an important improvement in the economics of the Ethereum network.
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EIP-3198: BASEFEE opcode
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EIP-3529: Reduce gas return
Another breaking change introduced in London is the removal of the gas refund for opcode SELFDESTRUCT and the reduction of gas refund for opcode SSTORE. Although the original intention of setting up the return is to encourage developers to clear the state when possible, the reality is that this leads to the appearance of Gas Token, which increases the size of the state. Using these returned gas, Gas Token can fill up the state when the gas price is low, and then get refunded for executing these transactions when the gas price rises.
In addition, gas return will also cause changes in block execution time. Before the London upgrade, up to 50% of the returned gas could be used for further calculations in the same block. That is to say, in practice, the largest block size can reach 1.5 times the gas limit. EIP-2539 put"Execute gas return"first level title
EIP-3541: Reject new addresses starting with 0xEF bytes
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EIP-3554: 2021 difficulty bomb delayed until December 2021
EIP-3554 Delayed Difficulty Bomb, also known as Ice Age. The difficulty bomb or ice age is a mechanism introduced by Ethereum to "freeze" mining as the network transitions to proof-of-stake. Since the proof-of-stake transition isn’t ready yet, we need to delay the bomb’s “explosion”. This has been done three times in the past: in Metropolis (EIP-649), Constantinople (EIP-1234) and Muir Glacier (EIP-2384).
While previous delays have been quite long, this time the core developers opted for a shorter delay, pushing the difficulty bomb to December 2021. At that point, the network will either undergo a transition to proof-of-stake or another network upgrade.
That concludes the entire list of changes incorporated into the London upgrade. An updated block height for the testnet and associated client releases will be posted on the Ethereum Foundation blog shortly.
