Given the overwhelming support for SegWit across the ecosystem of businesses and users, this seems reasonable to me.
On May 22, 2017 6:40:13 PM EDT, James Hilliard via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote: >I would like to propose an implementation that accomplishes the first >part of the Barry Silbert proposal independently from the second: > >"Activate Segregated Witness at an 80% threshold, signaling at bit 4" >in a way that > >The goal here is to minimize chain split risk and network disruption >while maximizing backwards compatibility and still providing for rapid >activation of segwit at the 80% threshold using bit 4. > >By activating segwit immediately and separately from any HF we can >scale quickly without risking a rushed combined segwit+HF that would >almost certainly cause widespread issues. > >Draft proposal: >https://github.com/jameshilliard/bips/blob/bip-segsignal/bip-segsignal.mediawiki > >Proposal text: ><pre> > BIP: segsignal > Layer: Consensus (soft fork) >Title: Reduced signalling threshold activation of existing segwit >deployment > Author: James Hilliard <james.hillia...@gmail.com> > Status: Draft > Type: Standards Track > Created: 2017-05-22 > License: BSD-3-Clause > CC0-1.0 ></pre> > >==Abstract== > >This document specifies a method to activate the existing BIP9 segwit >deployment with a majority hashpower less than 95%. > >==Definitions== > >"existing segwit deployment" refer to the BIP9 "segwit" deployment >using bit 1, between November 15th 2016 and November 15th 2017 to >activate BIP141, BIP143 and BIP147. > >==Motivation== > >Segwit increases the blocksize, fixes transaction malleability, and >makes scripting easier to upgrade as well as bringing many other >[https://bitcoincore.org/en/2016/01/26/segwit-benefits/ benefits]. > >This BIP provides a way for a simple majority of miners to coordinate >activation of the existing segwit deployment with less than 95% >hashpower. For a number of reasons a complete redeployment of segwit >is difficulty to do until the existing deployment expires. This is due >to 0.13.1+ having many segwit related features active already, >including all the P2P components, the new network service flag, the >witness-tx and block messages, compact blocks v2 and preferential >peering. A redeployment of segwit will need to redefine all these >things and doing so before expiry would greatly complicate testing. > >==Specification== > >While this BIP is active, all blocks must set the nVersion header top >3 bits to 001 together with bit field (1<<1) (according to the >existing segwit deployment). Blocks that do not signal as required >will be rejected. > >==Deployment== > >This BIP will be deployed by a "version bits" with an 80%(this can be >adjusted if desired) activation threshold BIP9 with the name >"segsignal" and using bit 4. > >This BIP will have a start time of midnight June 1st, 2017 (epoch time >1496275200) and timeout on midnight November 15th 2017 (epoch time >1510704000). This BIP will cease to be active when segwit is >locked-in. > >=== Reference implementation === > ><pre> >// Check if Segregated Witness is Locked In >bool IsWitnessLockedIn(const CBlockIndex* pindexPrev, const >Consensus::Params& params) >{ > LOCK(cs_main); > return (VersionBitsState(pindexPrev, params, >Consensus::DEPLOYMENT_SEGWIT, versionbitscache) == >THRESHOLD_LOCKED_IN); >} > >// SEGSIGNAL mandatory segwit signalling. >if ( VersionBitsState(pindex->pprev, chainparams.GetConsensus(), >Consensus::DEPLOYMENT_SEGSIGNAL, versionbitscache) == THRESHOLD_ACTIVE >&& > !IsWitnessLockedIn(pindex->pprev, chainparams.GetConsensus()) && >// Segwit is not locked in > !IsWitnessEnabled(pindex->pprev, chainparams.GetConsensus()) ) // >and is not active. >{ > bool fVersionBits = (pindex->nVersion & VERSIONBITS_TOP_MASK) == >VERSIONBITS_TOP_BITS; > bool fSegbit = (pindex->nVersion & >VersionBitsMask(chainparams.GetConsensus(), >Consensus::DEPLOYMENT_SEGWIT)) != 0; > if (!(fVersionBits && fSegbit)) { > return state.DoS(0, error("ConnectBlock(): relayed block must >signal for segwit, please upgrade"), REJECT_INVALID, "bad-no-segwit"); > } >} ></pre> > >https://github.com/bitcoin/bitcoin/compare/0.14...jameshilliard:segsignal-v0.14.1 > >==Backwards Compatibility== > >This deployment is compatible with the existing "segwit" bit 1 >deployment scheduled between midnight November 15th, 2016 and midnight >November 15th, 2017. Miners will need to upgrade their nodes to >support segsignal otherwise they may build on top of an invalid block. >While this bip is active users should either upgrade to segsignal or >wait for additional confirmations when accepting payments. > >==Rationale== > >Historically we have used IsSuperMajority() to activate soft forks >such as BIP66 which has a mandatory signalling requirement for miners >once activated, this ensures that miners are aware of new rules being >enforced. This technique can be leveraged to lower the signalling >threshold of a soft fork while it is in the process of being deployed >in a backwards compatible way. > >By orphaning non-signalling blocks during the BIP9 bit 1 "segwit" >deployment, this BIP can cause the existing "segwit" deployment to >activate without needing to release a new deployment. > >==References== > >*[https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-March/013714.html >Mailing list discussion] >*[https://github.com/bitcoin/bitcoin/blob/v0.6.0/src/main.cpp#L1281-L1283 >P2SH flag day activation] >*[[bip-0009.mediawiki|BIP9 Version bits with timeout and delay]] >*[[bip-0016.mediawiki|BIP16 Pay to Script Hash]] >*[[bip-0141.mediawiki|BIP141 Segregated Witness (Consensus layer)]] >*[[bip-0143.mediawiki|BIP143 Transaction Signature Verification for >Version 0 Witness Program]] >*[[bip-0147.mediawiki|BIP147 Dealing with dummy stack element >malleability]] >*[[bip-0148.mediawiki|BIP148 Mandatory activation of segwit >deployment]] >*[[bip-0149.mediawiki|BIP149 Segregated Witness (second deployment)]] >*[https://bitcoincore.org/en/2016/01/26/segwit-benefits/ Segwit >benefits] > >==Copyright== > >This document is dual licensed as BSD 3-clause, and Creative Commons >CC0 1.0 Universal. >_______________________________________________ >bitcoin-dev mailing list >bitcoin-dev@lists.linuxfoundation.org >https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev _______________________________________________ bitcoin-dev mailing list bitcoin-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
