mirror of https://github.com/zcash/zips.git
188 lines
6.5 KiB
ReStructuredText
188 lines
6.5 KiB
ReStructuredText
::
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ZIP: 252
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Title: Deployment of the NU5 Network Upgrade
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Owners: teor <teor@zfnd.org>
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Daira Hopwood <daira@electriccoin.co>
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Status: Proposed
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Category: Consensus / Network
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Created: 2021-02-23
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License: MIT
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Discussions-To: <https://github.com/zcash/zips/issues/440>
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Pull-Request: <https://github.com/zcash/zips/pull/446>
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Terminology
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===========
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The key words "MUST" and "SHOULD" in this document are to be interpreted as
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described in RFC 2119. [#RFC2119]_
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The term "network upgrade" in this document is to be interpreted as described in
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ZIP 200. [#zip-0200]_
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The terms "Testnet" and "Mainnet" are to be interpreted as described in
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section 3.11 of the Zcash Protocol Specification [#protocol-networks]_.
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Abstract
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========
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This proposal defines the deployment of the NU5 network upgrade.
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Specification
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=============
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NU5 deployment
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-----------------
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The primary sources of information about NU5 consensus protocol changes are:
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- The Zcash Protocol Specification [#protocol]_
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- ZIP 200: Network Upgrade Mechanism [#zip-0200]_
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- ZIP 216: Require Canonical Point Encodings [#zip-0216]_ *proposed*
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- ZIP 224: Orchard Shielded Protocol [#zip-0224]_ *proposed*
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- ZIP 225: Version 5 Transaction Format [#zip-0225]_ *proposed*
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- ZIP 244: Transaction Identifier Non-Malleability [#zip-0244]_ *proposed*
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- The Orchard Book [#orchard-book]_
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The network handshake and peer management mechanisms defined in ZIP 201 [#zip-0201]_
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also apply to this upgrade.
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The following network upgrade constants [#zip-0200]_ are defined for the NU5
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upgrade:
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CONSENSUS_BRANCH_ID
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``0xF919A198``
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ACTIVATION_HEIGHT (NU5)
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Testnet: TODO
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Mainnet: TODO
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MIN_NETWORK_PROTOCOL_VERSION (NU5)
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Testnet: 170014
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Mainnet: 170015
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For each network (testnet and mainnet), nodes compatible with NU5 activation
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on that network MUST advertise a network protocol version that is greater than
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or equal to that network's MIN_NETWORK_PROTOCOL_VERSION (NU5).
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For each network, pre-NU5 nodes are defined as nodes advertising a protocol
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version less than that network's MIN_NETWORK_PROTOCOL_VERSION (NU5).
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Once NU5 activates on testnet or mainnet, NU5 nodes SHOULD take steps to:
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- reject new connections from pre-NU5 nodes on that network;
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- disconnect any existing connections to pre-NU5 nodes on that network.
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Backward compatibility
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======================
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Prior to the network upgrade activating on each network, NU5 and pre-NU5
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nodes are compatible and can connect to each other.
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Once the network upgrades, even though pre-NU5 nodes can still accept the
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numerically larger protocol version used by NU5 as being valid, NU5 nodes
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will always disconnect peers using lower protocol versions.
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Unlike Blossom, Heartwood, and Canopy, and like Overwinter and Sapling, NU5
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defines a new transaction version. Therefore, NU5 transactions MAY be in
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the new v5 format specified by [#zip-0225]_. Unlike previous transaction
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version updates, the existing v4 transaction format remains valid after
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NU5 activation. Both transaction formats MUST be accepted by NU5 nodes.
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Support in zcashd
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=================
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**TODO: Update as needed**
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Support for NU5 on testnet will be implemented in ``zcashd`` version 4.4.0, which
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will advertise protocol version 170014. Support for NU5 on mainnet will be implemented
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in ``zcashd`` version 5.0.0, which will advertise protocol version 170015.
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Backward compatibility in zcashd
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--------------------------------
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The minimum peer protocol version that NU5-compatible ``zcashd`` nodes will connect to
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is 170002.
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NU5 deployment for zcashd
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-------------------------
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For each network, approximately 1.5 days (defined in terms of
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block height) before the corresponding NU5 activation height, nodes compatible
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with NU5 activation on that network will change the behaviour of their peer
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connection logic in order to prefer pre-NU5 peers on that network for eviction
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from the set of peer connections::
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/**
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* The period before a network upgrade activates, where connections to upgrading peers are preferred (in blocks).
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* This was three days for upgrades up to and including Blossom, and is 1.5 days from Heartwood onward.
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*/
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static const int NETWORK_UPGRADE_PEER_PREFERENCE_BLOCK_PERIOD = 1728;
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The implementation is similar to that for Overwinter which was described in
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[#zip-0201]_.
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However, NU5 nodes will have a preference for connecting to other NU5 nodes, so
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pre-NU5 nodes will gradually be disconnected in the run up to activation.
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Support in Zebra
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================
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**TODO: Update as needed**
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Support for NU5 on testnet will be implemented in Zebra version 1.0.0, which
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will advertise protocol version 170014. Support for NU5 on mainnet will be implemented
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in Zebra version 2.0.0, which will advertise protocol version 170015.
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Backward compatibility in Zebra
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-------------------------------
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The minimum peer protocol version that NU5-compatible Zebra nodes will connect to
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is 170002. However, Zebra will immediately disconnect from nodes with a protocol
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version less than:
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- 170012 on testnet, or
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- 170013 on mainnet.
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NU5 deployment for Zebra
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------------------------
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For each network, at the corresponding NU5 activation height, nodes compatible
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with NU5 activation on that network will close any new connections with pre-NU5
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peers.
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Since Zebra maintains a reasonably strict internal request-response protocol,
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pre-NU5 nodes will gradually be disconnected after activation. (Nodes are
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temporarily disconnected if they send gossip or chain sync hints outside the
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strict request-response sequence that Zebra expects.)
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References
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==========
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.. [#RFC2119] `RFC 2119: Key words for use in RFCs to Indicate Requirement Levels <https://www.rfc-editor.org/rfc/rfc2119.html>`_
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.. [#protocol] `Zcash Protocol Specification, Version 2021.1.17 or later <protocol/nu5.pdf>`_
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.. [#protocol-networks] `Zcash Protocol Specification, Version 2021.1.17. Section 3.11: Mainnet and Testnet <protocol/nu5.pdf#networks>`_
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.. [#protocol-txnencodingandconsensus] `Zcash Protocol Specification, Version 2021.1.17. Section 7.1: Transaction Encoding and Consensus <protocol/nu5.pdf#txnencodingandconsensus>`_
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.. [#zip-0200] `ZIP 200: Network Upgrade Activation Mechanism <zip-0200.rst>`_
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.. [#zip-0201] `ZIP 201: Network Peer Management for Overwinter <zip-0201.rst>`_
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.. [#zip-0216] `ZIP 216: Require Canonical Point Encodings <zip-0216.rst>`_
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.. [#zip-0224] `ZIP 224: Orchard Shielded Protocol <zip-0224.rst>`_
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.. [#zip-0225] `ZIP 225: Version 5 Transaction Format <zip-0225.rst>`_
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.. [#zip-0244] `ZIP 244: Transaction Identifier Non-Malleability <zip-0244.rst>`_
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.. [#orchard-book] `The Orchard Book <https://zcash.github.io/orchard/>`_
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