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Test Networks

This document describes the Bitcoin Cash test networks supported by the BCHN software.

There are currently three test networks that you can access with BCHN: - testnet3 (historical testnet) - testnet4 - scalenet

These test network are maintained and supported by the wider community of protocol developers. They can be accessed by running the software (daemon, GUI and CLI) with -testnet, -testnet4 and -scalenet arguments, respectively.

Other software clients may have additional test network definitions compiled into them but these are not currently supported by BCHN and could not be accessed without further modifications to the software. If you wish BCHN to access a test network not listed above, please raise a support request.

Below, we give a brief description and an overview table for these networks.

Testnet3

This is the historical testnet in Bitcoin Cash, maintained as a fork from BTC's testnet3 since 2017. It has grown substantially in size (2020/Oct/15: 44GB), in part due to scaling tests that deposited a number of 32MB blocks, and due to the resulting time to sync a test node from scratch, has become inconvenient for quick tests.

Testnet4

Testnet4 is a testnet3 replacement (starting from a fresh genesis block) intended to be kept light-weight and quick to sync, in other words free of big block 'spam'.

Testnet4 has a reduced default blocksize to discourage high throughput and difficulty algorithm settings adjusted to make sure it recovers to be CPU-mineable quickly after someone has used an ASIC on it.

Scaling tests should use 'scalenet' instead (see next section).

Scalenet

Scalenet is intended as a place to test application performance in high-throughput situations (bigger blocks, more transactions etc).

Scalenet will have a default blocksize limit a few times higher than mainnet's limit, to serve as a proving ground for future scaling.

ASIC mining on scalenet will be encouraged and the mining difficulty will adjust slower to allow accurate exploration of mining strategies.

Every 6 months or so, scalenet's block 10,000 will be invalidated and a new block will be checkpointed in its place, clearing out the previous high volume history and keeping scalenet semi-affordable to synchronize.

Scalenet is intended to target the performance level of a ~$40/month VPS or a $500 desktop computer for the near future. Any tests that target higher performance levels are encouraged to do so by forking off of scalenet or creating their own private testnets or regtest networks.

Overview Table for BCHN-supported Test Networks

Attribute/Network testnet3 testnet4 scalenet
Default p2p port 18333 28333 38333
Network magic bytes 0xf4e5f3f4 0xe2b7daaf 0xc3afe1a2
CashAddr prefix bchtest bchtest bchtest
Default excessive block size 32MB 2MB 256MB
Block Target spacing 10 min 10 min 10 min
POW limit 2^224 2^224 2^224
ASERT half-life 1 hour 1 hour 2 days
Allow min diff blocks yes yes yes
Require standard txs no no no
Default consist. chks. no no no
Halving interval (blks) 210000 210000 210000
BIP16 height 514 1 1
BIP34 height 21111 2 2
BIP65 height 581885 3 3
BIP66 height 330776 4 4
CSV height 770112 5 5
UAHF (BCH fork) height 1155875 6 6
Nov 13 2017 HF height 1188697 3000 3000
Nov 15 2018 HF height 1267996 4000 4000
Nov 15 2019 HF height 1341711 5000 5000
May 15 2020 HF height 1378460 0 (Note 1) 0 (Note 1)
Base58 prefix: pubkey 1, 111 1, 111 1, 111
Base58 prefix: script 1, 196 1, 196 1, 196
Base58 prefix: seckey 1, 239 1, 239 1, 239
Base58 p: ext. pubkey 0x043587cf 0x043587cf 0x043587cf
Base58 p: ext. seckey 0x04358394 0x04358394 0x04358394

Note 1: set to 0 because historical sigop code has been removed from BCHN See chainparams.cpp for more detailed comments.

Further references

  1. https://bitcoincashresearch.org/t/testnet4-and-scalenet/148