Connect Public Nodes

Overview

This document provides a user manual for connecting to the public Testnet nodes of the Fiber network. It covers running a local node, establishing a channel with a public node, and transferring CKB and RUSD(stablecoin) within the channels. If you haven't read the Run a Fiber Node guide and the Basic Transfer Example, it is highly recommended to read them first.

Testnet Public Nodes’ Addresses

Node1

"/ip4/18.162.235.225/tcp/8119/p2p/QmXen3eUHhywmutEzydCsW4hXBoeVmdET2FJvMX69XJ1Eo"

Node2

"/ip4/18.163.221.211/tcp/8119/p2p/QmbKyzq9qUmymW2Gi8Zq7kKVpPiNA1XUJ6uMvsUC4F3p89"

Local Node Deployment

Download FNN

Example for macOS (Apple silicon):

mkdir tmp && cd tmp
wget https://github.com/nervosnetwork/fiber/releases/download/v0.4.0/fnn_v0.4.0-x86_64-darwin-portable.tar.gz
tar xzvf fnn_v0.4.0-x86_64-darwin-portable.tar.gz

Export the account private key to the Fiber node’s CKB directory

Use ckb-cli to create an account, which will later be used to pay for opening channels between your local node and the public Testnet node. If ckb-cli is not installed, please download it from the releases page.

# Create a local node directory named nodeA
mkdir -p testnet-fnn/nodeA/ckb
./ckb-cli account new
./ckb-cli account export  --lock-arg 0xcc015401df73a3287d8b2b19f0cc23572ac8b14d --extended-privkey-path exported-key
head -n 1 ./exported-key > testnet-fnn/nodeA/ckb/key
chmod 600 testnet-fnn/nodeA/ckb/key
# check nodeA key
./ckb-cli util key-info  --privkey-path testnet-fnn/nodeA/ckb/key

Copy config.yml

cp config/testnet/config.yml testnet-fnn/nodeA

Fund nodeA’s address with 10000 CKB and 20 RUSD via Faucet

The RUSD faucet cannot directly fill an address, so you can first claim 20 RUSD through a wallet like JoyID, then transfer it to nodeA’s address from the JoyID wallet page.
- CKB Faucet: https://faucet.nervos.org
- RUSD Faucet: https://testnet0815.stablepp.xyz/faucet

Start the nodeA

RUST_LOG=info ./fnn -c testnet-fnn/nodeA/config.yml -d testnet-fnn/nodeA > testnet-fnn/nodeA/a.log 2>&1 &

Establishing a CKB Channel with Public Node1

Establish a network connection between nodeA and node1

curl -s --location 'http://127.0.0.1:8227' --header 'Content-Type: application/json' --data '{
    "id": 1,
    "jsonrpc": "2.0",
    "method": "connect_peer",
    "params": [
        {
            "address": "/ip4/18.162.235.225/tcp/8119/p2p/QmXen3eUHhywmutEzydCsW4hXBoeVmdET2FJvMX69XJ1Eo"
        }
    ]
}'

{ "jsonrpc": "2.0", "result": null, "id": 1 }

Establish a channel with 500 CKB: nodeA (500 CKB) ⟺ node1 (250 CKB)

node1 has open_channel_auto_accept_min_ckb_funding_amount set at 438 CKB, so please input 500 CKB or more.

curl -s --location 'http://127.0.0.1:8227' --header 'Content-Type: application/json' --data '{
    "id": 2,
    "jsonrpc": "2.0",
    "method": "open_channel",
    "params": [
        {
            "peer_id": "QmXen3eUHhywmutEzydCsW4hXBoeVmdET2FJvMX69XJ1Eo",
            "funding_amount": "0xba43b7400",
            "public": true
        }
    ]
}'

{
  "jsonrpc": "2.0",
  "result": {
    "temporary_channel_id": "0x30089ec4c8ce1e1d4930220c2bff856eec7ab44550e15b76d62489fd42eaafe8"
  },
  "id": 2
}

Query the channels between nodeA and node1

curl -s --location 'http://127.0.0.1:8227' --header 'Content-Type: application/json' --data '{
    "id": 3,
    "jsonrpc": "2.0",
    "method": "list_channels",
    "params": [
        {
            "peer_id": "QmXen3eUHhywmutEzydCsW4hXBoeVmdET2FJvMX69XJ1Eo"
        }
    ]
}'

Wait until the state_name changes to CHANNEL_READY.

Note: When the channel has just changed to the CHANNEL_READY state and you attempt to use send_payment, you may still encounter an error: Failed to build route. It is advisable to wait for some time before trying again.

{"jsonrpc":"2.0","result":{"channels":[{"channel_id":"0x26ce85d57fb4a1a826cbf4862358862317a83b775090625550d8be12c6ce9569","is_public":true,"channel_outpoint":"0x9bb2a8a4bebaf793a235ba2ec87051ae0018b58736b6741df74009ca8101cb8d00000000","peer_id":"QmXen3eUHhywmutEzydCsW4hXBoeVmdET2FJvMX69XJ1Eo","funding_udt_type_script":null,"state":{"state_name":"CHANNEL_READY","state_flags":[]},"local_balance":"0xa32aef600","offered_tlc_balance":"0x0","remote_balance":"0x460913c00","received_tlc_balance":"0x0","latest_commitment_transaction_hash":"0x18ef541a5a195c0ea4715a7783964b3c4be8fba6bd25542e626f91ef1673e3e4","created_at":"0x195892d237f","enabled":true,"tlc_expiry_delta":"0x5265c00","tlc_fee_proportional_millionths":"0x3e8"}]},"id":3

Why is the local_balance 0xa32aef600 (43,800,000,000) and the remote_balance 0x460913c00 (18,800,000,000)?

This channel was established with nodeA contributing 500 CKB and node1 contributing 250 CKB.

Since each Cell requires a minimum of 62 CKB, this amount is reserved to ensure that there are sufficient funds to cover Cell occupancy costs during on-chain settlement (when the channel closes). These 62 CKB will be returned to their respective nodes at the time of on-chain settlement.

Actual available funds in the channel:

nodeA: 500 CKB - 62 CKB = 438 CKB (local_balance is 0xa32aef600)

node1: 250 CKB - 62 CKB = 188 CKB (remote_balance is 0x460913c00)

Call the new_invoice API on node2 to generate an invoice

Set the amount to 0x5f5e100 (100,000,000 shannon), which is equivalent to 1 CKB. The payment_preimage should be a unique 32-byte hexadecimal number.

# Generate a 32-byte random number and represent it in hexadecimal
payment_preimage="0x$(openssl rand -hex 32)"
echo $payment_preimage

0xbc03e507befb33cfd5953a2e7046428e69cb8f0ade65c05d3661128aa4b4fff9

curl -s --location 'http://18.163.221.211:8227' --header 'Content-Type: application/json' --data '{
    "id": 4,
    "jsonrpc": "2.0",
    "method": "new_invoice",
    "params": [
        {
            "amount": "0x5f5e100",
            "currency": "Fibt",
            "description": "test invoice generated by node2",
            "expiry": "0xe10",
            "final_cltv": "0x28",
            "payment_preimage": "0xbc03e507befb33cfd5953a2e7046428e69cb8f0ade65c05d3661128aa4b4fff9",
            "hash_algorithm": "sha256"
        }
    ]
}'

{
  "jsonrpc": "2.0",
  "result": {
    "invoice_address": "fibt1000000001peseucdphcxgfw0pnm6vk3uftyc36dakyjchs0p0unk9gaug0h36uhafww9pvy38gcesad084rx48xgx9xts49yp9fn87yfchld3l3qu5n0pfzvvy8c9g7dksrcxyrtk3hymspezmvtx4vg5v6uvt6tyxmq5uhrfejpk0j6wue9ef2pa8mzmrgqaz3wucutujtjcmq2x8f36faxuctg62ny73mhaj7rpwqe0ns0wp5wr4tku7qcl9r4a3swluvd2jqqwmsl7wsz4cwvhhe7p8tr7hz5qkqwr3r38hukckqzjtmntd8zrz0ywux4u8df005hl76thzsp9hz7dyefzk4mqhx4x9el98zjzmhcveqpfeur79",
    "invoice": {
      "currency": "Fibt",
      "amount": "0x5f5e100",
      "signature": "0e1b101f1e0e100215180e0c1717191e01070b031e1702140016000e0311031107171c1618160002120b1b130b0d070203020f040e1c06151c070d090f0f14171f1e1a0b170210010517021e0d0419090216151b001706150605191f05070212021b17180c190001",
      "data": {
        "timestamp": "0x1958944fa64",
        "payment_hash": "0xafb604f74c28009732ed4c82983cf1efaddf62ee36442f360fb4a8c79b845432",
        "attrs": [
          { "Description": "test invoice generated by node2" },
          { "ExpiryTime": { "secs": 3600, "nanos": 0 } },
          { "HashAlgorithm": "sha256" },
          {
            "PayeePublicKey": "0291a6576bd5a94bd74b27080a48340875338fff9f6d6361fe6b8db8d0d1912fcc"
          }
        ]
      }
    }
  },
  "id": 4
}

Record the invoice_address from the response.

Before nodeA sends the payment, first query the local_balance and remote_balance of each channel

nodeA ⟺ node1

As shown in Step 3, the response included: {"local_balance":"0xa32aef600","remote_balance":"0x460913c00"}

node1 ⟺ node2

curl -s --location 'http://18.162.235.225:8227' --header 'Content-Type: application/json' --data '{
    "id": 5,
    "jsonrpc": "2.0",
    "method": "list_channels",
    "params": [
        {
            "peer_id": "QmbKyzq9qUmymW2Gi8Zq7kKVpPiNA1XUJ6uMvsUC4F3p89"
        }
    ]
}'

{
  "jsonrpc": "2.0",
  "result": {
    "channels": [
      {
        "channel_id": "0x29a2e93e70fcfcd8b64fd74646b3893247f2a73a9dd8706298b5defa17bfee0a",
        "is_public": true,
        "channel_outpoint": "0xa065311059be4d2194d9d6dbc428fe794ed3c6d91e08fe1d960d1574c19f88d400000000",
        "peer_id": "QmbKyzq9qUmymW2Gi8Zq7kKVpPiNA1XUJ6uMvsUC4F3p89",
        "funding_udt_type_script": {
          "code_hash": "0x1142755a044bf2ee358cba9f2da187ce928c91cd4dc8692ded0337efa677d21a",
          "hash_type": "type",
          "args": "0x878fcc6f1f08d48e87bb1c3b3d5083f23f8a39c5d5c764f253b55b998526439b"
        },
        "state": { "state_name": "CHANNEL_READY", "state_flags": [] },
        "local_balance": "0x173c0e06bb",
        "offered_tlc_balance": "0x1f5",
        "remote_balance": "0xc68e145",
        "received_tlc_balance": "0x0",
        "latest_commitment_transaction_hash": "0x195e1cbd1dd062752e776a44dd9c12f3b83a69dfdd1e22edff19025572bcbd25",
        "created_at": "0x1944491c154",
        "enabled": true,
        "tlc_expiry_delta": "0x5265c00",
        "tlc_fee_proportional_millionths": "0x3e8"
      },
      {
        "channel_id": "0x4cd5bdcac419b203fd5752c4daa00a6f24305123d65f7a7fa6b455df82e97eee",
        "is_public": true,
        "channel_outpoint": "0xe7d8464be26933021810f31252a98e9b2b1ff00f70173fafb134861ce21bccbb00000000",
        "peer_id": "QmbKyzq9qUmymW2Gi8Zq7kKVpPiNA1XUJ6uMvsUC4F3p89",
        "funding_udt_type_script": {
          "code_hash": "0x1142755a044bf2ee358cba9f2da187ce928c91cd4dc8692ded0337efa677d21a",
          "hash_type": "type",
          "args": "0x878fcc6f1f08d48e87bb1c3b3d5083f23f8a39c5d5c764f253b55b998526439b"
        },
        "state": { "state_name": "CHANNEL_READY", "state_flags": [] },
        "local_balance": "0x1748630df7",
        "offered_tlc_balance": "0x0",
        "remote_balance": "0x13da09",
        "received_tlc_balance": "0x0",
        "latest_commitment_transaction_hash": "0x6bd9890fd65297359079d87a995d794becc90bafd5eca9676ccbfd96abcb3ffd",
        "created_at": "0x194448fc295",
        "enabled": true,
        "tlc_expiry_delta": "0x5265c00",
        "tlc_fee_proportional_millionths": "0x3e8"
      },
      {
        "channel_id": "0x9e72e8dbf7409a5aaf456dbe25f61247450f72079249ee508bb23cb14d0408b1",
        "is_public": true,
        "channel_outpoint": "0x49f5f1cf664d48df66943989ef87d1316f1dffe5aec96db9ee8f1b6879ccac1b00000000",
        "peer_id": "QmbKyzq9qUmymW2Gi8Zq7kKVpPiNA1XUJ6uMvsUC4F3p89",
        "funding_udt_type_script": {
          "code_hash": "0x1142755a044bf2ee358cba9f2da187ce928c91cd4dc8692ded0337efa677d21a",
          "hash_type": "type",
          "args": "0x878fcc6f1f08d48e87bb1c3b3d5083f23f8a39c5d5c764f253b55b998526439b"
        },
        "state": { "state_name": "CHANNEL_READY", "state_flags": [] },
        "local_balance": "0xa38b9d",
        "offered_tlc_balance": "0x0",
        "remote_balance": "0x1747d35c63",
        "received_tlc_balance": "0x0",
        "latest_commitment_transaction_hash": "0x6ad24a7dda73ed2ff896401ba4487c207362510670295b60288040df4b78884d",
        "created_at": "0x194448ea599",
        "enabled": true,
        "tlc_expiry_delta": "0x5265c00",
        "tlc_fee_proportional_millionths": "0x3e8"
      },
      {
        "channel_id": "0x632548057f0f13752e6d55ea666a93aaae450f2cf6e31093142c940071648f88",
        "is_public": true,
        "channel_outpoint": "0xb0fcf51f0587c3c623377d054874dbb6ff1e8a26950834ace30dc88003af05f900000000",
        "peer_id": "QmbKyzq9qUmymW2Gi8Zq7kKVpPiNA1XUJ6uMvsUC4F3p89",
        "funding_udt_type_script": {
          "code_hash": "0x1142755a044bf2ee358cba9f2da187ce928c91cd4dc8692ded0337efa677d21a",
          "hash_type": "type",
          "args": "0x878fcc6f1f08d48e87bb1c3b3d5083f23f8a39c5d5c764f253b55b998526439b"
        },
        "state": { "state_name": "CHANNEL_READY", "state_flags": [] },
        "local_balance": "0xc505f",
        "offered_tlc_balance": "0x0",
        "remote_balance": "0x17486a97a1",
        "received_tlc_balance": "0x0",
        "latest_commitment_transaction_hash": "0x62892d0751149af74d6baa7d7e09215427858d8dd047ae62b9179c8779d236e5",
        "created_at": "0x194448dbf4b",
        "enabled": true,
        "tlc_expiry_delta": "0x5265c00",
        "tlc_fee_proportional_millionths": "0x3e8"
      },
      {
        "channel_id": "0x0d54942293e7bb2704749e85741fd65e9a3d2f4eb380eb33b0aa0d38f891638f",
        "is_public": true,
        "channel_outpoint": "0xf846f128450f3319352e8b48a38060feaed09d834f8d1c4d98477069f64ef78100000000",
        "peer_id": "QmbKyzq9qUmymW2Gi8Zq7kKVpPiNA1XUJ6uMvsUC4F3p89",
        "funding_udt_type_script": null,
        "state": { "state_name": "CHANNEL_READY", "state_flags": [] },
        "local_balance": "0x45a9b5cf3",
        "offered_tlc_balance": "0x0",
        "remote_balance": "0x916e2dc010d",
        "received_tlc_balance": "0x0",
        "latest_commitment_transaction_hash": "0x68002aad33179b3d7bd21234ecf7a296f71833ecd4a69632e294c583e73181ff",
        "created_at": "0x1944489267e",
        "enabled": true,
        "tlc_expiry_delta": "0x5265c00",
        "tlc_fee_proportional_millionths": "0x3e8"
      },
      {
        "channel_id": "0x4c84c39f5166eb15631fca02dbc1910fa0139ad0ec6732ab2cc51c275d8fc11b",
        "is_public": true,
        "channel_outpoint": "0x5c871464dc91eaf6fb262157329dc90d00b96cafaf272bd322184cab5d2601fa00000000",
        "peer_id": "QmbKyzq9qUmymW2Gi8Zq7kKVpPiNA1XUJ6uMvsUC4F3p89",
        "funding_udt_type_script": null,
        "state": { "state_name": "CHANNEL_READY", "state_flags": [] },
        "local_balance": "0x504f21d045c",
        "offered_tlc_balance": "0x0",
        "remote_balance": "0x4164b5a59a4",
        "received_tlc_balance": "0x0",
        "latest_commitment_transaction_hash": "0x117b18ac0789b44e3a08504d503a9cbf29acd2a4050069a640f67d7ec8209a00",
        "created_at": "0x1944487f433",
        "enabled": true,
        "tlc_expiry_delta": "0x5265c00",
        "tlc_fee_proportional_millionths": "0x3e8"
      },
      {
        "channel_id": "0x728fce53aaedf010b8f7c09497f3ab8527382ada0b6691cc61c04badf4837296",
        "is_public": true,
        "channel_outpoint": "0x713364717227e24ebcf1b1ddd469f3f278e8b4069ebd23631d2aca12fffa2e1c00000000",
        "peer_id": "QmbKyzq9qUmymW2Gi8Zq7kKVpPiNA1XUJ6uMvsUC4F3p89",
        "funding_udt_type_script": null,
        "state": { "state_name": "CHANNEL_READY", "state_flags": [] },
        "local_balance": "0x916d6f044e9",
        "offered_tlc_balance": "0x0",
        "remote_balance": "0x466871917",
        "received_tlc_balance": "0x0",
        "latest_commitment_transaction_hash": "0x83a0d88fd312bb14f3cf953888257581d859230d1230b21b487a5cda48be7c8d",
        "created_at": "0x1944485b77f",
        "enabled": true,
        "tlc_expiry_delta": "0x5265c00",
        "tlc_fee_proportional_millionths": "0x3e8"
      },
      {
        "channel_id": "0xfb27dc9ebc391440afe5e25cd4dc25e302b6fbb089397eda07decdb04db14b9e",
        "is_public": true,
        "channel_outpoint": "0x56b3edb1dd683f9149286069881395bb878c69fbff638b7dc6d1bca1c83acd6400000000",
        "peer_id": "QmbKyzq9qUmymW2Gi8Zq7kKVpPiNA1XUJ6uMvsUC4F3p89",
        "funding_udt_type_script": null,
        "state": { "state_name": "CHANNEL_READY", "state_flags": [] },
        "local_balance": "0x48ab5ace976",
        "offered_tlc_balance": "0x0",
        "remote_balance": "0x49087ca748a",
        "received_tlc_balance": "0x0",
        "latest_commitment_transaction_hash": "0xe6a25f3420db9f0a436df0214fa5622a39a8975549f861f941d33cf8fba19e2e",
        "created_at": "0x1944483b877",
        "enabled": true,
        "tlc_expiry_delta": "0x5265c00",
        "tlc_fee_proportional_millionths": "0x3e8"
      },
      {
        "channel_id": "0x92b04366f93500efef5f28ba79704fa3a0e3771148899aa8836f0e5d2fbc38d5",
        "is_public": true,
        "channel_outpoint": "0x61368447e60f0aa15ef61e13539d19d2f32fbacb20728db4248d8c82fa56079a00000000",
        "peer_id": "QmbKyzq9qUmymW2Gi8Zq7kKVpPiNA1XUJ6uMvsUC4F3p89",
        "funding_udt_type_script": null,
        "state": { "state_name": "CHANNEL_READY", "state_flags": [] },
        "local_balance": "0x48ab5acd200",
        "offered_tlc_balance": "0x0",
        "remote_balance": "0x49087ca8c00",
        "received_tlc_balance": "0x0",
        "latest_commitment_transaction_hash": "0x6048cd50eb71aa8fabda1a5d567ceb5fb84181efbb36d839245e253e382bbfaf",
        "created_at": "0x194447dd85a",
        "enabled": true,
        "tlc_expiry_delta": "0x5265c00",
        "tlc_fee_proportional_millionths": "0x3e8"
      }
    ]
  },
  "id": 5
}

Find all entries in the response where funding_udt_type_script is null.

{"local_balance":"0x45a9b5cf3","remote_balance":"0x916e2dc010d"}
{"local_balance":"0x504f21d045c","remote_balance":"0x4164b5a59a4"}
{"local_balance":"0x916d6f044e9","remote_balance":"0x466871917"}
{"local_balance":"0x48ab5ace976","remote_balance":"0x49087ca748a"}
{"local_balance":"0x48ab5acd200","remote_balance":"0x49087ca8c00"}

Send a send_payment request to nodeA to pay node2

Pass in the previously recorded invoice_address to the send_payment request

curl -s --location 'http://127.0.0.1:8227' --header 'Content-Type: application/json' --data '{
    "id": 6,
    "jsonrpc": "2.0",
    "method": "send_payment",
    "params": [
        {
            "invoice": "fibt1000000001peseucdphcxgfw0pnm6vk3uftyc36dakyjchs0p0unk9gaug0h36uhafww9pvy38gcesad084rx48xgx9xts49yp9fn87yfchld3l3qu5n0pfzvvy8c9g7dksrcxyrtk3hymspezmvtx4vg5v6uvt6tyxmq5uhrfejpk0j6wue9ef2pa8mzmrgqaz3wucutujtjcmq2x8f36faxuctg62ny73mhaj7rpwqe0ns0wp5wr4tku7qcl9r4a3swluvd2jqqwmsl7wsz4cwvhhe7p8tr7hz5qkqwr3r38hukckqzjtmntd8zrz0ywux4u8df005hl76thzsp9hz7dyefzk4mqhx4x9el98zjzmhcveqpfeur79"
        }
    ]
}'

{
  "jsonrpc": "2.0",
  "result": {
    "payment_hash": "0xafb604f74c28009732ed4c82983cf1efaddf62ee36442f360fb4a8c79b845432",
    "status": "Created",
    "created_at": "0x1958957cc7d",
    "last_updated_at": "0x1958957cc7d",
    "failed_error": null,
    "fee": "0x186a0"
  },
  "id": 6
}

Repeat Steps 4 and 6 two more times

Performing two additional new_invoice and send_payment requests, keeping the amount set to 0x5f5e100.
Query the local_balance and remote_balance of each channel again

nodeA ⟺ node1

Balances changed from{"local_balance":"0xa32aef600","remote_balance":"0x460913c00"}to{"local_balance":"0xa2cb78e60","remote_balance":"0x46688a3a0"}.

node1 ⟺ node2

Balances changed from {"local_balance":"0x48ab5acd200","remote_balance":"0x49087ca8c00"}to{"local_balance":"0x48aa3cb2f00","remote_balance":"0x49099ac2f00"}.

All other entries remain unchanged.

This means the channel balances have changed as follows before and after the payments:
- Before payments
  
  nodeA (43800000000) ⟺ node1 (18800000000)
  
  node1 (4993800000000) ⟺ node2 (5018800000000)
- After payments
  
  nodeA (43499700000) ⟺ node1 (19100300000)
  
  node1 (4993500000000) ⟺ node2 (5019100000000)
Funds changes:

nodeA: 43499700000 - 43800000000 = -300300000

node1: 4993500000000 + 19100300000 - 4993800000000 - 18800000000 = 300000

node2: 5019100000000 - 5018800000000 = 300000000

Conclusion: Three CKB payments of 100,000,000 shannon each from nodeA → node1 → node2 were successfully completed. The intermediate node (node1) earned a total fee of 300,000 shannon.

Close the channel between nodeA and node1

Pass in the channel_id and the receiving address as parameters.

curl -s --location 'http://127.0.0.1:8227' --header 'Content-Type: application/json' --data '{
    "id": 9,
    "jsonrpc": "2.0",
    "method": "shutdown_channel",
    "params": [
        {
            "channel_id": "0x26ce85d57fb4a1a826cbf4862358862317a83b775090625550d8be12c6ce9569",
            "close_script": {
                "code_hash": "0x9bd7e06f3ecf4be0f2fcd2188b23f1b9fcc88e5d4b65a8637b17723bbda3cce8",
                "hash_type": "type",
                "args": "0xcc015401df73a3287d8b2b19f0cc23572ac8b14d"
            },
            "fee_rate": "0x3FC"
        }
    ]
}'

{ "jsonrpc": "2.0", "result": null, "id": 9 }

You can see on the CKB Explorer that nodeA’s address received a new transaction of +496.99699462 CKB. This indicates that multiple off-chain CKB transfers through Fiber nodes are eventually settled on-chain upon channel closure via the shutdown_channel request.

Establishing a UDT Channel with Public Node1

Establish a network connection between nodeA and node1

Establish a channel with 20 RUSD: nodeA (20 RUSD) ⟺ node1 (0)

Node1 has auto_accept_amount for RUSD set to 20 RUSD, so please input 20 RUSD or more as the funding_amount.

curl -s --location 'http://127.0.0.1:8227' --header 'Content-Type: application/json' --data '{
    "id": 2,
    "jsonrpc": "2.0",
    "method": "open_channel",
    "params": [
        {
            "peer_id": "QmXen3eUHhywmutEzydCsW4hXBoeVmdET2FJvMX69XJ1Eo",
            "funding_amount": "0x2540be400",
            "public": true,
            "funding_udt_type_script": {
                "code_hash": "0x1142755a044bf2ee358cba9f2da187ce928c91cd4dc8692ded0337efa677d21a",
                "hash_type": "type",
                "args": "0x878fcc6f1f08d48e87bb1c3b3d5083f23f8a39c5d5c764f253b55b998526439b"
            }
        }
    ]
}'

{
  "jsonrpc": "2.0",
  "result": {
    "temporary_channel_id": "0xa3137338377b67ea90c2f2c15b7d60ad27b3e891095f4b093772d7db3aa79344"
  },
  "id": 2
}

Query the channels between nodeA and node1

curl -s --location 'http://127.0.0.1:8227' --header 'Content-Type: application/json' --data '{
    "id": 3,
    "jsonrpc": "2.0",
    "method": "list_channels",
    "params": [
        {
            "peer_id": "QmXen3eUHhywmutEzydCsW4hXBoeVmdET2FJvMX69XJ1Eo"
        }
    ]
}'

{
  "jsonrpc": "2.0",
  "result": {
    "channels": [
      {
        "channel_id": "0x75dce35923a79086afd0f81b0134ac87619756b6c04a15669ce232aa7db142d8",
        "is_public": true,
        "channel_outpoint": "0x8e133056792766e1fd34e870fb33990b58c4ebb9615526b38dacdf3686cf6d3f00000000",
        "peer_id": "QmXen3eUHhywmutEzydCsW4hXBoeVmdET2FJvMX69XJ1Eo",
        "funding_udt_type_script": {
          "code_hash": "0x1142755a044bf2ee358cba9f2da187ce928c91cd4dc8692ded0337efa677d21a",
          "hash_type": "type",
          "args": "0x878fcc6f1f08d48e87bb1c3b3d5083f23f8a39c5d5c764f253b55b998526439b"
        },
        "state": { "state_name": "CHANNEL_READY", "state_flags": [] },
        "local_balance": "0x2540be400",
        "offered_tlc_balance": "0x0",
        "remote_balance": "0x0",
        "received_tlc_balance": "0x0",
        "latest_commitment_transaction_hash": "0x2b0b36c5db14778484358a4641bfe00a4f351660c280255ef8e8538898e399d0",
        "created_at": "0x1958977b7be",
        "enabled": true,
        "tlc_expiry_delta": "0x5265c00",
        "tlc_fee_proportional_millionths": "0x3e8"
      }
    ]
  },
  "id": 3
}

Call the new_invoice API on node2 to generate an invoice

Set the amount to 0x5f5e100 (100,000,000), which is equivalent to 1 RUSD.

Here, a unique payment_preimage is still required. You can generate one using: echo "0x$(openssl rand -hex 32)"

curl -s --location 'http://18.163.221.211:8227' --header 'Content-Type: application/json' --data '{
    "id": 4,
    "jsonrpc": "2.0",
    "method": "new_invoice",
    "params": [
        {
            "amount": "0x5f5e100",
            "currency": "Fibt",
            "description": "test invoice generated by node2",
            "expiry": "0xe10",
            "final_cltv": "0x28",
            "payment_preimage": "0xf7d121b132b4f53bb8301591028b34fccc065f92161bb6e7d41cf6d32ad32a22",
            "hash_algorithm": "sha256",
            "udt_type_script": {
                "code_hash": "0x1142755a044bf2ee358cba9f2da187ce928c91cd4dc8692ded0337efa677d21a",
                "hash_type": "type",
                "args": "0x878fcc6f1f08d48e87bb1c3b3d5083f23f8a39c5d5c764f253b55b998526439b"
            }
        }
    ]
}'

{
  "jsonrpc": "2.0",
  "result": {
    "invoice_address": "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",
    "invoice": {
      "currency": "Fibt",
      "amount": "0x5f5e100",
      "signature": "161b1405170f18161b1e1c090c0a0a010a190409061c1b1a1107130413040f1a0204080504121212150f1b031b171a040417030102191d010a1317090f1f1c120e1909121b0d041b17101f071e1b020d170a151a15121d0d081d12151816171c0d000215190a1801",
      "data": {
        "timestamp": "0x1958e785913",
        "payment_hash": "0x6a356ad088b704a9c53728029bd968e894daf5adab1da838bf06f6755239b005",
        "attrs": [
          { "Description": "test invoice generated by node2" },
          { "ExpiryTime": { "secs": 3600, "nanos": 0 } },
          {
            "UdtScript": "0x550000001000000030000000310000001142755a044bf2ee358cba9f2da187ce928c91cd4dc8692ded0337efa677d21a0120000000878fcc6f1f08d48e87bb1c3b3d5083f23f8a39c5d5c764f253b55b998526439b"
          },
          { "HashAlgorithm": "sha256" },
          {
            "PayeePublicKey": "0291a6576bd5a94bd74b27080a48340875338fff9f6d6361fe6b8db8d0d1912fcc"
          }
        ]
      }
    }
  },
  "id": 4
}

Before nodeA sends the payment, first query the local_balance and remote_balance of each channel

nodeA ⟺ node1

As shown in Step 3, the response included: {"local_balance":"0x77359400","remote_balance":"0x0"}

node1 ⟺ node2

curl -s --location 'http://18.162.235.225:8227' --header 'Content-Type: application/json' --data '{
    "id": 5,
    "jsonrpc": "2.0",
    "method": "list_channels",
    "params": [
        {
            "peer_id": "QmbKyzq9qUmymW2Gi8Zq7kKVpPiNA1XUJ6uMvsUC4F3p89"
        }
    ]
}'

Find all entries in the response where funding_udt_type_script is not null.

{"local_balance":"0x172a2c63bb","remote_balance":"0x1e4a8445"}
{"local_balance":"0x1748630df7","remote_balance":"0x13da09"}
{"local_balance":"0xa38b9d","remote_balance":"0x1747d35c63"}
{"local_balance":"0xc505f","remote_balance":"0x17486a97a1"}

Send a send_payment request to nodeA to pay node2

curl -s --location 'http://127.0.0.1:8227' --header 'Content-Type: application/json' --data '{
    "id": 6,
    "jsonrpc": "2.0",
    "method": "send_payment",
    "params": [
        {
            "invoice": "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"
        }
    ]
}'

{
  "jsonrpc": "2.0",
  "result": {
    "payment_hash": "0x6a356ad088b704a9c53728029bd968e894daf5adab1da838bf06f6755239b005",
    "status": "Created",
    "created_at": "0x1958e7b66b5",
    "last_updated_at": "0x1958e7b66b5",
    "failed_error": null,
    "fee": "0x186a0"
  },
  "id": 6
}

Repeat Steps 4 and 6 two more times

Performing two additional new_invoice and send_payment requests, keeping the amount set to 0x5f5e100.
Query the local_balance and remote_balance of each channel again

nodeA ⟺ node1

Balances changed from{"local_balance":"0x77359400","remote_balance":"0x0"}to{"local_balance":"0x654f5d20","remote_balance":"0x11e636e0"}

node1 ⟺ node2

Balances changed from{"local_balance":"0x172a2c63bb","remote_balance":"0x1e4a8445"}to{"local_balance":"0x17184ac0bb","remote_balance":"0x302c2745"}

All other entries remain unchanged.

This means the channel balances have changed as follows before and after the payments:
- Before payments
  
  nodeA (2000000000) ⟺ node1 (0)
  
  node1 (99491799995) ⟺ node2 (508200005)
- After payments
  
  nodeA (1699700000) ⟺ node1 (300300000)
  
  node1 (99191799995) ⟺ node2 (808200005)
Funds changes:

nodeA: 1699700000 - 2000000000 = -300300000

node1: 99191799995 + 300300000 - 99491799995 = 300000

node2: 808200005 - 508200005 = 300000000

Conclusion: Three UDT payments of 100,000,000 each from nodeA → node1 → node2 were successfully completed. The intermediate node (node1) earned a total fee of 300,000.

Close the channel between nodeA and node1

curl -s --location 'http://127.0.0.1:8227' --header 'Content-Type: application/json' --data '{
    "id": 9,
    "jsonrpc": "2.0",
    "method": "shutdown_channel",
    "params": [
        {
            "channel_id": "0x75dce35923a79086afd0f81b0134ac87619756b6c04a15669ce232aa7db142d8",
            "close_script": {
                "code_hash": "0x9bd7e06f3ecf4be0f2fcd2188b23f1b9fcc88e5d4b65a8637b17723bbda3cce8",
                "hash_type": "type",
                "args": "0xcc015401df73a3287d8b2b19f0cc23572ac8b14d"
            },
            "fee_rate": "0x3FC"
        }
    ]
}'

{ "jsonrpc": "2.0", "result": null, "id": 9 }

You can see on the CKB Explorer that nodeA’s address received a new transaction of +16.997 RUSD. This indicates that multiple off-chain UDT transfers through Fiber nodes are eventually settled on-chain upon channel closure via the shutdown_channel request.

Connect Public Nodes

Overview

Testnet Public Nodes’ Addresses

Node1

Node2

Local Node Deployment

Establishing a CKB Channel with Public Node1

Establishing a UDT Channel with Public Node1

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