CLoTH

CLoTH is a payment-channel network (PCN) simulator. Currently, it simulates the Lightning Network, the mainstream payment-channel network, which is built on top of the Bitcoin blockchain.

The key feature and novelty of CLoTH is that it exactly reproduces the code of the Lightning Network (specifically, the functions implementing routing and HTLC mechanics). This ensures the validity of the simulation results produced by CLoTH.

CLoTH simulates the execution of payments in a payment channel network. The input parameters of the simulation are read from cloth_input.txt file (see below for more details). CLoTH outputs payment-related statistics (such as probability of payment success, average payment time) in cloth_output.json.

CLoTH is currently based on lnd-v0.10.0-beta, the Golang implementation of the Lightning Network.

Install requirements

Install the requirements:

sudo apt-get install gcc
sudo apt-get install libgsl-dev
sudo apt-get install python
sudo apt-get install python-pip
pip install numpy
pip install scipy

Build

Build CLoTH:

make build

Run

Run CLoTH:

./run-simulation.sh <seed> <output-directory>

where seed is the seed used for random variables of the simulator and output-directory is the path of the directory where to store the output files generated by CLoTH (it must exist).

Input Parameters

The simulation input parameters are read from cloth_input.txt and are the following:

• generate_network_from_file. Possible values: true or false. It indicates whether the network of the simulation is generated randomly (generate_network_from_file=false) or it is taken from csv files (generate_network_from_file=true).
• nodes_filename, channels_filename, edges_filename. In case generate_network_from_file=true, the names of the csv files where nodes, channels and edges of the network are taken from. See the templates of these files in nodes_template.csv, channels_template.csv, edges_template.csv.
• n_additional_nodes. In case of randomly generated network, the number of nodes in addition to the ones of the network model. The network model is a snapshot of the Lightning Network (see files nodes_ln.csv and channels_ln.csv): the random network is generated from this snapshot using the scale-free network model.
• n_channels_per_node. In case of randomly generated network, the number of channels per additional node.
• capacity_per_channel. In case of randomly generated network, the average capacity of payment channels in satoshis.
• faulty_node_probability. The probability (between 0 and 1) that a node is faulty when forwarding a payment.
• generate_payments_from_file. Possible values: true or false. It indicates whether the payments of the simulation are generated randomly (generate_payments_from_file=false) or they are taken from a csv file (generate_network_from_file=true).
• payments_filename. In case generate_payments_from_file=true, the names of the csv files where the payments of the simulation are taken from. See the templates of this file in payments_template.csv.
• payment_rate. In case of randomly generated payments, the number of payments per second.
• n_payments. In case of randomly generated payments, the total number of payments to be simulated.
• average_payment_amount. In case of randomly generated payments, the average payment amount in satoshis.
• mpp. Possible values: 0 or 1. It indicates whether the multi-path-payment feature is activated or not.

References

I published a paper that describes the code and the functioning of CLoTH:

"CLoTH: A Lightning Network Simulator", Conoscenti Marco, Vetrò Antonio, De Martin Juan Carlos, in SoftwareX, 2021. Available here.

The description of an old version of CLoTH and previous simulation results are in my doctoral thesis:

CONOSCENTI, Marco. Capabilities and Limitations of Payment Channel Networks for Blockchain Scalability. 2019. PhD Thesis. Politecnico di Torino. Available here.