As a on-chain project based on real business, NetFlowCoin introduces a pledge mechanism to protect the sustainable development of the network and the interests of users, and regulate node behavior to prevent slash. Why do we need a pledge mechanism?
1.1 Traditional incentive methods cannot meet the needs of NetFlowCoin
Traditional blockchains such as Bitcoin or Ethereum are therefore mainly serving the main chain, and the ledger is kept at the full node, so as long as there are nodes, the data on the chain will not be lost.
NetFlowCoin is linked to the real business of SDN/SDVN, it is not only necessary to keep the ledger on the chain, but to maintain the security of the entire network. Offline nodes will cause losses to users.
1.2 The need for consensus of on-chain
The PoW-based consensus is not sensitive to users joining or leaving, and the consensus protocol will automatically adjust it. NetFlowCoin’s innovative PoS and original PoF consensus have completed real-world asset digitization through a powerful distributed network. If there is a loss of computing power, it will have a greater impact on the stability of the entire network.
1.3 The need for service continuity
The ultimate goal of NetFlowCoin is to build a distributed value network based on SDN/SDVN technology. This network operates independently of the Internet. Services on the network need to be guaranteed for stable operation in order to achieve the sustainability of the digital assets (value) carried on it. Sustainability cannot rely solely on incentives, but also on guarantee mechanisms.
Therefore, for the above reasons, pledge is an important component of NetFlowCoin & SDN/SDVN, and it is also a reliable guarantee for the actual implementation of the NetFlowCoin project.
NetFlowCoin pledge refers to a node’s commitment, and all nodes participating in production must invest resources in order to complete the promise of flow services and network support, and to provide sufficient guarantee for consensus.
Pledge is divided into block generation pledge and traffic pledge.
Block generation pledge is similar to Ethereum 2.0. It is expected that nodes participating in block generation need to pledge a certain number (36) of NFC in order to have the right to run for witness nodes.
All roles participating in traffic generation need to complete the pledge, and only the nodes after the pledge can get rewards by flow service and bandwidth support. Compared with block generation pledge, traffic pledge are much more complicated, since traffic pledge involves real businesses and cases.
The design of traffic pledge mainly considers the following aspects:
4.1 The amount of pledge cannot be too large or too small
In order to prevent traffic production from being monopolized by high-bandwidth nodes and lower the entry threshold for low-bandwidth nodes, NetFlowCoin sets four intervals for node bandwidth, and each interval corresponds to different adjustment parameters:
By introducing an regulatory factor, nodes with different bandwidths have different pre-staking NFC numbers. The larger the bandwidth, the more the number of pledges.
The greater the ability, the greater the responsibility!
4.2 The pledge should be related to the actual output of the system
The pledge needs to consider the balance between the generation capacity and the costs of nodes. When users and output are small in the early stage, a large number of pledge is required to protect the network. As the output increases later, excessive staking will affect the normal use of the network by consumers, because network traffic needs to be driven by FUL.
4.3 The pledge should be related to the scale of the network
With the increasing number of participants, the entry and exit of a small number of nodes will not harm the entire system. On the contrary, the addition of new nodes is a very useful supplement to the diversity and reliability of the network. However, the increase in network scale has led to an increase in value. It is necessary to avoid higher and higher entry barriers that hinder new followers.
On the whole, the pledge needs to combine many factors to meet the self-regulation ability in a certain period of time, so as to provide better services for ecological construction.
After NetFlowCoin integrates the cumulative output, computing scale (bandwidth scale), time and interval regulatory factors, a new flow pledge calculation formula is designed based on the unit bandwidth of different intervals:
refers to the number of NFCs that need to be pledged for the unit bandwidth mpbs of the bandwidth interval s at time t
is the cumulative NFC output of the entire network PoF
is the total network bandwidth at time t, unit: mbps
is the regulatory factor of the bandwidth interval s
s s is the bandwidth interval
In the early stage, due to the small output and computing power, the pledge amount will be too small to achieve the original design effect. NetFlowCoin uses a model that combines pledge value presets and dynamic formula calculation:
When the total network traffic is less than or equal to 1 EB, the pledge amount is based on the preset value
When the total network traffic is more than 1 EB, the traffic pledge calculation formula takes effect. There is still a judgment condition as follows:
If the calculated value of the formula is less than or equal to the preset value, the calculated value will be the pledge amount
If the calculated value of the formula is more than the preset value, the preset value will be pledge amount
When the node exits our project, you can choose to release the pledge, the pledge balance after deducting the penalty will be locked for 180 days, users can withdraw the pledge balance at one time. Once the pledge is released, it means that the node gives up the power of block generation or traffic generation.
Nodes will be slashed due to double-signatures, failures, etc. (it is forbidden to become a witness node). The specific rules are as follows:
All nodes participating in the block generation have an initial score,
a)Each time a node is absent from a block, m points will be deducted from Score(BN). If a node successfully completes a block generation, Score(BN) will be added x points (m>x).
b)When, the node cannot participate in the selection of candidate nodes (this node cannot participate in block mining)
The penalty score is persistent, and its life cycle is as same as the block generation pledge, that is, it will be reset to full marks only when the block generation pledge is completed (for example: after exiting the block generation pledge, the penalty score would be zero, and reset the score to n when re-pledge).
Nodes can purchase scores, and they must be purchased at a time to make up to the full score n, and the NFC used to purchase the scores is added to the current node’s block generation pledge. The formula for calculating the score is:
For nodes that participate in traffic generation, they will also be slashed when malicious behavior occurs. The penalties mainly include fake bandwidth and offline:
Fake bandwidth penalty
The actual bandwidth of the traffic node will be checked regularly. If it is found that the actual bandwidth of the traffic node BW(a)<the declared bandwidth BW(c), the pledge amount will be deducted BW(c)-BW(a), and the bandwidth will be reduced to BW(a).
For example: when the traffic node sam participated in pledge, the bandwidth is claimed to be 100Mbps, but the actual bandwidth is 80Mbps, the pledge amount will be deducted 100–80=20Mbps, and the bandwidth of sam will be reduced to 80Mbps (that is, the maximum daily flow of sam’s output will be reduced by 20%)
As a highly available network, NetFlowCoin hopes that all nodes involved in traffic generation can be online 7*24 hours, so as to ensure that the network can provide services to users all the time. Therefore, for offline traffic nodes, penalties will be imposed based on their offline duration.
a) If the online time of the traffic node is less than 19.2 hours per day, the node will not be able to get the reward for the day.
b) If the traffic node is offline for 24 hours, the node will not be able to get the reward for the next 7 days.
c) If a traffic node is offline for 7 days, traffic generation pledges of the node will be deducted to zero, and this node will lost the right of traffic generation.
Pledge plays a key role in the stable operation of NetFlowCoin & SDN/SDVN, which is mainly reflected in:
Improve node stickiness: pledge can effectively increase the stickiness of nodes, prevent nodes from exiting the network at random, and will not prevent new followers from joining because of excessive high value
Standardize node behavior: Punishment can prevent nodes from doing evil and also incentivize nodes to provide better services
Increase the cost of attacks by 51%
Incentive nodes to maintain network stability: pledge allows participants and the network to form a community of interests, allowing participants to make contributions to the network more rationally