Effects of a Simple Relay Network on the Bitcoin Network
Kai Otsuki

Yusuke Aoki

Tokyo Institute of Technology
Tokyo, Japan
ootuki.k.aa@m.titech.ac.jp

Tokyo Institute of Technology
Tokyo, Japan

Ryohei Banno

Kazuyuki Shudo

Tokyo Institute of Technology
Tokyo, Japanbanno@computer.org

Tokyo Institute of Technology
Tokyo, Japan
shudo@is.titech.ac.jp

ABSTRACT

1

Bitcoin has a low transaction throughput. In order to allow for
an increase of this throughput without increasing orphan blocks,
decreasing the block propagation time is important. One of thetechniques to improve its block propagation time is to utilize relay
networks. However, the effects of utilizing relay networks is notapparent. Existing studies and measurements on relay networks
have not focused on the effect of relay networks on the individual
miners. Moreover, the relation between the degree of the effect andrelay network utilization rate is unknown. Herein, we performed
simulations while finely changing the proportion of nodes utilizinga relay network. Moreover we quantitatively evaluated the effect ofrelay networks on the entire Bitcoin network and individual miners.
Results show that the propagation time decrease to approximately
77% of the original value if the utilization rate is set to 3%. This rate
is close to the actual utilization rate of relay network "Falcon". We
also found that the probability of blocks created by utilizing nodes
to become orphan blocks is surprisingly smaller than that of the
non-utilizing nodes. Even in the worst case, the value of utilizing
nodes is 15% of the value of non-utilizing nodes.

Several blockchains such as Bitcoin have fault tolerance and makeit possible to manage distributed ledger information without aspecific management entity even when multiple malicious nodes
are present [11]. Although Bitcoin possesses these advantages, it
has some limitations. A low transaction throughput is one of thebiggest problems of Bitcoin. The transaction throughput is thenumber of transactions that a system can process within a certain
time. At most, Bitcoin’s throughput is 7 TPS owing to its design.
In comparison, this value is below Visa’s and PayPal’s averagethroughput of 1700 TPS [6] and 290 TPS [5] , respectively. It meansthat Bitcoin can’t support a system with the same scale as thesecentralized systems.
Shortening of the block interval is essential to increase thethroughput. However, it is still difficult to simply shorten the blockinterval because the interval is set as the time essential for a block
to be spread sufficiently within the network. In addition, A shorter
block interval can cause more orphan blocks [12], which means a occurrence of a fork, and greatly damages the security of a blockchain
network and the consistency of the ledger. To improve the throughput while avoiding an increase in orphan blocks, an increase in
the block propagation speed is essential[8]. In other words, sufficient block propagation speed improvement safely achieve a shorter
block interval.
An effective method to increase the block propagation speed is
to utilize a relay network (cf. Figure 1), formed by a group of nodes
that is capable of initiating a fast block distribution. Nodes using
a relay network can send a block to other utilizing nodes simultaneously. Fast internet Bitcoin relay engine (FIBRE) and Falcon are
relay networks used in Bitcoin. Falcon [3] is developed by Cornell
University’s research team, and FIBRE is a relay network developedby Matt Corallo, one of the developers of Bitcoin Core/citecore.
Presently, it is unclear what effect relay networks have on the Bitcoin network and individual miners. Existing measurements doneby these relay network operators are partial because they measurereal data. Moreover, no studies have measured the effect of relay
networks while finely changing a utilization rate in a relay network,
the proportion of blockchain nodes utilizing a relay network, and nostudies has also paid attention to the influence on individual miners.
Herein, we simulated while changing the utilization rate in a relay
network. We quantitatively evaluated blockchain network-leveland miner-level effects. As the blockchain network-level effect, weinvestigated the effect on the Bitcoin network such as the orphan

CCS CONCEPTS• Networks → Peer-to-peer networks.

KEYWORDS
relay network, bitcoin network, blockchain
ACM Reference Format:
Kai Otsuki, Yusuke Aoki, Ryohei Banno, and Kazuyuki Shudo. 2019. Effects
of a Simple Relay Network on the Bitcoin Network. In Asian Internet Engineering Conference (AINTEC ’19), August 7–9, 2019, Phuket, Thailand. ACM,
New York, NY, USA, 6 pages. https://doi.org/10.1145/3340422.3343640

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INTRODUCTION

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K. Otsuki et al.

Relay network

2

Relay server

Node

BITCOIN NETWORKIn this section, we explain our research background. We look attransaction handling in the Bitcoin system and describe problemsof transaction confirmation. Finally, we refer to relay networks in
Bitcoin.

2.1

Handling transactions in Bitcoin

We look at the flow from transaction issues to confirmation oftransactions of the Bitcoin system. Then, we focus on orphan blocks.

Blockchain network
Figure 1: Relation between relay network and blockchain
network: A relay network is an external network of a
blockchain network. The relay network is composed of relay
servers, and the blockchain network consists of blockchain
nodes. Each Node utilizing the relay network can send andreceive blocks to/from the relay server.

block rate. Also, we examined the effect on individual miners suchas mining success rate.
Knowing the relation between the relay network effect on a
blockchain network and a utilization rate in a relay network helps
to understand usefulness of relay networks for throughput improvement. By understanding the effect on each miner, we can know if
there is an incentive to use a relay network for miners.
The summary of our findings is as follows:• The block propagation time improves as the utilization rate
in a relay network increases. When the utilization rate is3%, which is close to actual relay networks utilization rate,
the propagation time is reduced to approximately 77% of theoriginal value.
• A relay network decreases the orphan block rate, and whenhalf of the nodes join the relay network, the value is reduced
to less than 15% of the original value.
• In any utilization rate in a relay network, there is almost no
difference in the number of discovered blocks between nonutilizing and utilizing nodes. In other words, relay networks
have little impact on mining success rate.
• Nodes utilizing a relay network have a surprisingly low probability of creating orphan blocks compared to non-utilizing
nodes. Remarkably, even in the worst case, the value of utilizing nodes is approximately 13% of the value of non-utilizing
nodes.
The rest of this paper is organized as follows. In Section 2, as background knowledge, we describe the transaction handling in Bitcoin
and the problems associated with it, and then we will look at arelay network that is one of the approaches to decrease the blockpropagation time. In Section 3, we describe a simulator and modelsof the Bitcoin network and a relay network used in this study. In
section 4, we present our experimental results. In Section 5, weoverview related work, and we conclude the paper in Section 6.

2.1.1 Transaction issue. A transaction is recorded in a distributed
ledger called a blockchain. When a node attempts to send coins
to someone, it issues a transaction and broadcasts the transaction
over the Bitcoin network. When nodes receive it, they verify it.
If the transaction is valid, it will be stored in a memory called atransaction pool.
2.1.2 Block creation. To create a block containing the pooled transactions, miners repeat the hash calculation until they find a hashvalue that meets certain criteria. This process is called proof of work
(PoW) and prevents invalid blocks from being generated. Whennodes succeed in mining a block, they broadcast the block acrossthe network and can obtain mining rewards. Basically, miners join
the Bitcoin network in search of rewards.
2.1.3 Transaction confirmation. When nodes receive a block, they
verify it. They add the block to their ledgers if it is valid. At this stage,
the transactions contained in the newly added block are confirmed.
A distributed ledger held by each node is a chain from the first
generated block to the current block, which is a huge transaction
register. A block is generated by using a hash value of the previous
block, and it decides the order of blocks and the continuity of theledger is guaranteed.
2.1.4 Orphan block. Forks are defined as the situations where aledger is branching and they occur when a plurality of blocks areadded after the same block. When a fork occurs in Bitcoin, thebranch with the largest number of blocks is adopted as a formal
ledger. At this time, the blocks in the pruned branches becomeorphan blocks.
Presence of forks is a big problem because it means that nodes
with different ledgers exist on the blockchain network and transaction consistency among such nodes is temporarily lost. In addition,transactions in an orphan block are invalid, and computational
resources for an orphan block creation are wasted.

2.2

Problems in Bitcoin

2.2.1 Problem Regarding Confirmation Time. A Transaction is confirmed when the block including it is confirmed. In Bitcoin, the blockinterval is set to 10 min [1]. Since It is considered that transactions
are not overwhelmed if the six blocks are confirmed. Therefore,
the time of six blocks confirmation is required to ensure that thetransactions are definitely valid. The property becomes a crucial
problem in trades having a deadline such as auctions or trades
whose price fluctuate within seconds such as currency transactions.
To overcome the problem, a reduction in the 10-minute block interval is required. However, achieving this reduction is difficult
as a fork occurs when another node generates a block before a

Proc. 15th Asian Internet Engineering Conference(AINTEC 2019), August 2019

Effects of a Simple Relay Network on the Bitcoin Network

AINTEC ’19, August 7–9, 2019, Phuket, Thailand
Table 1: Summary of each relay network.

block propagates sufficiently. To reduce the block interval while
suppressing the orphan block rate, an improvement of the blockpropagation time is necessary.
2.2.2 Problem regarding throughput. A throughput which is defined by the number of transactions which can be received fromusers could be improved in proportion to the increase in the numberof nodes. The problem here is the transaction throughput.
The upper limit of Bitcoin’s transaction throughput is approximately 7 TPS as the upper limit of the number of transactions included in a block is about 4000 and the block interval is 10 minutes.
This is much smaller than the values such as Visa’s and PayPal’s average throughput of 1700 TPS and 290 TPS, respectively. Since thesenumbers are average values, much larger throughput is required at
its peak.
The transaction throughput is determined by the number oftransactions in a block divided by the block interval. Two schemes
for improving the throughput are available. One is to increase theblock size and the second is to reduce the block interval. Basically,
the former does not contribute to the improvement because anincrease in the block interval is necessary to suppress the fork when
the block size increases. As a result, the improvement is canceledout. To perform the latter without increasing the orphan block rate,
it is necessary to reduce the propagation time as mentioned earlier.

2.3

Relay networks

Utilizing relay networks is a method to improve the propagation
time. Blockchain networks are not always suitable for efficient
block distribution because they have other issues to deal with, suchas malicious nodes. The relay network is a network suitable for
efficient block distribution and can perform more efficient blockpropagation than a blockchain network.
Next, we describe the overview of block distribution using relay
networks (cf. Figure 1). Relay networks are constructed outside the
Bitcoin network ,and speed-up methods used in relay networks
differ depending on its implementations. However relay networks
have roughly the same basic structure. The flow of the block distribution is roughly as follows: First, relay servers constituting a relay
network have been arranged all over the world. A node utilizing
the relay network transmits blocks to the relay server in the same
area. Then, the blocks propagate throughout the relay network, andutilizing nodes get the block from relay servers in the same area.
Several Bitcoin relay network projects are avilable and theseinclude Bitcoin Fast Relay Network (BFRN) [2], Falcon [3], Fast
Internet Bitcoin Relay Engine (FIBRE) [4] and bloXroute [10]. We
briefly summarize their characteristics below and in Table 1.
Bitcoin Fast Relay Network (BFRN)
BFRN is the first Bitcoin relay network,which was set up by
Matt Corallo in 2014. It has nine servers scattered aroundtshe world. This relay network has been shut down and is
not currently in operation.
FalconFalcon was launched in 2016 by a Cornell University researchteam. They use a cut-through routing as the fast block propagation method. This relay network consists of ten servers
around the globe.

Project
BFRN
FalconFIBRE
bloXroute

Year
2014
2016
2016
2018

Number of servers
8
10
6
Unknown

Developer
Matt Corallo et al.
Cornell University
Matt Corallo et al.
Cornell University

Fast Internet Bitcoin Relay Engine (FIBRE)
FIBRE was developed by Matt Corallo in 2016 and has aunique UDP based relay protocol. It has six servers aroundthe world. This relay network is especially designed for compact blocks, a relatively new relay protocol in Bitcoin.
bloXroutebloXroute is a recent relay network. It published a white
paper in 2018. However it is not yet in operation. Several
developers of Falcon are involved in this relay network, andthey focus on the existing relay networks problem that nodes
using relay networks have to trust the relay networks.

3

SIMULATING RELAY NETWORKSIn this section we refer to the simulator used in our experiments.
Then we introduce our models of the Bitcoin network and a relay
network.

3.1

Simulator

We performed experiments using the simulator to investigate theeffect of relay networks. The advantages of using a simulator are
as follows.
• A simulator makes it possible to acquire the data of eachnode and the structure of the network, which are difficult toobtain from the actual network.
• The cost of setting up and implementing a simulator is lower
than that of preparing an experimental private network.
• With a simulator, it is possible to freely set parameters suchas hash power and a utilization rate in a relay network.
In this research, we used a blockchain simulator SimBlock [7].
Because SimBlock can simulate a situation where an inter-nodedelay fluctuates, it is suitable for measuring the effect of relay
networks.

3.2

Blockchain Network ModelFirst, we are going to look at the parameters of this blockchain
simulator and its settings.
In our experiments, the unlisted parts of parameters simulate
the Bitcoin environment in 2015 examined by Gervais et al. [9]. The
parameters in Table 2 were used by Aoki et al [7] except for hashpower. To compare the mining success rates of nodes utilizing arelay network and non-utilizing nodes, we set the hash power of
all nodes uniformly.
In this simulator, each node has an upstream bandwidth and adownstream bandwidth, and the transmission time is determined
as follows.
T r ansmissionT ime = Del ay +BlockSize+ P r ocessinдT ime
Bandwidt hProc. 15th Asian Internet Engineering Conference(AINTEC 2019), August 2019

AINTEC ’19, August 7–9, 2019, Phuket, Thailand

K. Otsuki et al.

Table 2: Parameter settings of blockchain network.
# of nodes
Block interval
Block size
Hash power
Geographical Distribution
Bandwidth
Delay

6000
10 min534 KiB
Uniform
Distribution according to Bitcoin
6 regional bandwidth
6 regional propagation delay

Our model

Actual relay networks
Region A

Region B

Region A

Region B

Figure 3: Median block propagation time.
Blocks are sent at 10x an upward
bandwidth of the sender.

Figure 2: Actual relay networks and our simple relay network model.
Bandwidth = min{U pst r eam Bandwidth of a Sender,
Downst r eam Bandwidth of a Receiver }The delay is determined by the region of a sending node, region ofa receiving node, and random number. Moreover, the processing
time represents a time required to validate a block.

3.3

Our Simple Relay Network Model

We will introduce our simple relay network model. Herein, we aim
to investigate the effect of relay networks rather than a specific relay
network. Therefore, we used a relay network model that abstracts
and simplifies the actual relay networks. Before explaining our relay
network model in detail, we review how the actual relay networks
work.
Relay server communication is generally faster than a ordinaryinter-node communication because relay networks use methods
like cut-through routing, optimization of its topology and so on totransmit blocks faster, and they are likely to have large bandwidth.
When a node utilizing a relay network sends blocks to the relay
server in the same area, and the relay server broadcast the blocks
to its relay network and other utilizing nodes can get the blocks
from relay servers.
Then, in our relay network, we assume that nodes utilizing therelay network can transmit blocks to the other utilizing nodes
by using 10 times their original upstream bandwidths. The Fig. 2
shows this. Thus, this simple relay network enable nodes to transmit
blocks to other nodes directly or with one hop. Since downstream
bandwidths are sufficiently larger than upstream bandwidths, theimprovement in the upstream bandwidths help to make full use of
the downstream bandwidths.

In this experiment, we changed the utilization rate in the relay
network. The utilization rate represents the proportion of blockchain
nodes using a relay network. We performed the experiments at utilization rates of 0%, 1%, 2%, 3%, 5%, 10%, 25%, 50% and 100%. We
focused on low utilization rates considering the utilization rate ofreal relay networks. For example, from the data collected on January 27, 2019, Falcon utilization rate is 2.65%. Also, We randomly
selected the utilizing nodes.

4

EXPERIMENTAL RESULTS

Two effects of relay networks are the blockchain-network-level effect and the miner-level effect. Herein, we examined the two effects
and each simulation was run independently for 10000 consecutive
blocks.

4.1

Effects on blockchain network

We use median block propagation time and orphan block rate tomeasure the relay network influence on the Bitcoin network.
4.1.1 Block propagation time. The effects of relay networks onblock propagation time are discussed. We measured the medianblock propagation time for three groups of nodes, namely, all nodes
in the Bitcoin network, the nodes utilizing the relay network, andthe nodes not utilizing the relay network. All nodes consist of thenodes utilizing and not utilizing the relay network. The results areshown in Fig. 3.
We observe that the block propagation time for the Bitcoin network improves as the utilization rate in the relay network increases.
This shows that using relay networks leads to an improvement in
the propagation time. Even if the utilization rate is 3%, which is
close to the actual relay network utilization rate, the propagation
time is reduced to approximately 77% of the original value. Moreover, we observe that the propagation time improves in proportion
to the utilization rate, even when observing each of the utilizing
nodes and non-utilizing nodes separately. In other words, relay networks also improve the propagation time for non-utilizing nodes.

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Effects of a Simple Relay Network on the Bitcoin Network

Figure 4: Orphan block rate.

AINTEC ’19, August 7–9, 2019, Phuket, Thailand

Figure 5: Average number of discovered blocks.

Also, we can see that the median of the block propagation time ofutilizing nodes has been always lower than that to non-utilizing
nodes.
4.1.2 Orphan Block Rate. We investigate the effect of relay networks on the orphan block rate. Fig. 4 shows the orphan block rates
in each utilization rate.
We see that the orphan block rate decreases as the utilization
rate in the relay network increases. With a utilization rate of 3%,
the orphan block rate improve to approximately 85% of the initialvalue, and when half of the nodes join the relay network, the value
is reduced to less than 15% of the original value.
An improvement in the block propagation time contributes tothis decrease because a shorter block propagation time decreases
the orphan block rate and the relay network decreases the time as
the Fig. 3 shows.

4.2

Effects on each miner

We measured the average number of discovered blocks and the
proportion of orphan blocks in all discovered blocks for utilizing
and non-utilizing nodes to understand the influence on individual
miners. Our experimental results are as follows:
4.2.1 Mining success rate. We investigate whether relay networks
affect mining. In Fig. 5, we compare the average discovered blocknumbers of utilizing and non-utilizing nodes. Note that the numberof discovered blocks does not include blocks that become orphan
blocks and only blocks that are included in the longest chain of theblockchain are counted.
We observe that the relay network has a little effect on mining
and no difference in the number of discovered blocks between utilizing and non-utilizing nodes. Moreover, the numbers of successful
mining of utilizing and non-utilizing nodes are higher or lower
regardless of the utilization rate.
Hash power and time to start mining determine a great part ofmining success. In this experiments, we assume that all nodes havethe same hash power. Thus, we can say that the improvement of

Figure 6: Rate of the number of orphan blocks for the number of discovered blocks.

the block propagation time produced by the relay network is notenough. Since our simulations use a strong relay network model,
the mining success difference between utilizing and non-utilizing
nodes is smaller for an actual relay network.
4.2.2 Proportion of Orphan Blocks. We investigated other relay
network influence on each miner in addition to the mining successrate. We show the rate of the number of orphan blocks for thenumber of blocks discovered by utilizing nodes and non-utilizing
nodes in Fig. 6. In Fig. 4, we focused on the relay network impact
on orphan blocks for all the nodes on the Bitcoin network, and wethen focus on the impact on orphan blocks for nodes utilizing andnodes not utilizing the relay network.
Our results show that utilizing nodes have a much lower probability of creating orphan blocks than non-utilizing nodes, regardlessProc. 15th Asian Internet Engineering Conference(AINTEC 2019), August 2019

AINTEC ’19, August 7–9, 2019, Phuket, Thailandof the utilization rate. Even when the utilization rate is 50%, whichis the case where the difference between the two is the smallest,
the value of utilizing nodes is approximately 13% of non-utilizing
nodes. The 25% utilization rate is the best case and the former value
is approximately 3 % of the latter value. Note that this difference istrue even if the utilization rate in the relay network is lower than
the actual utilization rate such as 1% and 2%.
This shows that utilizing a relay network allow miners to put
their created blocks on the longest chain. Therefore, this newly
discovered effect shows miners an incentive to use relay networks.

5model assumed in this research is a simplified model and the propagation protocol is assumed to be of the 2015 model, which is thesame setting developed by Gervais [9]. After further refining therelay network model, we would like to evaluate the effectiveness ofrelay networks under new propagation protocols such as compact
blocks. Herein, we assume that upstream bandwidth is 10 times
as a strong relay network model and we intend to investigate therelation between relay network performance and its effect, such as
how the results would change if the bandwidth is doubled, threetimes, and so on.

7

RELATED WORK

Measurements on relay networks have not been widely investigated.
In this Section, we refer to measurement values by operators ofeach relay network [2–4] and the research by Gervais [9].
Relay network operators publish measured values, for instanceblock propagation time to nodes utilizing a relay network or number of blocks discovered by utilizing nodes whose IP addresses
are known. They can only make measurements on relay servers
and utilizing nodes because these values are actual data. In otherwords, they cannot compare data between utilising nodes and nonutilizing nodes. We performed measurements by simulation, so
we can obtain data on the whole, not part, and also compared thedifference between utilizing and non-utilizing nodes.
Gervais discussed the security of PoW blockchains and did notcover the miner-level effect. They measured the effect on the blockchain
network such as the orphan block rate and the median block propagation time. But they conducted experiments only when the utilization rate of a relay network is 0% and 100%. Since BFRN only
existed at that time, they only considered BFRN as a relay network.
In this research, we aimed to investigate the effect of relay networks
rather than a specific relay network. Moreover, we measured thedata while changing the utilization rate to 0%, 1%, 2%, 3%, 5%, 10%,25%, 50%, and 100%.

6

K. Otsuki et al.

ACKNOWLEDGMENT

This work was supported by SECOM Science and Technology Foundation.

REFERENCES[1] [n. d.]. Bitcoin Core : Bitcoin. https://bitcoincore.org. accessed Jan. 28, 2019.
[2] [n. d.]. Bitcoin Relay Network. http://bitcoinrelaynetwork.org/.
[3] [n. d.]. Falcon - A Fast Bitcoin Backbone. https://www.falcon-net.org/. accessed
Jan. 27, 2019.
[4] [n. d.]. FIBRE Fast Internet Bitcoin Relay Engine. www.bitcoinfibre.org/. accessed
Jan. 28, 2019.
[5] [n. d.].
PayPal Reports Second Quarter 2018 Results | PayPal, Inc.
https://investor.paypal-corp.com/news-releases/news-release-details/
paypal-reports-second-quarter-2018-results?ReleaseID=1072972. accessed Jan.
28, 2019.
[6] [n. d.]. VisaNet | Electronic Payments Network. https://usa.visa.com/about-visa/
visanet.html. accessed Jan. 28, 2019.
[7] Yusuke Aoki, Kai Otsuki, Takeshi Kaneko, Ryohei Banno, and Kazuyuki Shudo.
2019. SimBlock: A Blockchain Network Simulator. In Proc. CryBlock 2019 (in conj.
with INFOCOM 2019).
[8] Christian Decker and Roger Wattenhofer. 2013. Information propagation in the
Bitcoin network. In Proc. IEEE P2P 2013. IEEE, pp.1–10.
[9] Arthur Gervais, Ghassan O Karame, Karl Wüst, Vasileios Glykantzis, Hubert
Ritzdorf, and Srdjan Capkun. 2016. On the security and performance of proof ofwork blockchains. In Proc. ACM CCS 2016. ACM, pp.3–16.
[10] Uri Klarman, Soumya Basu, Aleksandar Kuzmanovic, and Emin Gün Sirer. 2018.
bloXroute: A Scalable Trustless Blockchain Distribution Network WHITEPAPER.
[11] Satoshi Nakamoto et al. 2008. Bitcoin: A peer-to-peer electronic cash system.
[12] Yonatan Sompolinsky and Aviv Zohar. 2015. Secure high-rate transaction processing in bitcoin. In International Conference on Financial Cryptography andData Security. Springer, pp.507–527.

CONCLUSION

Herein, we investigated the blockchain-network-level and minerlevel effect of relay networks quantitatively while changing a utilization rate in the relay network. Regarding the effect on theblockchain network, we found that relay networks improve theblock propagation time and reduce the orphan block rate. These
effects become stronger as utilization rate in the relay network
increases. Also, for individual miners, we saw that relay networks
do not affect the mining success rate, but they significantly affect the probability of creating orphan blocks. utilizing nodes are
surprisingly less likely to create orphan blocks than non-utilizing
nodes.
These results help to understand the effectiveness of a relay network in improving blockchain scalability. If the effect is considered
to be above a certain level, the results will motivate the development of relay networks. Our results show that there is an incentive
to use a relay network for individual miners and help miners todecide whether to use a relay network.
We plan to investigate the influence of relay networks on otherblockchain networks such as Ethereum. Also, the relay network

Proc. 15th Asian Internet Engineering Conference(AINTEC 2019), August 2019