the promises and challenges of ethereum off-chain scalingethis.unitimes.pro/file/1472538728349439....
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The Promises and Challenges of Ethereum Off-Chain Scaling
Xiaozhou Li Celer Network
Internet (web 2.0) vs. Ethereum (web3.0)
global information transfer global value transfer
One second:70K Google searches,millions of emails and messages, 60TB data transfer ……
One second:10 transactions
≫
global information transfer global value transfer
One second:70K Google searches,millions of emails and messages, 60TB data transfer ……
One second (goal):??? transactions
Can Ethereum match the scale of Internet?
≈
global information transfer global value transfer
One second:70K Google searches,millions of emails and messages, 60TB data transfer ……
One second (goal):hundreds of millions or billions of transactions
Can Ethereum match the scale of Internet?
≈
Billions of TPS
How could we ever get there?
Scalability
On-chain Limit
Mass Adoption
Efforts
Where we are
blockchain
dApps
blockchain
Scalability
On-chain Limit
Mass Adoption
Efforts
Where we are
off-chain scaling
dApps
How does off-chain scaling work?
off-chain transfer on-chain settle
Concepts: state channel, sidechain Only resort to on-chain consensus when absolutely necessary
Secure: blockchain acts as the “supreme court”
Fast: independent operations across nodes, fully scale-out
Private: most activities only seen by participants
Example: off-chain payment channelOn-chain bond contract
Deposi
t 10 E
THDeposit 10 ETH(2 on-chain transactions)
Example: off-chain payment channelOn-chain bond contract
(N off-chain transactions)
$X $Y#n
Balance Proof
Example: off-chain payment channelOn-chain bond contract
Subm
it sta
te pro
of
(On-chain settlement)
agree
$5
$15
#47
Example: off-chain payment channelOn-chain bond contract
disagreeSu
bmit
state
proof
(On-chain settlement)
$5
$15
#47
$2
$18
#49
Example: off-chain payment networkOpen up great opportunities for ultra high throughput p2p micro-payments
Example: off-chain chess duelOn-chain bond contract
0.1 ETH if Alice wins
0.1 ETH if Bob winsAlice Bob
Example: off-chain chess duelOn-chain bond contract
State Proof
Example: off-chain chess duelOn-chain bond contract
0.1 ETH
Win! Cooperative
Zero on-chain operations when everyone is cooperative
Example: off-chain chess duelOn-chain bond contract
Win! Uncooperative
Only resort to on-chain consensus when absolutely
necessary
Dispute
State
Proof
Bright future, challenges remain
• How to support generic operations with minimal on-chain footprint?
• How to route value transfers efficiently in off-chain networks?
• How to help developers to easily build and operate off-chain dApps?
• How to make off-chain states always available for on-chain disputes?
• How to obtain enough liquidity to run an off-chain service?
Celer Network
cStack
cEconomy
Celer ArchitectureCeler Network is an Internet-scale, trust-free, and privacy-preserving platform where everyone can quickly build, operate, and use massively scalable decentralized applications.
Blockchain
dApps
Celer Network
cChannel
cOS
cRoute
cStack
+
cEconomy
State Guardian Network
Proof of Liquidity Commitment Mining
Liquidity Backing Auction
cChannel: Generalized dApp Support
• Generic off-chain state transitions o conditional payment o multiparty gaming o second price auction o high frequency exchange o ...
• Pure off-chain contract o no on-chain deployment when everyone cooperates
• Multi-hop state relay
• Formal specification and verification
cChannel
cOS
cRoute
cStack
cChannel: Generalized dApp Support
cChannel
cOS
cRoute
cStack
on-chain stateoff-chain state state dependency
Alice will pay Bob 1 ETH if Carl
wins
Bob will pay Carl 1 ETH if Carl
wins
Alice <---> Bob Bob <---> Carl
Alice vs. Carl
cRoute: Highly Efficient Payment Routing
• Provably optimal throughput
• Transparent channel balancing
• Fully decentralized
• Failure resilience
• Privacy preservingcChannel
cOS
cRoute
cStack
Why off-chain payment routing is challenging?
• Link state changed by every payment
• Max rate ranges from zero to infinity
• Network is constantly changing
X Ybalance of
Xbalance of
Yoff-chain channel
• Link state not affected by past transmissions
• Max rate is fixed (e.g., always 1Gpbs)
• Network is relatively stable
X Ybandwidth
data network link
Off-chain payment networks are fundamentally different from data networks
Most distributed routing algorithms for data networks are hard to converge in off-chain networks
cRoute: Highly Efficient Payment Routing
cChannel
cOS
cRoute
cStack
Forwarding Layer: Distributed Balanced Routing (DBR)
Policy Layer: Flexible Policy Configuration and Enforcement
Overlay Layer: Privacy-Preserving Onion Routing
cRoute Simulation Results
77 nodes 254 bi-directional payment channel Poisson arrival with random src-dst
Payment throughput Channel utilization
cOS: Development Framework and Runtime
• Provide common design patterns
• Enable “write once, run anywhere”
• Bridge on-chain and off-chain byte code
• Figure out state dependencies
• Track and dispute off-chain states
• Support concurrent off-chain dApps
cChannel
cOS
cRoute
cStack
cOS: Development Framework and Runtime
cChannel
cOS
cRoute
cStack
Scalability does not come for free!
Off-chain scaling is introducing new tradeoffs
Bright future, challenges remain
• How to support generic operations with minimal on-chain footprint?
• How to route value transfers efficiently in off-chain networks?
• How to help developers to easily build and operate off-chain dApps?
• How to make off-chain states always available for on-chain disputes?
• How to obtain enough liquidity to run an off-chain service?
Celer Network
cStack
cEconomy
cEconomy completes the off-chain ecosystem
State Guardian Network
Proof of Liquidity Commitment Mining
Liquidity Backing Auction
disagree
Settl
e
sync
Offline
$5$1
5
#47
$2 $18#49
Ensure off-chain states are always available for on-chain disputes
State Guardian Network
Proof of Liquidity Commitment Mining
Liquidity Backing Auction• Off-chain service providers crowdsource liquidity • Reward committed liquidity backers • Ensure 100% safety for end users
cEconomy completes the off-chain ecosystem
Incentivize an abundant and stable liquidity pool
Build and operate Internet-scale dApps on Celer Network
Blockchain
dApps
Celer Network
cChannel
cOS
cRoute
cStack
+
cEconomy
State Guardian Network
Proof of Liquidity Commitment Mining
Liquidity Backing Auction
Thanks!www.celer.network