Questions tagged [consensus]
The consensus tag has no usage guidance.
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Are vote messages sent broadcast in federated voting, regardless to slices?
In the federated voting phase of SCP are vote messages transmitted to all nodes in the network, regardless of slices?
Example : if we have 2 nodes A and B, where A includes B in one of its quorum ...
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The Balloting protocol of SCP - Step 9
The Paper on SCP at https://pdfs.semanticscholar.org/3bab/b89369eed603ce3c702f447ee6274429cda1.pdf?_ga=2.113216397.862297418.1585318681-2089854760.1525259881, describe the concrete balloting protocol ...
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Unable to find 5 sec slot timing in code base
I was trying to understand the stellar code base and was looking for a place where 5 sec slot timing is hardcoded (if I am not wrong). But unable to find that, instead in ovalayManagerImpl.cpp file I ...
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SCP Safety Guarantee Question
I have a question regarding the Stellar Consensus Protocol. In the SCP whitepaper it is stated on page 14 under the point 5.4 "Accepting is not enough": "But as discussed in Section 4.1, the only ...
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pBFT in closed 100 node setup
Can Practical Byzantine Fault Tolerance (pBFT) be considered as one of the quorum configurations of SCP of stellar? I am considering the situation where the 100 nodes are run in a closed network.
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How does a stellar node know that node its communicating with is definitively in or outside its quorum group?
In order for SCP to function properly, a given node has to know that a quorum related message originated from a node in its quorum set.
How does this node know for a fact that the message originated ...
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What is the difference between FAILURE_SAFETY and QUORUM_THRESHOLD?
My assumption is that FAILURE_SAFETY refers to how many nodes in your quorum slice you allow to fail while QUORUM_THRESHOLD refers to the percentage of nodes in an quorum that's necessary to come to a ...
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`LEDGER_MAX_TX_SIZE` and `5` seconds `EXP_LEDGER_TIMESPAN_SECONDS` gives only `20` tx per second?
It seems like the consensus nomination period is set to 5 seconds and each ledger size is maximized at 100 transactions per ledger, so that would give 20 transactions per second at best.
Am I ...
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When a lower tier quorum comes to its own consensus
Consider this simple scenario:
A <--- B
A.QUORUM_SET = [A]
A.THRESHOLD = 100
B.QUORUM_SET = [A,B]
B.THRESHOLD = 49
So A is a higher tier node that comes to consensus with itself. B is a lower ...
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White paper hashing clarification
On page 20 of the Stellar Consensus Protocol white paper the specifics of calculating a weighting for other nodes, the neighbours of a node and the priority of another node are all described. ...
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Difference between full & basic validators
I'm not clear on the differences between full validators and basic validators on a network. Taken from official doc, it seems like the differences are mostly an abstraction, with full validators being ...
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Could consensus period be changed?
I'm trying to run a private network and so modifying stellar-core's source code is not out of the question. I noticed that the network is right now configured to come to consensus every 5 seconds, ...
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Does each node maintain a global ledger?
Consider in the simplest case with two disjoint quorums A and B. If something comes to a consensus in A, does B get the update as well?
On a high level view, does each peer on the Stellar network ...
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Who creates the ballot?
If I understand this correctly, when a voting is initiated, there's a ballot that holds all the values for which the network is voting on, and it gets propagated to other nodes through the consensus. ...
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How can cyclic quorum ever come to a consensus?
Consider the simplest case with three nodes A, B, C, with:
Q(A) = {{A,B}}
Q(B) = {{B,C}}
Q(C) = {{C,A}}
So a cyclic graph. How can this ever reach consensus? In order for A to make a decision, he ...
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Is Stellar platform a blockchain?
I heard Stellar is a Ripple fork, is that right?
Since Ripple does not uses a blockchain, does Stellar use a blockchain?
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Nominate --> Prepare --> Commit --> Externalize question
Ok, so I am trying to grok how, if at all, state moves through this setup.
Let's say a stellar node receives a transaction from a client that it wants to propose to the network. The node then sends ...
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Is there a minimal implementation of Stellar Consensus Protocol besides stellar-core?
I'm learning about consensus and I'd like to explore SCP in depth. However, the stellar-core implementation is difficult for a newcomer to grok. Is there a minimal SCP implementation elsewhere I can ...
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Is the Stellar Consensus Protocol paper peer reviewed?
Is the stellar consensus protocol peer reviewed?
If yes, could you share some resources pointing to the peer review?
If not, what would need to happen to have a peer review of this part of the ...
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What is asymptotic security and why does Stellar, but not POW exhibit this?
One of the benefits mentioned of SCP in comparison to POW is 'asymptotic security' https://www.stellar.org/blog/stellar-consensus-protocol-proof-code/. What does this form of security mean in practice ...
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Questions about SCP and federated voting steps, with a focus on the Internet-Draft
I recently have studied the Stellar Consensus Protocol (SCP) based on the internet draft here: https://datatracker.ietf.org/doc/draft-mazieres-dinrg-scp/.
I have several questions as follows.
In the ...
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Should Every Node Contain The Same Quorum Set Configuration?
Suppose I want to set up four nodes: A, B, C, D. I want A to trust B, and C to trust D, so the set is denoted by {{A, b}, {C, D}}.
I want to set up a situation where either one of these sets can vote ...
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Stellar failure safety with UNSAFE_QUORUM false
Stellar failure safety is defined as n = 3f+1 <=> f = (n-1)/3 n is number of node and f is failure safety.
I have setup 3 nodes with my quorum and THRESHOLD_PERCENT=67 but it is not ...
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How does the Stellar Network prevent an actor with small quorum intersection from halting the network
I am thinking through some of the edge cases of adversaries attempting to compromise the Stellar Network.
Let's say an adversary creates four consensus bearing Stellar-core nodes and runs all four of ...
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How can I query or visualize the quorum slices of the Stellar network?
I think I remember faintly that a while ago there was a JS-based visualization of the quorums between various validators on Stellar but I seem unable to find it again.
As far as I understand the ...
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How are timestamps deemed invalid?
The Stellar Consensus Protocol orders block candidates (via ballots) by the maximum timestamp and union of their transactions. It says that "values [transactions/ballots] with invalid timestamps will ...
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Is Stellar permissionless or permissioned blockchain?
Is Stellar permissionless or permissioned blockchain?
or rather (whichever is more adequate)
Is SCP permissionless or permissioned consensus protocol?
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Is there a simplified or abridged version of the Mazieres paper describing the Stellar Consensus Protocol?
Is there a simplified document describing the Stellar Consensus Protocol that is more accessible and can be understood by the general public?
I am trying to clarify and simplify the knowledge around ...
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Is Stellar Ledger immutable?
Typical mining guarantees that it is too difficult to recalculate block hashes, therefore, the ledger is practically immutable.
How does Stellar ledger achieve immutability? If it does.
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When is a slot created in the Stellar Consensus Protocol?
At what time during the protocol is a unique slot created for the nodes to vote on?
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How are changes in the stellar protocol implemented?
Recently there was a lowering of the base fee from 10 to 0.5 lumens. Typically in a blockchain such a change would require a hard fork. How did all the validators agree to accept the new limit? Did ...
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How is node membership handled on Stellar?
I'm looking through the whitepaper and getting a bit confused on an issue.
(3.2 Examples and discussion) mentions a tiered structural approach similar to the Internet with various Tier 1 nodes run by ...
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How does the Stellar Consensus Protocol prevent Sybil attacks?
A Sybil attack is an attack where a single adversary controls multiple nodes on a network in order to influence voting to their advantage. It is unknown to the rest of the network that the nodes are ...
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Are there any known weaknesses in the Stellar Consensus Protocol?
Are there any known situations, although infrequent or difficult to meet, where the Stellar Consensus protocol could not work well or where the network can be attacked by malicious nodes?
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How are the Stellar (XLM) and Ripple (XRP) protocols different?
How are the Stellar Consensus Protocol and the XRP Ledger Consensus Process different, and what does it mean for users?
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