谁发起领导人选举

Question

Who initiates the leader election in a peer to peer network with no leader?. Here is some code that i implemented when receiving messages.

if (message.startsWith(ELECTION)) {
        int recievedID = Integer.parseInt(ripMessage(ELECTION, message));
        if (processID > recievedID) {
            sendToAll(ELECTION + processID);
        } else if (processID < recievedID) {
            sendToAll(ACKNOWLEDGE);
        }
    } else if (message.startsWith(ACKNOWLEDGE)) {
        ackRecv++;
        if (connections.size() == ackRecv) {
            connection.sendMessage(LEADER + processID);
            this.isLeader = true;
            this.leaderID = processID;
            ackRecv = 0;
        }
    } else if (message.startsWith(LEADER)) {
        int recievedID = Integer.parseInt(ripMessage(LEADER, message));
        this.leaderID = recievedID;
        this.isLeader = false;
    }

Answer 1

Normally in a peer-to-peer system, there would be no leader.

In such cases leader election does not make sense.

There are various peer-to-peer algorithms - for example Chord .

Answer 2

Check out Paxos consensus algorithm . The algorithm itself likely overkill for P2P cases... still may be useful as list of issues you need to address.

Super short version - most of participants (quorum) must agree on election message {leader, version} with highest version. Multiple rounds may be necessary if multiple elections started at about the same time.