Outbound connection success rates of a Bitcoin node

[b10c]

For the simulation, we are primarily looking for a realistic success rate of IPv4 and IPv6 connections. This allows us to simulate a node picking an address, “attempting” a connection to it, and then either succeeding or failing. When we fail, we “attempt“ another connection. Additionally, we want a success rate that ignores feelers, as feelers are only made to connections from the addrman new table (addresses we’ve never tried before). These are expected to be worse than connections to the tried table (addresses we’ve tried before).

src/net.cpp

For IPv4, we have this data from node Alice, which generally seems to perform very similar to the other nodes:

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By network and connection type

Looking at, for example, the success rate of alice’s IPv4 connections, shows that both block-relay-only and outbound-full-relay connections share the same ~25% percent success rate.

We can probably get close to reality assuming a 25% connection attempt success rate for IPv4.

However, we don’t have the same data for IPv6 yet. Node jade is not running with net: extend log message to include attempted connection type · bitcoin/bitcoin@67696b2 · GitHub and I don’t have historical data on it yet. Given that:

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Only jade makes connections to IPv6. There, we have connection success rate just above 20%.

matches the numbers for IPv4:

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All nodes can make connections via IPv4. Between 2025-01 and 2025-03-31, the nodes averaged at about a 20% (or slightly more) connection success rate.

we could assume a 25% success rate for IPv6 non-feeler connections too.