You can select your own circuit length.

How? The tech intro on the website describe tunnels (https://www.i2p2.de/techintro.html) with 3 parts.

#1 is Alice the sender or Bob the receiver

#2 is a participant

#3 endpoint gateway

Two such tunnels are used when Alice and bob communicate, for a total of 4 nodes for the communication between alice and bob.

With tor hidden services, it is the exact same scheme, but with 4 nodes per tunnel rather than 3. (or 3 nodes rather than 2 if you do not want to count alice/bob as nodes). In total, 6 nodes between is used for the alice and bob communication. (https://www.torproject.org/docs/hidden-services.html.en)

Please explain how this is incorrect. Is the tunnels as describe the I2P documentation just illustrations of how an tunnel might look like, but isn't actually how it is in practice? How does it solve the problem that tor fixes with guard nodes (as this is the context in the above comments and article)?

I am much interesting in I2P, but the above details/questions has held me back.

You can have more than 1 participating hop

Let's say we have Alice and Bob, alice wants to have 4 hops both outbound and inbound and Bob wants to have a 2 hop inbound and a 1 hop outbound

Alice's tunnels would be:

Alice -> Participant A1 -> Participant A2 -> Participant A3 -> Outbound Endpoint 1 -> ?

Alice <- Participant A4 <- Participant A5 <- Participant A6 <- Inbound Gateway 1 <- ?

Bob's tunnels would be:

Bob -> Outbound Gateway 2 -> ?

Bob <- Participant B1 <- Inbound Gateway 2 <- ?

For Alice to send to Bob and receive a reply the round trip path of the message would take would be

Alice -> PA1 -> PA2 -> PA3 -> OBEP1 -> IBGW2 -> PB1 -> Bob -> OBEP2 -> IBGW1 -> PA6 -> PA5 -> PA4 -> Alice

Since the above techintro documentation seems contradicting, I looked around and found a better page at http://www.i2p2.de/how_tunnelrouting.html which explains what you said. Tunnels got a max length of 7, and is clearly easy configurable in a session config file.

Thanks, Im going to take second look now that that is cleared up.

The client always selects the route on any onion routing network. They have to, because only they know the route. It's been a while since I played with I2P, but i'm 95% certain you can put push the circuit length up