No connection between nodes on same LAN

[Daniel Schall]

Hi Michael,

On Tue May 25 20:13:51 CEST 2010, Michael Braun wrote:
> > 2) On success, they
> > will drop the direct connection to the public endpoint of the host they
just
> > connected to and will use the local endpoint instead for forwarding data
> > packets.

> Imagine  C -- A -- B with A is the public endpoint and B, C are
> in the same subnet. Now let C, B discover that they are in the same
> subnet. Then they will partition the network into  B -- C, A where
> B,C cannot reach A and vica versa.

The "public endpoint" refers to the local UDP-endpoint of each node, for
example a node which has two physical LANs connected with IP addresses
192.168.0.10 and 10.0.0.12 and also has a NATed connection to the outside
world, would have three UDP endpoints:
192.168.0.10:655,
10.0.0.12:655 and
pu.bl.ic.ip:1337 (an endpoint on the NAT router)

Regarding your example this would mean for the three nodes
C -- A -- B, with B and C on the same LAN, that after a short while, the
connections between B and C should be established directly.

Let's make an example and annotate UDP endpoints for the nodes:
A:
	1.1.1.1:123	(public)
B:
	192.168.0.1:123 (LAN)
	2.2.2.2:1123 (public, NATed)
C:
	192.168.0.2:123 (LAN)
	2.2.2.2:2123 (public, NATed)

First, the situation would look like this:
C (2.2.2.2:2123) -- (1.1.1.1:123) A (1.1.1.1:123) -- (2.2.2.2:1123) B

After C and B have detected, they are on the same LAN, they will directly
connect:
C (2.2.2.2:2123) -- (1.1.1.1:123) A (1.1.1.1:123) -- (2.2.2.2:1123) B
++++
C (192.168.0.2:123) -- (192.168.0.1:123) B

The connection to A is not affected by this.


Best,

Daniel