Bitcoin has been designed to work fine without incoming connections. A non-upgraded node can make outgoing connections to anyone. All nodes. Upgraded or not. Upgraded nodes will accept incoming connections from anyone. Upgraded or not. The only change he is suggesting, is to make sure upgraded nodes only make outgoing connections to other upgrading nodes. My own node currently has 8 outgoing and 104 incoming connections. Even if my node is upgraded, and all my outgoing connections are to segwit nodes, there is nothing whatsoever stopping non-upgraded nodes to connect to my node, and nothing is splitting the network in any way imaginable.
How does a peer to peer network work if all nodes only make outgoing connections? How does that work exactly?
That wouldn't work, of course. Another reason not to worry. Unfortunately many nodes are behind NAT and/or restrictive firewalls, and cannot accept incoming connections. Nodes which are on a public IP, and accept incoming connections, often have a hundred or more.
Logical fallacy. Dont make a statement like "Bitcoin has been designed to work fine without incoming connections" and then pretend to educate about port forwarding.
OK, I'll find a baby spoon:
Bitcoin has been designed in such a way that running a node without incoming connections work fine.
Of course you need at least one node on the network which is able to accept incoming transactions. Preferably more than one.
I can see why you dont understand the idea of how segwit nodes selectively picking connections will split the network.
I have tried ELI5. I just don't understand why you can't understand it. Please try to read again.
As I stated above, the bitcoin network depends on at least one node able to accept incoming connections. That node will accept incoming connections from all other nodes. Upgraded or not. It doesn't matter. The only way to split this, is if the single node is not upgraded. In that case all upgraded nodes will be isolated until at least one of them is able to accept incoming connections. But this isn't likely to happen, is it? Another way to split this network in the case above, would be to switch off the only node on the entire network which accept incoming connections. In that case nobody can connect to other nodes, and every node is isolated.
Fortunately in the real world there is more than one node on the network able to accept incoming connections, so this will not be a problem. If at least
one of the nodes which accept incoming transactions is upgraded, there won't be a split. Both upgraded and non-upgraded nodes will have a common connection point there. When 95% of the hashrate is on upgraded nodes already (otherwise they wouldn't be able to create upgraded blocks), we can safely assume the upgraded nodes are well connected.