The "p2p" capability is present on all connections. After the initial handshake, both sides of the connection must send a Hello message. Upon receiving the Hello message a session is active and any other message may be sent. Implementations must ignore any difference in protocol version for forward-compatibility reasons. When communicating with a peer of lower version, implementations should try to mimic that version.
At any time, a Disconnect message may be sent.
In practice, a maxed-out geth node will send a Disconnect msg before the Hello, which kind of makes more sense than sending a Hello just to follow it with a Disconnect, but then the spec should probably be updated to reflect that after the initial handshake either a Hello or a Disconnect can be sent
fjl
commented
4 years ago
In practice, a maxed-out geth node will send a
Disconnectmsg before the Hello, which kind of makes more sense than sending aHellojust to follow it with aDisconnect, but then the spec should probably be updated to reflect that after the initial handshake either aHelloor aDisconnectcan be sent