TLS extenstion pre_sharek_key

Question

任何人都可以向我解释什么是 pre_shared_key TLS 扩展以及它与 Session Ticket TLS 扩展有什么关系，因为我观察到当 TLS Client Hello 消息中存在 pre_shared_key 扩展时，Session Ticket 扩展不存在

Answer 1

... when the pre_shared_key extension is present in the TLS Client Hello message the Session Ticket extension is absent

The first one is session resumption with TLS 1.3, the second with TLS 1.2 and lower. There are several information about this protocol change on the internet, like TLS Session Resumption TLS 1.3 uses 0-RTT Handshakes .