@sztom 2020-11-30T08:48:29.000000Z 字数 1493 阅读 88

CTTP Classroom Tape Transfer Protocol - Chapter 5

CTTP LighteningZero CTTP-v1.0

Receiver

P2P Mode (Peer-to-peer Message Transfer)

Message with markword P2PSND should be recognized as sending method in P2P mode.
If the markword is P2PRST, it should be recognized as a reply method message in P2P Mode. On this kind of message, please see 5.2
When being sure that that information of TO field fits yourself, please recognize yourself as the receiver. Or otherwise you should recognize yourself as a proxy-node. (See 4.1)
Sometimes unstandard response may also has a markword of P2PSND. If you're sure FROM has communicated with you before abd it is a response through comparison, you can also recignize this message as a reply message. (See 5.2)
If you cannot response when receiving a P2P mode message in sending method, you can reply a message with empty payload and the markword RST. Example:
```
CPPT/1.0 RST
TO YYN
FROM SLC
```
When replying normally (without any error), you should ser an ERRNO field in order to indicate the reason of error.
Of course, when successful, you can set the ERRNO as 2XX (So it is better to say it is a status code than an error code). For more infomation on this situation, see 5.1.7
When replying normally, you should set the markword as P2PRST or P2PSND. It is suggested to use markword P2PRST in a reply message.
ERRNO table is shown as below: