CTTP Classroom Tape Transfer Protocol - Chapter 5

Tags： CTTP LighteningZero CTTP-v1.0

Receiver

P2P Mode (Peer-to-peer Message Transfer)

Message with the markword P2PSND should be recognized as sending in the method of 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 (5.ii).
When being sure that that information of the TO field fits yourself, please recognize yourself as the receiver. Or otherwise, you should recognize yourself as a proxy-node. (See 4.1 (4.i)).
Sometimes off standard response may also have a markword of P2PSND. If you’re sure FROM has communicated with you before and it is a response through comparison, you can also recognize this message as a reply message (See 5.2 (5.ii)).
If you cannot respond when receiving a P2P mode message in the sending method, you can send a message back with an empty payload and the markword RST. e.g:
```
 CTTP/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 for the 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 information on this situation, see 5.1.7 (5.i.g).
When replying normally, you should set the markword as P2PRST or P2PSND. It is suggested to use the markword P2PRST in a reply message.

ERRNO table is shown as below:

CTTP