Summary to avoid future forgetting.
1. Use iln to set your profile picture information. The profile picture information is represented by <msnobject>.
2 when the RC discovers a session, it will send you a p2pmsgr INVITE message.
3. After receiving the invite, SC responds to an invite acknowledge and sends a message of msnlip/1.0 200 OK.
4 RC receives SC's msnlip/1.0 200 OK and responds to a 200 OK acknowledge message.
5. When SC receives the 200 OK acknowledge message from RC, it can start to send the message of the Avatar content. First, send a data prep message that provides the sessionid and baseid content. Then, split the image file by 1202 bytes. You do not have to wait for the RC to respond to the data prep acknowledge message.
6 after RC receives the data prep, it will respond to a data prep acknowledge message. After the image content is complete, it will respond to a bye message.
7 SC answers a message whose type is 0x40 (I receive byte message ).
2 to 7 is the P2P protocol for sending profile pictures. All are performed by the SS (switchboard server) as the agent. Because my MSN is running on the Intranet, it is unclear if there is a public IP address, is there no SS thing, but according to my estimation, the Avatar sent by MSN must be sent through ss.
