Protocols/MSNP/MSNC/Transports

MSNP Protocol

MSNC

Overview • MSNObject

Client Capabilities

P2P protocol

Transports • MSNSLP

Headers

P2Pv1 Binary headers

P2Pv2 Binary headers

Transfers

Display Pictures

Custom Emoticons

File Transfer

Overview

Introduction • Terms • Clients

Reference

Error List • Commands • Relying Party Suite • Spotlife

Services

XMPP • HTTP Gateway • Tabs • Activities

Documentation

Development Tools • MSNP Grid

Polygamy • URLs used by MSN

Documents

Protocol Versions

Version 21

Version 18

Version 16

Version 15

Version 14

Version 13

Version 12

Version 11

Version 9

Version 8

Version 2

MSNC

Introduction • P2P • Object Descriptor • Display Pictures • File Transfer

Scenarios

Microsoft Messenger for Mac

MSNP on WebTV (MSNTV)

Transports

The P2P protocol is designed to work independently of the "transport" - the way a message is sent. There are three known transports: switchboard, direct connection and TURN

Switchboard

Initially, P2P messages are sent over the same switchboard used by conversations, inside MSG messages with the following:

• Acknowledge type set to D
• Header Content-Type: application/x-msnmsgrp2p
• HeaderP2P-Dest set to the p2p message recipient passport address.

A sample P2P message with the message header can look like this:

MSG 1 D 143
MIME-Version: 1.0
Content-Type: application/x-msnmsgrp2p
P2P-Dest: buddy1@hotmail.com

[52 bytes binary data]

Implementation details:

• You should be able to request another switchboard if the switchboard is closed and there is a p2p conversation alive before sending a message, and continue the conversation.
• Never hardcode the MSG headers in the p2p code, it's a big design mistake and you won't be able to switch transports.

This transport allows up to 1202 bytes per chunk (with a payload size near 1343 bytes)

Direct connection

After a negotiation, based on INVITE MSNSLP messages, a direct connection may be established.

That negotiation is described in File transfer

This transport allows up to 1352 bytes per chunk.

TURN

The Traversal Using Relay NAT (TURN) transport was added in MSNP15.