OSCAR protocol
From Wikipedia, the free encyclopedia
OSCAR is AOL's flagship instant messaging and presence information protocol standing for Open System for CommunicAtion in Realtime. Currently OSCAR is in use for AOL's two main instant messaging systems: ICQ and AIM.
Despite its name, the specifications for the protocol are proprietary. AOL has gone to great lengths to keep competitors, namely Microsoft, Jabber, and Cerulean Studios, from implementing compatible clients for their proprietary messaging system. In 2002, AOL signed a contract with Apple, Inc., allowing them to use OSCAR (as well as AOL's own code libraries) in their iChat application. This let iChat users interact with ICQ and AIM users directly. The deal also permitted users of Apple's .Mac service to log into the AIM network using their .Mac email addresses. (This has carried over to Apple's MobileMe service.)
Large parts of the protocol are nowadays understood after reverse-engineering the protocol, implemented by an ever-increasing number of 3rd party clients.
On March 6, 2006, AOL released the AIM SDK and launched a developer website, allowing developers to build plugins for AIM Triton, and build their own custom clients, which connect over the OSCAR protocol. They had not, at that point, however, released any information about the protocol itself.
On March 5, 2008 AOL released portions of the OSCAR protocol documentation. Google also provides the ability to sign into AIM network via the Google Talk client built into Gmail.
Contents |
[edit] Packet structure
[edit] FLAP header
Every packet enclosed in a special FLAP container. It carries information about packet size, channel and its number in sequence.
| Offset (hex) | Field | Type/Size (in bytes) | Remarks |
|---|---|---|---|
| 00 | FLAP ID | byte/1 | Always contains 2A. It is mark of packet start. |
| 01 | Channel | byte/1 | |
| 02 | Number in sequence | int16/2 | Incremented by 1 each time a packet sent. Wraps to 0 after 7FFF. |
| 04 | Data size | int16/2 | Size does not include FLAP header |
[edit] See also
- Comparison of instant messaging clients
- Comparison of instant messaging protocols
- TOC protocol, AOL's free yet deprecated messaging protocol
- TOC2 protocol, the current version of the TOC protocol
[edit] External links
[edit] Protocol information
- Official OSCAR-Documentation
- OSCAR Protocol Terminology
- OSCAR (ICQ v7/v8/v9) Documentation
- UnOfficial AIM/OSCAR Protocol Specification
[edit] Implementations
| Programming language |
Implementations |
|---|---|
| C | libpurple GnomeICU |
| C# | NOscar |
| C# 2.0 | OscarLib |
| Java | joscar Instant Messenger Lib daim |
| OCaml | mlOscar |
| Python | TwistedWords |
| Perl | Net::Oscar |
