Comparison of instant messaging protocols

Basic general information about the protocols: creator, version, amongst others.

Protocol	Creator	First public release date	License	Identity (not inc. alias)	Asynchronous message relaying	Transport Layer Security	Unlimited number of contacts	Bulletins to all contacts	One-to-many routing 4	spam protection	Supports groups or channels for members / nonmembers / nobody	Audio/VoIP	Webcam/Video
Gadu-Gadu	GG Network	2000 Jul 17	Proprietary	Unique number e.g. 12345678	Yes	Yes	Yes	No	Centralistic	Yes 5 (simple)	Yes	Yes	Yes
Gale	Dan Egnor	?	Open standard	Unique RSA key, aliased to user@domain	?	Yes (public/private key)	?	?	?	?	Yes (multiple simultaneous, any size, programmable, encrypted)	No	No
IRC	Jarkko Oikarinen	1988 Aug	Open standard	Nickname!Username@hostname (or "hostmask") e.g. user!~[e-mail]1	Yes, but via a memo system that differs from the main system	Yes, depending on individual server support	No3	No	Simplistic multicast	Medium	Yes (everyone, multiple simultaneous, any size)	No	No
Microsoft Messenger service Messenger|SMD|NetBEUI - Net Send	Microsoft	1990	Proprietary	NetBIOS	Yes	No	Yes	Yes	Yes	No	No	No	No
MSNP (Windows Live Messenger, etc.)	Microsoft	1999 Jul	Proprietary	E-mail address (Windows Live ID)	Yes	No	Only for certified robots	No	Centralistic	Yes	Yes	Yes	Yes
unknown protocol (Mumble)	Thorvald Natvig	1999 Jul	Open standard		Yes	Yes	Only for certified robots	No	Centralistic	Yes	Yes	Yes	Yes
OSCAR protocol (AIM, ICQ)	AOL	1997	Proprietary	Username, Email Address or UIN e.g. 12345678	Yes	Yes (Aim Pro, Aim Lite)	No	No	Centralistic	client-based	Yes (Multiple, simultaneous)	Yes	Yes
PSYC (Protocol for SYnchronous Conferencing)	PSYC Project	1995[1]	Open standard[2]	PSYC URI as in psyc://example.net/~nickname[3]	Yes[4]	Yes[5]	Yes[4]	Yes[6]	Custom multicast[7]	Yes[8]	Yes (multiple simultaneous, any size, programmable)[9]	Yes[10]	Yes[10]
RVP (Windows Messenger, etc.)	Microsoft	1997 Mar	Proprietary	Windows Active Directory Login	No	No	?	No	Centralistic	None	No	?	?
SIP/SIMPLE	IETF	2002 Dec	Open standard	user@hostname	Yes	Yes	Yes	Yes	No	Medium	?	Yes	Yes
Skype protocol	Skype	?	Proprietary	Username	No	Proprietary	?	No	?	?	Yes	Yes	Yes
TOC protocol (deprecated)	AOL	1998	Proprietary	Username or UIN e.g. 12345678	Yes	No	?	?	Centralistic	?	paying members only	?	?
TOC2 protocol	AOL	2005 Sep	Proprietary	Username or UIN e.g. 12345678	Yes	No	No	No	Centralistic	No	paying members only	?	?
XMPP (Jabber; Google Talk)	Jeremie Miller, standardized via IETF	1999 Jan	Open standard	Jabber ID (JID) e.g. usr@a.b.c/home2	Yes	Yes	Yes	Yes	Unicast lists	Several Standardized Types	Optional	Yes	Yes
YMSG (Yahoo! Messenger)	Yahoo!	?	Proprietary	Username	Yes	No	No	Yes	Centralistic	Yes	No (groups discontinued due to liability)	PMs, Conferences, and Chat Rooms	Yes
Zephyr Notification Service	MIT	1987	Open standard	Kerberos principal e.g. [e-mail]	Yes	No	Yes	Yes	Unicast lists	No	Yes	No	No
Protocol	Creator	First public release date	License	Identity (not inc. alias)	Asynchronous message relaying	Transport Layer Security	Unlimited number of contacts	Bulletins to all contacts	One-to-many routing4	spam protection	Supports groups or channels for members / nonmembers / nobody	Audio/VoIP	Webcam/Video

Note 1: In ~[e-mail], the a.b.com part is known as the "hostmask" and can either be the server being connected from or a "cloak" granted by the server administrator; a more realistic example is ~[e-mail]. The tilde generally indicates that the username provided by the IRC client on signon was not verified with the ident service.

Note 2: In usr@a.b.c/home, the home part is a "resource", which distinguishes the same user when logged in from multiple locations, possibly simultaneously; a more realistic example is [e-mail]/home

Note 3: Scalability issue: The protocol gets increasingly inefficient with the number of contacts.^[11][12]

Note 4: One-to-many/many-to-many communications primarily comprise presence information, publish/subscribe and groupchat distribution. Some technologies have the ability to distribute data by multicast, avoiding bottlenecks on the sending side caused by the number of recipients. Efficient distribution of presence is currently however a technological scalability issue for both XMPP and SIP/SIMPLE.

Note 5: There have been reports from users that the antispam filter is used to censor links to other IM programs and some websites.

See also

• Comparison of instant messaging clients
• Comparison of Internet Relay Chat clients
• Comparison of LAN messengers
• LAN messenger
• Messenger service

References

1. ^ PSYC timeline
2. ^ PSYC protocol specification
3. ^ About PSYC URIs
4. ^ ^{a b} Features of PSYC
5. ^ Features of psyced
6. ^ Friendcasting in PSYC
7. ^ Multicasting in PSYC
8. ^ SPAM strategies in PSYC
9. ^ Programmable chatrooms in psyced
10. ^ ^{a b} VoIP and webcam/video chats are implemented using PSYC over RTMP
11. ^ RFC 1324, D. Reed, 1992. 2.5.1, Size
12. ^ Functionality provided by systems for synchronous conferencing, C.v. Loesch, 1992. 1.2.1 Growth