[JDEV] MSN vs Jabber

[David Waite]

Mattias Campe wrote:

> I know that ICQ only has a part that is completely open (the AIM TOC 
> protocol), but what about MSN? Does MSN have a completely open 
> protocol? Do you have to pay some money to use it, like if you would 
> like to build your own client? Can you install a server for free? 

AIM/ICQ do not have an open protocol - AOL has stated they will not 
guarantee access to any party which uses TOC without a financial 
agreement with them (and have actively blocked parties using both TOC 
and their main OSCAR protocol)

Microsoft at one time submitted the MSN protocol to the IETF as an 
informational draft. They did not seek to make this an informational 
RFC, and let this draft expire (making it slightly harder to find 
nowdays). Their newer protocols are not documented.

MSN, AIM, ICQ, and Yahoo have all taken active steps to prevent third 
parties without formal business relationships from iterfacing with their 
networks, under _any_ protocol.

> In general, what are the differences between Jabber and MSN? What are 
> the "equalties"? What are the advantages to use Jabber and what are 
> the disadvantages? 

Jabber is decentralized, while MSN uses a central server (your 'address' 
on the MSN server resembles an email address, but all accounts are 
handled by their server farm). Jabber is open - you can write your own 
server and clients, as well as use and contribute to several open-source 
servers and clients already available.

Jabber is extensible through XML, while MSN is only extensible through 
new MIME types. I don't believe you can register type handlers with the 
official MSN clients, making that extensibility limited to people using 
the same third-party client - and there is no feature negotiation.

The MSN protocol was built around Microsoft's need for the ability to 
massively farm their servers, which gives it some interesting 
properties. Jabber is designed for decentralized access across domains, 
but wasn't designed with farming and data locality within one domain in 
mind. However, MSN has some deficiencies in their farming as well  - for 
example, the switchboard servers are a decently good idea, but horrible 
when it comes down to their protocol and implementation.

MSN's big advantage is (of course) user-base. Microsoft built up a user 
base in a way that only someone with a monopoly on computer operating 
systems could ;-) However, I've seen numbers in the past that indicate 
their userbase has significantly lower usage by percentage than the 
other three main portal IM systems; I figure this is because people set 
up an MSN account when they set up their computer not knowing what it 
is, or wanting to use it. The client then just logs in and stays silent 
in their tooltray whenever they connect to the internet.

-David Waite