Actually should be Jabber scalability, was Re: [JDEV] newbie questions

mark at mark at
Thu Oct 26 16:48:30 CDT 2000

I was hoping someone a bit more qualified (in particular on the 2.1 
stuff) than I would handle this, but I think they felt they're time was 
better spent answering other questions.

I'll answer inline.
On 24 Oct 00, at 15:28, Basim Baassiri wrote:

> Hi,
> I have a few questions to ask, I couldn't find these answers on, 
> or  if the answers to my questions are at the 
> places could you let me know.  Other than that the Jabber project is an 
> excellent idea.
> so here they are:
> Can Jabber handle 100 millions users?
1.0 cannot. 1.2 has a better shot, later version even better, in 
particular after we get the multiplexer working. 

That being said, none of the other current IM offerings can either. 
The largest IM subscriber base is AOL and it has what 7 million? 
There's not even an email system with that many users and e-mail 
is much more popular than IM at the moment.

In jabber 1.0 (the current release) you can scale to several 
thousand on a single server. In 1.2 you'll be able to get that into the 
tens of thousands, perhaps even the hundreds of thousands with 
the right combination of XDB backends (this where user information 
is managed on the server) and enough boxes (Jabber 1.2 will be 
able to support server farms).

There's only a few services in the world that would require such 
scalability. That would be the major ISPs and telephone 
companies. Most of us won't ever see more than a few thousand. 
And I imagine that the infrastructure will follow email. Every 
organization that's much larger than a 100 people will have several 
IM servers scattered about, behind a common gateway. That's not 
to imply that Jabber can't be centrally managed, just that Internet 
technology is decentralized by nature. 

> How many concurrent connections can Jabber handle?

I'd say several thousand in the 1.2 architecture (BTW 1.2 is now in 
release candidtate stage, with final release expected early next 
month, November 2000). Not sure in the current release.
> What if the proprietary instant messaging systems change their protocol how 
> long will it take for Jabber project to make the transition?
I don't think it's likely that any of the major providers will change 
their protocols now. There's too many clients deployed & many of 
those clients are native clients, not Java applets. If they change the 
protocol, they have to change their clients. Plus most of the 
providers realize that IM is like email there's more $$ to be made 
by having the service and not forcing users to just their own 

Also most of the providers (minus AOL) are working on developing 
a common protocol and there is also work in the IETF to 
standardize an IM protocol.

However, if for some reason, they were to change their protocols, 
the time to migrate would depend upon on several factors, such as 
if the protocol specification was published (otherwise you have to 
hack the protocol via a packet sniffer), the amount of changes in 
the protocol and the availability of people to write the new transport. 
If it's a common service like AIM, MSN or Yahoo, I imagine it would 
be within a week or two (no more than a month). 

> Your conscience may not keep you from doing wrong, but it sure keeps you from 
> enjoying it. 
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Mark Wilcox
mark at

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