How WLM works...FYI

[Philip]

Hi:

I came onto this website while surfing MSBLOG » Blog Archive » Who wants to know how Windows Live Messenger actually works? and thought it'd be nice to share it with all of you. While you're there, click on the thumbnail to see the graphical details.

Some interesting facts in a nutshell:
1) When a user starts chatting, the message is first sent to a dispatch server.
2) It is then sent to a notification server. There are 4 main ones worldwide: Singapore, Dublin (Ireland), Reading (UK), and Redmond (US).
3) Finally it is routed to a switchboard server, which transmits it to the recipient.
4) The above steps are repeated while contacts are chatting to one another.

...most of the time your message will be sent at least twice around the world, in the space of 2 seconds.

According to Live and Beyond there are "28,055,000 unique users" of WLM as of January 26, 2007. It's no wonder that sometimes WLM catches a cold or hiccups. Have a good day

[geeven]

There are some serious holes in that post.

I'm pretty sure the dispatch server is only necessary when your computer is behind a firewall (as in the picture in the post). If your computer can make a direct TCP connection to the notification server, then it does.

If the user is offline by the time the message is ready to be received, then it’ll bounce back and be saved on the switchboard session until the user logs back on again.

This is totally wrong. Offline messages aren't queued on the switchboard servers.

This is all done in the space of around 2 seconds - most of the time your message will be sent at least twice around the world, in the space of 2 seconds.

Also wrong. Sending a message sends it to the switchboard servers (which may be on the other side of the world from you). But then the switchboard sends it to your buddy who is also in the switchboard session. There aren't any extra hops.