[OpenLayers-Users] Url tile schema description

[Tomas Straupis]

Hello

  Can somebody point me to the description on how an url (tile scheme)
attribute works in OpenLayers.Layer.OSM?

  I'm in particular interested in the way an ARRAY of url's works.
That is if I specify more than one url, how will that be used?
Requests from one client will be split (how?) or first/one working
tile server will be found and used afterwards?
  What is the purpose of it? Load balancing? Failover? Something else?

  Thank you

-- 
Tomas