How works national roaming ?

[kapez]

Can someone explain to me how it works National roaming ?

...or does anyone have any white paper, document or book about this theme ?

thanks

[nbaguy]

any feedback? how successful in your case? please share your experience.

[primig]

An excellent post from Wolverine gives links to courses on
Wray Castle - GSM System Overview
Wray Castle - UMTS System Overview
here:

http://www.finetopix.com/showthread.php?4070 (http://www.finetopix.com/showthread.php?4070-More-Wray-Castle-training-courses-%28IMS-GSM-UMTS-UTRAN%29)

Have a look in there & don't forget to thank him