Luckily the topic of Data/GPRS/3G connections are well covered at susewiki.org. This page works with any Linux distro [that I have tried so far] since it uses kppp to handle your connection.
http://susewiki.org/index.php?title=Using_GPRS_Internet
Notice: This is for a 3G connection using your mobile phone, and not other ways of 3G (usb/pcmcia/pci datacard).
Quick Reference
- Customize pppd arguments and add the following arguments:
- * lcp-echo-failure 10000
- * lcp-echo-interval 30000
- * lcp-max-configure 0
- * lcp-max-failure 10000
- * lcp-max-terminate 0
- * lcp-restart 30000
(even 0 may work)
(even 0 may work)

