[Asterisk-Users] HINTING, how it works... Please explain

[Asterisk]

Hi,

I was wondering if the Dev community could help me out with a few 
answers to questions I am having a hard time getting info on.

Firstly, is there a document describing HINTING and how it works so I 
can program a tool to monitor it?

Also, I have noticed with my Grandstream phone.  They register with the 
Asterisk Box, but if the Asterisk Box is restarted, it looses track of 
the registered phones wanting to know about the call process...
How is hinting suppose to deal/recover from this.  Are the grandstream 
phone suppose to re-register every 15min or some configurable value, as 
to recover from this?

Thanks,
James