surely two CPU；2GB RAM， the HDD cache size ,I don' t know so...

any one can solve this problem...

Wireless ADSL Modem(Bridge) ----> Mikrotik WAN (use AR5414A for pppoe-out).OK...?

Add Credit to the specific User with Time Limit, It will be Disabled automatically as the time limit is over.

Ye...I am used it.

I think,it is unsettled wireless to link,so user IP better than PPPOE.

Read about VPN material, PPTP、IPSec、MPLS, majority of Enterprise Use ing it。

http://blog.chinaunix.net/u/32500/showart_282217.html

"200km Distance of the sea surface ", How you are to build up The Wireless Relay Station?
use Height Balloon or Ship ?