Bandwith meter

["Dror Mor" <tow () corky net>]

Hello all,
    I have a wireless CDPD modem that is connected to one of my Linux machines via serial. I need to check the bandwith 
of this modem for a long period of time (1-3 days), but I need a program for it. anybody knows of such a program?

                                                    Thanks alot 
                                                       Dror Mor