i have a idea

   i tried to add a standard SMPP interface to the bearerbox(for only know SMPP),so the bearerbox which has already connectted with the SMSC can do as a virtual SMSC.
   that means although we have only one accounts to the SMSC,the clients with a SMPP interface can connect to the SMSC via bearerbox .
   many aplications have standard SMPP interface to connect to the SMSC,but we do havent so many accounts to the SMSC,if bearerbox can do as a virtual SMSC,i think it is better than use the wireless modem as a virtual SMSC.
   but now i have meet a problem,if many SMPP clients connected with the bearerbox ,how to route the  "deliver_sm" to the proper client?
   BTW i cant understand how the bearerbox route the msg to the proper smsbox too,if more than one smsboxes connected with the bearerbox.
   in the china SMPP protocol Specification,the ton and npi of the bind_reciver is set to '0',but in the Kannel it is set to NULL, i know it will affect nothing,but ... why it is diffent?