OpenBTS provides an open source alternative to legacy telco protocols and 
traditionally complex, proprietary hardware systems.

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
You can contact the copyright owner at <harvind@rangenetworks.com>.
 
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ADDITIONAL TERMS TO THE AGPLv3 LICENSE FOR OPENBTS

Permissive Terms Supplementing the License
               
1. Remote Interaction Through IP Networks.      
 
Remote interactions through interfaces is generally a "remote network 
interaction" and requires compliance with Section 13 of the AGPLv3. 
However, remote interactions other than the GSM air interface are permitted
without requiring compliance with Section 13 of the AGPLv3.  This exemption 
of interactions with interfaces other than the GSM air interface from the 
requirements of Section 13 is an additional permission granted to you. 
 
2.  GSM "A5" cipher stream generation libraries
 
Notwithstanding any other provision of this License, you have permission to 
link the Program with GSM "A5" cipher-stream generation libraries provided 
under any license that allows redistribution of those libraries in binary 
form, provided that the function of any such library is limited to the 
generation of cipher-stream bits. This permission to link to certain 
libraries is an additional permission granted to you. 

Other Terms Supplementing The License under Section 7 of the APLv3
 
"OpenBTS" is a trademark of Range Networks, Inc., registered with the US 
Patent and Trademark Office.  Your use of OpenBTS software does not include 
the right to use the OpenBTS trademark.

END OF ADDITIONAL TERMS
 
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RECOMMENDATIONS

How to comply with Section 13 of the AGPLv3 license.

OpenBTS includes an implementation of the GSM network cellular air interface, 
as well as other interfaces to IP networks.  Range Networks believes that 
interaction of cellular handsets with the OpenBTS software is considered 
"remote network interaction" for the purposes of the AGPLv3 and cellular 
users have the right to obtain source code as provided in Section 13 of 
AGPLv3 except for the additional permissions granted above.
 
The recommended method for compliance with Section 13 of the AGPLv3 license 
for OpenBTS is to deliver a text message to each handset that attaches to the 
OpenBTS cellular network.  At a minimum, that text message should include the 
string "OpenBTS AGPLv3" and a URL that can be used to access the OpenBTS 
source code.  This message need not be delivered to handsets that are denied 
registration with the network, since those handsets have been denied service.
 
In OpenBTS 2.6 and above, such text messages can be delivered with the 
"Welcome Message" feature. See OpenBTS documentation for more information 
on the use of this feature for AGPLv3 compliance.

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