License scheme for use with stackable devices
View Patent ↗A method ( 300 ), system ( 100 ) and apparatus ( 200 ) are provided that enable selected features in a group of two or more devices. A first of the devices ( 102 A) receives a license ( 306 ) identifying features to be enabled. The first device ( 102 A) transmits the license ( 308 ) to other devices in the group ( 102 B, 102 C). The devices in the group ( 102 A- 102 C) enable selected features ( 312 ), according to the license, from features that are available in all the devices in the group. The license may be encrypted ( 302 ) and the devices decrypt the license ( 310 ) before enabling the selected features ( 312 ). The license may be modified ( 302 ) using an identifier associated with the first device ( 102 A) of the group and the first device transmits the identifier ( 308 ) to the other devices in the group, along with the encrypted license. The devices authorize the license ( 310 ) using the transmitted identifier.
1. A method of enabling features in a stack of devices where each device in the stack at least initially has disabled features, wherein a first device in the stack also stores a first device identifier in its memory, the method comprising:
receiving a first encrypted license file by the first device in the stack wherein the license file comprises the first device identifier;
decrypting the first encrypted license file by the first device using the first device identifier from its memory;
enabling features in the first device by the first device using the decrypted license file;
determining by the first device that a second device is in the stack, encrypting by the first device the license file using the first device identifier and transmitting by the first device the first device identifier and the encrypted license file to the second device;
decrypting the encrypted license file by the second device using the transmitted first device identifier, authorizing by the second device the decrypted license file by determining that the transmitted first device identifier is in the decrypted license file and enabling features in the second device using the decrypted license file.
2. The method as in claim 1 , further comprising:
at the first device:
receiving a message transmitted to an intended recipient device in the stack; and
transmitting the message from the first device to the intended recipient in the stack.
3. The method as in claim 1 further comprising:
in a device designated as a non-base unit in the stack:
storing a unique key in volatile memory;
storing the license file in non-volatile memory; and
subsequent to removal of power to the non-base unit, re-establishing communication with the first device in the stack to retrieve the unique key.
4. The method as in claim 1 ,
wherein the devices in the stack enable selected features according to the license file based on use of the license by each of the devices in the stack; and
wherein features enabled by the devices in the stack are features that are available to all of the devices in the stack.
5. The method as in claim 1 , wherein each of multiple features identified in the license file are supported by all of the devices in the stack.
6. The method as in claim 1 , wherein the stack of devices includes a third device; and
wherein the first device is a base unit that communicates with other devices in the stack, the method further comprising:
receiving a network message at the first device;
transmitting the network message from the first device on a communication link through the second device to the third device in the stack.
7. The method as in claim 1 , wherein each of the devices in the stack supports a set of identical features; and
wherein the license file specifies which features in each of the devices to enable based on loading of the license file into the devices in the stack.
8. The method as in claim 7 , wherein resetting of the stack of devices, during which the first device fails, renders the second device in the stack unable to use the license file to enable features.