Method to Enable/Disable Project 25 Link Layer Encryption While in Site Trunking
Original Publication Date: 2011-Sep-23
Included in the Prior Art Database: 2011-Sep-23
A Project 25 Trunking system uses Link Layer Encryption (LLE) which encrypts the control channel and voice channels with a Common Link Layer Encryption (CLEK) key. A broadcasted unencrypted Outbound Signaling Packet (OSP) indicates whether or not LLE is currently enabled or disabled at the site. Control of this indication is usually from within the infrastructure. However, when a site is in site trunking this control becomes disconnected. While in site trunking, the control of enable or disable of LLE will be performed by the subscriber securely on the control channel instead of by the infrastructure.