Support of non-secure warning tones on packet-switched networks, particularly across multiple security domains

A Multi-Level Secure (MLS) voice gateway for establishing a call between a source phone and a destination phone over a packet-switched network comprising:

• means for receiving a call attempt from the source phone to the destination phone;
• means for checking if a connection of security domains of the source phone and the destination phone via the MLS voice gateway is allowed;
• means for checking if a generation of a non-secure warning tone locally by the source phone is required;
• means for receiving an acknowledgement of a local generation of the non-secure warning tone by the source phone;
• and
• means for establishing a call from the source phone to the destination phone when the acknowledgement of the local generation of the non-secure warning tone by the source phone is received.

A non-transitory computer-readable medium including processor executable instructions, which when executed by a processor, causes the processor to:

• receive a call attempt from a source phone to a destination phone;
• check if a connection of security domains of the source phone and the destination phone via a Multi-Level Secure (MLS) voice gateway is allowed;
• check if a generation of a non-secure warning tone locally by the source phone is required;
• receive an acknowledgement of a local generation of the non-secure warning tone by the source phone;
• and
• establish a call from the source phone to the destination phone.