Negotiating Device Security Mode

The actual security mode used for a call depends on the configuration of both IP Phones participating in the call. As shown in Figure 27-9, these rules apply:

• If either device in a conversation is set to Non Secure, a nonsecure call (that is, a call without authentication and without encryption) is placed.
• If both devices are set to Encrypted, an encrypted call (that is, a call with authentication and encryption) is placed.
• If one device is set to authenticated and the other phone is set to either authenticated or encrypted, the resulting call will be authenticated.

Figure 27-9. Device Security Negotiation