Silence Suppression - Mitel 6867i Administrator's Manual

Mitel 6800 Series SIP Phone Release 4.2.0 Administrator Guide
support SRTP and/or TLS is not enabled, the IP Phone UIs do not display the lock icon,
indicating that the call may not be secure.
Note: If you enable SRTP, then you should also enable Transport Layer Security (TLS).
This prevents capture of the key used for SRTP encryption. To enable TLS, set the
Transport Protocol parameter (located on the Global SIP Settings menu) to TLS.
You can configure SRTP on a global or per-line basis using the configuration files or the Mitel
Web UI.

SILENCE SUPPRESSION

In IP telephony, silence on a line (lack of voice) uses up bandwidth when sending voice over
a packet-switched system. Silence suppression is encoding that starts and stops the times of
silence in order to eliminate that wasted bandwidth.
Silence suppression is enabled by default on the IP phones. The phone negotiates whether or
not to use silence suppression. Disabling this feature forces the phone to ignore any negotiated
value.
You can configure silence suppression on a global-basis using the configuration files or the
Mitel Web UI.
Option to Include/Remove Silence Suppression Attribute from SDP Offer
The parameter sip remove silence suppression offer is available allowing administrators the
ability to control whether or not the silence suppression attribute should be included in the
Session Description Protocol (SDP) offer.
If enabled (1), the silence suppression attribute will be removed from the SDP offer. If disabled
(0), the attribute will not be removed from the SDP offer. This parameter is disabled by default
and requires a reboot if the value of the parameter has changed. You can configure this
parameter using the configuration files only.
CONFIGURING RTP FEATURES
Use the following procedures to configure the RTP features on the IP phone.
CONFIGURATION FILES
For specific parameters you can set for RTP features in the configuration files, see Appendix
A, the section,
"RTP, Codec, DTMF Global Settings"
IP PHONE UI
For the 6863i/6865i:
1. Press on the phone to enter the Options List.
2. Select Administrator Menu.
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