Aastra SIP 53I Administrator's Manual page 575

Configuration Parameters
Operational, Basic, and Advanced Parameters
Parameter –
sips persistent tls
Description
Format
Default Value
Range
Example
41-001160-00, Release 2.1, Rev 04
Configuration Files
Enables or disables the use of Persistent Transport Layer Security (TLS).
Persistent TLS sets up the connection to the server once and re-uses that
connection for all calls from the phone. The setup connection for
Persistent TLS is established during the registration of the phone. If the
phones are set to use Persistent TLS, and a call is made from the phone,
this call and all subsequent calls use the same authenticated connection.
This significantly reduces the delay time when placing a call.
Notes:
1. Persistent TLS requires the outbound proxy server and outbound
proxy port parameters be configured in either the configuration files or the
Aastra Web UI (Advanced Settings->Global SIP->Basic SIP Network
Settings). There can be only one persistent TLS connection created per
phone. The phone establishes the TLS connection to the configured
outbound proxy.
2. If you configure the phone to use Persistent TLS, you must also
specify the Trusted Certificate file to use. The Root and Intermediate
Certificates, Local Certificate, and Private Key files are optional.
Boolean
0 (disabled)
0 (disabled)
1 (enabled)
sips persistent tls: 1
aastra.cfg, <mac>.cfg
A-73