AASTRA 6700i series, 9143, 9480i, 9480i CT SIP Administrator Guide EN - Manual (Page 232)

41-001343-01 Rev 03, Release 3.2.2 4-69
SIP Outbound Support
The IP Phones support draft-ietf-sip-outbound-15. That specification describes how a SIP User
Agent (UA) behind a firewall, reuses an existing connection (usually the REGISTER outbound
connection) for the inbound request if the proxy supports it. The UA uses keep-alive packets to
monitor the connection status.
An Administrator can enable or disable this feature using the following parameter in the
configuration files:
•
sip outbound support
Enablling/Disabling SIP Outbound Draft 15 Support.
Use the following procedure to enable/disable SIP outbound Draft 15 support.
Note: TLS and TCP both support this feature. If the Global SIP
parameter “Persistent TLS” is set on the phone, then only one TLS
persistent connection can be established since the phone uses the local
port 5061 for connection. If the Global SIP parameter “TLS” is set on
the phone, more than one connection can be setup since the phone uses
a random local port for connection.
Configuration Files
For the specific parameter you can set in the configuration files, see Appendix A, the section, “SIP Outbound
Support” on page A-71.