Mitel 6800 Series, Administrator'S Manual, Page: 218 / 1113

Mitel 6800 Series SIP Phone Release 4.2.0 SP2 Administrator Guide
4-65
with the first IP provided on the list. Therefore, if the IP address of the current connected flow
target was on the DNS A response list but was listed as the second or third IP address, the
phone would disconnect from the current flow target and establish a connection with the first
IP address provided on the list.
Enabling/Disabling SIP Outbound Draft 15 Support
Use the following procedure to enable/disable SIP outbound Draft 15 support.
For the specific parameter you can set in the configuration files, see Appendix A, the section,
“SIP Outbound Support”
on
page A-71
.
BACKUP OUTBOUND PROXY AND FAILOVER SUPPORT
The IP phones support a backup outbound proxy and failover. This feature provides the
following:
• The ability to specify a backup outbound proxy.
• The ability to support SIP outbound on all connection types.
• The ability to configure the SIP outbound keep alive timer.
• The ability to reestablish failed outbound connections in the background.
• The ability to support the DNS Cache Time-to-Live (TTL) requirements
Using this feature depends on the SIP network settings on your phone. The following table
identifies network configuration scenarios, and the method by which this specific feature works
in each scenario.
CONFIGURATION FILES
IF THEN
SIP OUTBOUND DISABLED AND
backup proxy and backup registrar
configured, • All invite, register, and subscribe requests attempt to use
the primary proxy/registrar first
• If the primary registrar fails, the phone registers to the
backup proxy.
• If the backup proxy fails, the phone registers using the
Address of Record (AOR) of the backup proxy, and moves
all subscriptions to the backup proxy.
• When the primary registrar comes back online, the phone
registers to it using the currently active AOR.
• When the primary proxy comes back online the phone
registers with the primary AOR to the currently active
registrar and moves all subscriptions to the primary proxy.