AASTRA 6700i series, 9143, 9480i, 9480i CT SIP Administrator Guide EN - Manual (Page 637)

6-10 41-001343-01 Rev 03, Release 3.2.2
Auto-discovery Using mDNS
The IP phones can perform an auto-discovery of all servers on a network using mDNS. When
the IP phone discovers a TFTP server, it is automatically configured by that TFTP server.
An unconfigured phone (phone right out of the box) added to a network, attempts to
auto-discover a configuration server on the network without any end-user intervention. When it
receives DHCP option 66 (TFTP server), it automatically gets configured by the TFTP server.
An already configured phone (either previously configured by auto-discovery or manually
configured) added to a network, uses its predefined configuration to boot up.
Notes:
1. Configuration parameters received via DHCP do not constitute
configuration information, with the exception of a TFTP server.
Therefore, you can plug a phone into a DHCP environment, still use the
auto-discovery process, and still allow the use of the TFTP server
parameter to set the configuration server.
2. DHCP option 66 (TFTP server details) overrides the mDNS phase of
the auto-discovery. Therefore, the DHCP option takes priority and the
remaining process of auto-discovery continues.
3. As the phone performs auto-discovery, all servers in the network
(including the TFTP server), display in the phone window. However, only
the server configured for TFTP automatically configures the phone.