Cisco IP Phone Boot Process

1. Cisco Switch detects PoE capabilities
2. Switch sends voice VLAN via CDP
3. IP Phone receives a DHCP request, including option 150
4. IP phone contacts the TFTP server, receives the configuration file
5. IP phone registers with the CME router

The DHCP and TFTP servers can be running on the CME router.

TFTP Device Configuration File

IP phones download their specific configuration file (XML) from the TFTP server.

SEPMACADDRESS.cnf.xml

If not found, XMLDefault.cnf.xml is used to stage phones.

The configuration file points to CUCM or CUCME

Auto Registration

1. Phone attempts normal boot process
2. Phone downloads XMLDefault.cnf.xml
3. Updates firmware if required
4. CUCM creates device-specific XML
5. phone reboots and uses device-specific file to complete registration

SIP Phone Registration

1. Phone requests CTL file if present
2. Phone requests SEPMACADDRESS.cnf.xml if present, else XMLDefault.cnf.xml
3. SIP phone requests load files
4. Downloads the local dial plan if configured