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Cisco IP Phone Models 7905G and 7912G Administrator Guide (SIP)
OL-4277-01
Chapter 3 Configuring the Cisco IP Phone Models 7905G and 7912G for SIP
Default Boot Load Behavior
network connectivity. However, if your network does not use a DHCP server, you
must manually configure the IP address of the phone, the subnet mask used by the
phone, and the network gateway (default router) IP address for the phone.
All Cisco IP Phones are shipped with a bootload image. However, because this
image is not a fully-functional signaling image, the image must be upgraded. The
image is designed to be automatically upgraded by a properly configured TFTP
server. To configure the Cisco IP Phone to automatically upgrade to the latest
signaling image, see the “Upgradecode Parameter Detail” section on page 8-41.
In addition, the Cisco IP Phone obtains its configuration file during the bootload
process.
Here is a summary of the default Cisco IP Phone behavior during its boot-up
process:
1. The Cisco IP Phone uses the Cisco Discovery Protocol (CDP) to discover
which VLAN to enter. If the phone receives a VLAN ID response from the
network switch, the phone enters that VLAN and adds 802.1Q VLAN tags to
its IP packets. If the phone does not receive a response with a VLAN ID from
the network switch, the phone assumes it is not operating in a VLAN
environment and does not perform VLAN tagging on its packets.
Note If your network environment is not set up to handle this default behavior,
make the necessary configuration changes by referring to the “Specifying
a Preconfigured VLAN ID or Disabling VLAN IP Encapsulation” section
on page 3-4.
2. The phone contacts the DHCP server to request its own IP address.
Note If your network does not use a DHCP server, you must manually
configure the IP address of the phone, the subnet mask used by the phone,
and the network gateway (default router) IP address for the phone. For
more information, see the “Minimum Configuration Settings for the
Cisco IP Phone Models 7905G and 7912G” section on page 3-9.
3. The phone also requests the IP address of the TFTP server from the DHCP
server.