Yealink SIP-T2XP Administrator's Manual page 36

Administrator's Guide for SIP-T2xP IP Phones
and other control information are carried in tagged data items that are stored in the
options field of the DHCP message. The data items themselves are also called options.
DHCP can be initiated by simply connecting the IP phone with the network. IP phones
broadcast DISCOVER messages to request the network information carried in DHCP
options, and the DHCP server responds with specific values in corresponding options.
The following table lists common DHCP options supported by IP phones.
Parameter
Subnet Mask
Time Offset
Router
Time Server
Domain Name
Server
Log Server
Host Name
Domain Server
Broadcast
Address
Network Time
Protocol Servers
Vendor-Specific
Information
Vendor Class
Identifier
TFTP Server
Name
Boot file Name
20
DHCP Option
1 Specify the client's subnet mask.
Specify the offset of the client's subnet in
2 seconds from Coordinated Universal Time
(UTC).
Specify a list of IP addresses for routers on the
3
client's subnet.
Specify a list of time servers available to the
4
client.
Specify a list of domain name servers
6
available to the client.
Specify a list of MIT-LCS UDP servers available
7
to the client.
12 Specify the name of the client.
Specify the domain name that client should
15
use when resolving hostnames via DNS.
Specify the broadcast address in use on the
28
client's subnet.
Specify a list of NTP servers available to the
42
client by IP address.
43 Identify the vendor-specific information.
60 Identify the vendor type.
Identify a TFTP server when the 'sname' field in
66 the DHCP header has been used for DHCP
options.
Identify a boot file when the 'file' field in the
67 DHCP header has been used for DHCP
options.
Description