Supplemental Guide – DOC. 8412A
UC-P100-S/UC-P110-S Phones for Skype for Business
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Parameter
DHCP Option
Description
Vendor Class
Identifier
60
Identify the vendor type.
TFTP Server Name 66
Identify a TFTP server when the 'sname' field in the DHCP
header has been used for DHCP options.
Boot file Name
67
Identify a boot file when the 'file' field in theDHCP header has
been used for DHCP options.
Skype for Business
Server
120
Specify a list of Skype for Business Servers available to the
client.
For more information on DHCP options, refer to the Internet Engineering Task Force
(IETF) specifications for RFC 2131 or RFC 2132 at ietf.org.
If DHCP options for automatically discovering the provisioning server address on the
DHCP server cannot be configured, an alternate method is required. Connecting to the
secondary DHCP server that responds to DHCP INFORM queries with a requested
provisioning server address is one possibility. For more information, refer to the IETF
specifications for RFC 3925. If a single alternate DHCP server responds, this is
functionally equivalent to having the primary DHCP server respond with a valid
provisioning server address. If no DHCP servers respond, the INFORM query process will
retry and eventually time out.
DHCP Option 66 and Option 43
Skype for Business phones support obtaining the provisioning server address by
detecting DHCP options during startup.
The phone will automatically detect option 66 for obtaining the provisioning server
address. DHCP option 66 is used to identify the TFTP server. DHCP option 43 is a vendor-
specific option, which is used to transfer the vendor-specific information.
The administrator can use vendor class identifier, specified by DHCP option 60, to send
the phone a customized configuration in option 43. Depending on the vendor class ID it is
configured for, the option 43 might have different values. Two vendor class identifiers
are used when deploying with the Skype for Business Server: a VLAN ID request (vendor
class ID: CPE- OCPHONE) and a certificate provisioning service URL request (vendor
class ID: MS-UC-Client). For more information on DHCP option 60, refer to “DHCP
Option 60” on page 21.
To use DHCP option 66 and option 43, make sure the DHCP Active feature is enabled.
