Mitel 6800i Series Administrator's Manual page 157

#The 6769i phones do not contact the RCS.
class "vendor-class-69i" {
match if option vendor-class-identifier="AastraIPPhone6869i";
vendor-option-space AastraIPPhone;
option AastraIPPhone.contact-rcs false;
USING OPTION 120 ON THE IP PHONE
DHCP Option 120 (as referenced in RFC 3361) allows SIP clients to locate a local SIP server
(i.e. outbound proxy server) that can be used for all outbound SIP requests. Using the "use
dhcp option 120" configuration parameter, administrators can enable support for DHCP Option
120 on the IP phones. This is particularly useful when service providers require the IP phones
to use certain outbound proxy servers or Session Border Controllers (SBCs) based on
geographical location and have provisioned the outbound proxy by using DHCP Option 120.
The parameter is disabled by default.
Considerations
The following considerations must be taken into account when enabling support for DHCP
Option 120 on the IP phones:
• If the parameter is enabled and DHCP Option 120 contains a valid value, the IP phones
will use the server IP/name obtained via DHCP Option 120 as the outbound proxy for both
the Global SIP and Line 1 profiles.
• If Line 2 is configured and the outbound proxy is not defined, the phone will use the outbound
proxy located in the Global SIP profile.
• If Line 2 is configured with a valid outbound proxy, the phone will retain the configured Line
2 outbound proxy and ignore the Global SIP profile. This allows for Line 2 to be registered
to another service with another outbound proxy if required.
• If Line 2 is configured for another service but no outbound proxy is wanted/required, ad-
ministrators should not leave the outbound proxy as undefined (i.e. 0.0.0.0) as the phone
will use the outbound proxy located in the Global SIP profile. Instead, administrators should
specify the proxy/registrar's address as the outbound proxy.
• If the parameter is enabled, but the server does not have an outbound proxy configured,
DHCP Option 120 is ignored and the phone will behave as if the parameter is disabled.
• As Option 120 does not support port numbers directly, if a non-standard port (i.e. other than
5060) is required, this must be set using the configuration parameter "sip outbound proxy
port" or by the use of DNS SRV in which case "sip outbound proxy port" must be set to 0.
Enabling/Disabling DHCP Option 120 Using the Configuration Files
Use the following procedure to enable/disable DHCP Option 120 using the configuration files.
CONFIGURATION FILES
For specific parameters you can set in the configuration files, see Appendix A, the section,
on
"DHCP Option Settings"
.
page A-12
Network Settings
4-10