Parameter Sources And Their Precedence - Avaya 4602 Administrator's Manual

Introduction to Managing the 4602 SIP Telephone
!
CAUTION:
SIP uses a specific order to establish the parameters any telephone ultimately
CAUTION:
uses. Since data can be derived from many sources, be sure to understand
which action or method of assigning/updating parameters takes precedence over
another. See the next section,
information. Most importantly, be aware that a system or telephone restart always
sets all parameters back to their default values.

Parameter Sources and Their Precedence

The following steps show the order in which telephone settings get assigned or updated. It is
important to understand how these data sources interact to create the active configuration that
the phone finally uses.
1. The first time, and only the first time a phone starts up, default values are copied to NVRAM.
These default values are specified in
2. Next, the telephone copies the NVRAM values for all parameters into the active
configuration.
3. The phone then runs DHCP, if it is enabled, to obtain an IP Address, Subnet Mask,
Gateway(s), DNS Server Address, and Configuration HTTP Server IP Address. These
values overwrite the current values in the active configuration.
4. The phone then downloads a configuration file and uses the values in this file to overwrite
the current values in the active configuration, unless the OverrideWeb parameter is
disabled (see
To summarize the result of these four steps:
Configuration file parameters have precedence over DHCP parameters.
DHCP parameters have precedence over manually-configured parameters set using the
Web interface or the telephone dialpad Setup command.
Note:
Using the Setup command (from either the Web interface or dialpad) before
Note:
DHCP completes causes the saved setup values to overwrite the current values
in NVRAM.
This precedence is important to understand if you plan to use a combination of parameter
sources. It is also important to note that the dialpad Setup command and the Web interface
both display data from the currently active configuration and not NVRAM. However, when
values entered using either the Web interface or dialpad are saved, the displayed values
overwrite the value in NVRAM.
Thus, in the configuration process, saving a value from the Web interface or the Setup
command takes effect only after the phone reboots and re-reads the values. Even then, DHCP
or configuration files always have precedence over manually entered or Web interface values.
16 4602 SIP Telephone SIP Release 1.2 Administrator's Guide
Appendix A: Configuration
Parameter Sources and Their Precedence
Appendix A: Configuration
Parameters).
for
Parameters.