Basic Phone Configuration, Elements and Relationship

Basic endpoint configuration for IP Phones are are as follows:

• Phone NTP Reference (SIP)
• Date/Time Group
• Presence Group
  
• Device Pool (Cisco Unified CM Group, Regions and Locations)
• Common Device Configuration
  
• Security Profile
• Softkey Templates
• Phone Button Templates

Phone NTP Reference
The Phone NTP Reference is configured to ensure that SIP (Session Initiation Protocol) phones get their date and time from the NTP server from the NTP server. If the NTP server is not reachable the SIP phone uses the 200 OK response date header from the REGISTER message for the date and time. SCCP phones get their date and time information from the SCCP messages.

Date/Time Group
Devices connected to CUCM can be configured with different time zones, these time zones are configured in the Date/Time Group which then get applied to a Device Pool. One Date/Time Group can be assigned to one Device Pool and that Device Pool is assigned to one device. By default a CMLocal Date/Time Group is configured automatically at time of installation, this group is part of the system and should not be renamed.

Regions
Maximum bandwidth for audio and video calls are specified using Regions. The audio codec determines the type of compression and the maximum amount of bandwidth that is used per audio call and the video call bandwidth comprises the sum of the audio bandwidth and video bandwidth but does not include overhead. Note: The G.711 audio codec is used by default.

Locations
The implementation of call admission control (CAC) is used to regulate audio and video availability by limiting the amount of bandwidth available for audio and video calls for a location.

Device Pool
Device and location information and other device characteristics are defined using Device Pools, these are common hardware setting that are assigned to IP Phones.

Common Device Configuration
Common Device Configuration is similar to Device Pools but they are user related, such settings are Softkey Templates, Music On Hold and Locales.

Cisco Unified CM Group
CUCM Groups are used for redundancy and call process load balancing using a prioritized list of CUCM primary, secondary and tertiary (backup) servers. When a device attempts to register to the primary server that maybe unavailable the device tries to register to the next secondary backup servers, if this secondary server is also unavailable the device tries the tertiary server (three CUCM servers can be listed).

Security Profile
All devices need to be assigned a security profile. Security profiles included settings like device security mode, Certificate Authority Proxy Function (CAPF) settings, digest authentication settings (SIP only) and encrypted configuration file settings. Default none-secure profiles are configured during the installation on CUCM.

Softkey Templates
Allows CUCM administrators to configure softkey templates options according to the devices intended roles and or applications.

Phone Button Templates
Allow for the configuration of common button templates types such as Speed Dials, Lines, Privacy, Service URL, Speed Dial BLF and Call Park BLF.


Elements Involved in Configuring an IP Phone
Note: Some of these elements can applied to multiple locations, such as the 'Locations', they can be applied at the Device Pool as well as the phone configuration. In this case the phone configuration would have priority over the Device Pool configuration.