SIP 101: Basics of SIP Parameters

Session Initiation Protocol (SIP) is used to initialize, synchronize, modify, and terminate data, voice, and video communication sessions over IP. Successful SIP-based VoIP and broadband service deployments depend on device provisioning software that can handle the specific requirements of SIP, including dynamic generation of configuration files, large volumes of requests for configuration files, integration with OSS systems, and the SIP user agent delivery framework.

Incognito Broadband Command Center is a device- and network-agnostic solution that supports the provisioning of SIP devices. This document outlines SIP parameter basics, including the different types of parameters used, some of their properties, and how these parameters relate to different objects in the Broadband Command Center multimedia provisioning service (MPS).

Defining SIP Parameters

A SIP device parameter takes on a value assigned by the user. You can declare parameters using SIP object definitions, which can be viewed in the ‘SIP Object Definition’ tab of a SIP phone. Every device has a unique set of object definitions that declares the parameters requiring values. Parameters can be anything from a user name and password to a domain name. There are multiple ways to define parameters, including:

  • Management Information Database (MIB)
  • XML
  • User Defined

MIB:

Parameters can be declared in a management information database (MIB) file. A SIP object definition can be based on this MIB definition. MIB-based SIP parameters are actually referenced via the SIP parameter XML configuration file, so they become available as SIP parameters.

XML:

The default phone models that are loaded into the service when it starts up are declared in the services data folder. These XML definitions can contain parameter definitions as subobjects of the phone models.

User Defined:

You can create your own parameters by navigating to the ‘SIP Object Definition’ tab of a SIP phone model, clicking the create button, and completing the form.

Types of Parameters

Per-Line Parameters:

Per-line parameters have a unique value for every phone line on a SIP device. You can define the values for these parameters either in a SIP user (which belongs to a phone line on SIP device), or SIP feature set. The per-line parameter values that you define in the SIP user will be same as the values for the phone line that relates to the SIP user (see Image 1). You can also define per-line parameter values in a SIP feature set that belong to a SIP device. To do this, you will have to specify in the SIP feature set which phone line the parameter values belong to (see Image 2). These values will then belong to the SIP user on the specified phone line.

Per-Device Parameters:

Per-device parameters have a unique value for every SIP device. These can either be defined in a  SIP device (see Image 1) or in a SIP feature set (see Image 2).  Once you attach the SIP feature set to a SIP device,  the per-device parameter values in the feature set will become the parameter values in the SIP device.

Image 1: SIP parameters without a SIP feature set. [Above] SIP per-line parameters related to phone lines. [Below]  Per-device parameters related to a SIP device.


Image 2: SIP Parameters with a SIP feature set. [Above] SIP per-line parameters related to phone lines via a SIP feature set. [Below]  Per-device parameters related to a SIP device via a SIP feature set.

 

Parameter Indices

Every SIP parameter can have indices defined by supplied values. An index can be any integer that is related to the parameter. The two most common types of indices are:

  • Phone Line Index
  • Table Index

Phone Line Index:

Per-line parameters will have a phone line index. This specifies which SIP device phone line the parameter belongs to. You will be required to set a value for a phone line index if the parameter value is defined in a SIP feature set. If the parameter value is defined in a SIP user, then you will not need to set its phone line index, because it will be set automatically when the SIP user is attached to a SIP device phone line.

Image 3: This image shows per-line parameters with a phone line index. The index of each parameter matches the phone line that it belongs to.


Table Index:

Some parameters will be grouped together in a table. A SIP device or phone line can have many instances of these tables and you will have to specify a value for a table index. This index represents which instance of the table the parameter value belongs to.  Parameters in a table can be related to values in another table.  This means that a parameter may have a table index representing the table it belongs to, as well as an index representing the table it is related to.

Image 4: Parameters grouped into tables that have more than one instance.  

The table index of the parameter is the instance of the table in which the parameters value resides.

SIP and Broadband Command Center

SIP parameters are related to some of the objects in the Broadband Command Center multimedia provisioning server (MPS), including SIP device, SIP feature set, and SIP user. SIP parameters also use various types of indices, including phone line index and table index.

Successful SIP service deployments require operators to use to right parameters, and software that best supports the specific requirements for SIP. Broadband Command Center is a service provider–grade DHCP provisioning and management solution that supports the provisioning of SIP devices across all networks.

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