The XCAP Server is a software component that runs inside a web application called Rhino Element Manager (or REM for short).

It uses OpenCloud’s Diameter Sh stack to communicate with the HSS.

Note For information on this piece of the Sentinel VoLTE product architecture, please see XCAP Support.

Example XCAP queries

XCAP Query Examples provide several examples of XCAP queries to get and modify the simservs document.

Diameter Sh configuration

The Diameter Sh stack must be configured before running the XCAP server functioning. See Configuring Diameter Sh for the XCAP server and REM.

HTTP configuration

The XCAP Server runs inside an HTTP servlet container. To configure it, please see that container’s documentation.

XCAP simservs configuration

The XCAP simservs configuration defines how an XML simservs document (typically coming from a UE) is mapped into an MMTel services document (stored in transparent data in the HSS). This mapping must be configured into the product post install. A tool is available that will populate simservs and XCAP server settings.

The rest of this section describes how to manually configure those same settings, it can be skipped if the tool is used.

This configuration is defined using XPath:


Select Sentinel ▶ XCAP — Simservs.

The resulting panel differs depending on whether a configuration has already been entered for the selected network operator.

Not yet configured

This occurs if (for example) a new network operator has been created and selected. In the following image, a network operator called TestOperator has been created and is selected.

xcap simservs mapping unconfigured operator


In this case, no network operator is selected, so the default platform configuration is displayed, for which Simservs mappings have already been configured.

xcap simservs mapping configured operator


For an existing configuration, to enter sufficient XCAP Simservs mappings for IR.92:

  • Click the + Add New button.

  • Click the + Add Mapping Group button.

A popup prompts you to enter details.

new simservs mapping group
  • Enter the following details.

Note You can enter the defaults in a selected text box by pressing the “down arrow” key (↓).
Field Name Required value for IR.92

Service indication


Service data class


Service data codec class


JXPath factory class



With the mapping group created, add mappings:

  • Click the + Add Mapping button.

A prompt displays to enter the mapping.

add mapping
  • Enter the Simservs Path and HSS Document Path.

  • Click the Save button.

Enter these defaults:

Simservs Path HSS Document Path

XCAP simservs extensions mappings

The XCAP server also supports simservs extensions mappings. This allows arbitrary elements of any transparent user data XML document from the HSS to be mapped to an element in the simservs document under the extensions parent element.


Simservs Path HSS Document Path

In these examples, select parts of operator data from the MMTel services document are being exposed to the UE for viewing and updating via XCAP as part of the Simservs document. Each can be specifically accessed via the simservs XCAP URL with the node selector specified as per the simservs path in the mapping.

Rules for creating extensions mappings

  • An extension simservs path must start with extensions/.

  • The element name after extensions/ can be any alphanumeric string. Special characters are not allowed.

  • The element name must be singular. e.g. extensions/path1 is ok, but extensions/path1/path2 is not.

  • The HSS document path has to match an actual location in the HSS data.

  • Only simple element names can be used for the HSS Document Path. i.e. no positional or attribute selectors.

Note Extensions mappings have to be created in the MMTEL-Services Mapping Group, alongside the standard MMTel mappings.

XCAP host mappings

The XCAP server may be configured to function on behalf of multiple network operators, by using host mappings. Host mappings take the ‘host’ part of an HTTP URI (in other words, XCAP query URI) and treat it as a key.

This key then identifies the:

  • Rhino cluster in REM to communicate with

  • the Sentinel network operator to use for XCAP queries.

The Sentinel network operator determines various key AVPs that are required when communicating via the diameter Sh interface.

To navigate and view XCAP host mappings:


In REM, select Sentinel ▶ XCAP.

xcap host mappings


To view a mapping in more detail, select it in the panel at left. The example shows a single host mapping, for localhost.

xcap host mappings drilldown

This configuration means that when the XCAP server receives a request, if the ‘host’ part of the HTTP request URI matches the value localhost, then:

  • The selected Rhino cluster is called Local.
    This is REM’s view of the Rhino cluster (when configuring a cluster to communicate within REM, the administratpor assigns it a name).

  • The network operator is null.
    This means Sentinel’s default network operator will be chosen.

  • The REM user account is emadm.

XCAP authentication

In the absence of an Authentication Proxy (AP), the XCAP server can be configured to authenticate requests itself using OpenCloud Sentinel AGW. Sentinel AGW provides an implementation of 3GPP GAA (Generic Authentication Architecture) procedures.

For more information, and instructions on configuring the XCAP Server with Sentinel AGW, see the Sentinel AGW Guide.


The XCAP server tries to normalize any numbers contained in CDIV rule targets and ICB/OCB conditions before accepting the request. If any number cannot be normalized, the request is rejected. Normalization is done using the Normalization Component.

Normalization can be disabled by setting the following config property, as described in the Provisioning Configuration section.



Whether to apply normalization to numbers contained in CDIV rule targets and ICB/OCB conditions.

Java type


Default value




MMTelCDIV Non-Provisionable Retarget URIs

The MMTelCDIV feature can be configured with a list of NonProvisionableRetargetURIs. As the name implies, any XCAP request containing a diversion rule with a target equal to a URI on this list, after they are both normalized, is rejected.

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Sentinel VoLTE Version 2.8.0