Contents
| 1 | Introduction |
| 1.1 | Prerequisites |
2 | Overview |
| 2.1 | Subfunctions |
3 | Dialog Event Notifier Service Configurations |
| 3.1 | DEN Administrative State Configuration |
4 | Performance Management |
5 | Fault Management |
1 Introduction
This document describes how to configure the Dialog Event Notifier (DEN) service in the MTAS.
1.1 Prerequisites
It is assumed that the user of this document is familiar with the Operation and Maintenance (O&M) area, in general.
1.1.1 Licenses
The Dialog Event Notifier service does not have a license. To enable the DEN service, no specific license must be installed. Instead, the activation of the service is initiated with the mtasDenAdministrativeState Configuration Management (CM) attribute which is to be set to TRUE in the MtasDen Managed Object Class (MOC).
1.1.2 Documents
Before starting any procedure in this document, ensure that the following documents are available:
1.1.3 Conditions
Before starting any procedure in this document, ensure that the following condition is met:
- An Ericsson Command-Line Interface (ECLI) session in Exec mode is in progress.
2 Overview
The Multimedia Telephony (MMTel) Application Server (AS) allows out-of dialog subscription to Dialog Events as defined in RFC 4235. Each device sends an explicit SUBSCRIBE request to the number of the subscriber. The MMTel AS maintains separate subscriptions for each device. Devices refresh the subscription periodically.
2.1 Subfunctions
The subfunctions of the DEN service are included in this section.
2.1.1 Subscription
The DEN service supports out-of-dialog subscription by receiving an explicit SUBSCRIBE request from the client. Upon successfully accepting a subscription, MMTel AS starts the expiration timer and sends a NOTIFY request immediately to communicate the current dialog state to the subscriber.
2.1.2 Un-subscription
The DEN service considers the SUBSCRIBE message from an active subscriber containing Expires set to 0 as un-subscription. Receiving such SUBSCRIBE request, MMTel AS stops the expiration timer and sends a 200 OK response with inserting Expires header value of 0.
The successful un-subscription triggers a final NOTIFY message. This request contains Subscription-State header with a value of "terminated" and a "reason" parameter with a value of "time-out".
2.1.3 Refreshing the Subscription
The subscriber device can refresh its subscription by sending a re-SUBSCRIBE request with non-zero Expires header. With a successful re-SUBSCRIBE request, the DEN service extends the subscription expiration time with the value of the Expires header and MMTel AS sends 200 OK response inserting the Expires header.
The refreshing SUBSCRIBE request triggers a new immediate NOTIFY message where the Subscription-State is set to "active" and the XML document is empty.
2.1.4 Polling the Subscription
The DEN service accepts the out-of-dialog SUBSCRIBE request with an Expires header containing zero coming from a subscriber without persistence subscription. Upon receiving of this SUBSCRIBE request, DEN sends a NOTIFY request containing the dialog states on the other devices of the served user. The NOTIFY message contains a Subscription-State header with a value of "terminated", and a reason parameter with a value of "time-out", but the XML document is empty.
Although the polling and unsubscribing SUBSCRIBE both contains Expires header with zero value, the significant difference between the requests is that polling SUBSCRIBE does not include tag parameter in the To header field.
2.1.5 Subscription Expiry
If no refreshing SUBSCRIBE is received before its expiration time, the subscription is removed. When removing the subscription, MMTel AS sends a terminating NOTIFY request for expired subscription and removes subscription at the end of the NOTIFY transaction. The NOTIFY request includes Subscription-state value of "terminated" to inform the device that the subscription is being removed. If such a request is sent, the Subscription-state header field contains a "reason=time-out" parameter.
2.1.6 Notification about the Dialog State Transition
When more devices of a served user subscribed to dialog notification events, and changes of the dialog state of a particular device occur (call establishment and termination, change in media type or direction), the other devices get notification about the changes in the XML document included in a NOTIFY request.
2.1.7 Shared Appearances Element in Call Notifications
The DEN service can include shared appearances, that is, <exclusive> element in an XML document of notification messages as described in RFC 7463 if it is configured. Setting the <exclusive> element to value TRUE of a specific call dialog indicates restrictions in call handling operations of the dialog, for example call pull.
3 Dialog Event Notifier Service Configurations
The DEN service is controlled by the MtasDen MO.
3.1 DEN Administrative State Configuration
The DEN service is enabled by setting the mtasDenAdministrativeState attribute in the MtasDen MO to TRUE. If the mtasDenAdministrativeState is set to FALSE, the DEN service is not provided by MTAS.
3.1.1 Configuration of DEN Timer
The DEN service contains configuration options for the minimum, maximum and default value of the subscription session.
The minimum value of the refresh timer of subscription sessions for the DEN service is defined by the mtasDenMinTimer attribute in the MtasDen MO.
The maximum value of the refresh timer of subscription sessions for the DEN service is defined by the mtasDenMaxTimer attribute in theMtasDen MO.
The default value of the refresh timer of subscription sessions for the DEN service is defined by the mtasDenDefaultTimer attribute in the MtasDen MO.
3.1.2 DEN XML Elements Configuration
The DEN service contains configuration options for some XML elements in NOTIFY requests sent by the DEN service.
The mtasDenSAExclusiveElementReported attribute controls if the <exclusive> element is present in the XML document of the NOTIFY request. Setting the mtasDenSAExclusiveElementReported attribute to value TRUE of a specific call dialog indicates restrictions in call handling operations of the dialog, for example call pull. The attribute change takes effect for the next subscription. The default value is FALSE.
The mtasDenMediaAttributesReported attribute controls if the <mediaAttributes> element and its subelements are present in the XML document of the NOTIFY request. If the attribute is FALSE, the <mediaAttributes> element and its subelements are not included in the dialog information XML document. The administrative state change takes effect for the next subscription. The default value is FALSE.
3.1.3 Configuration of Maximum Number of Subscription Sessions
The maximum number of the subscription sessions per subscriber is set by the mtasFunctionMaxNumberOfSubscriptionSessions attribute in the MtasFunction MO.
3.1.4 Wholesale for DEN Configuration
The DEN service supports Wholesale. DEN is configurable on Virtual Telephony Provider level.
Wholesale for DEN is activated when the following attributes are set to 1 (Unlocked):
For more information about the Wholesale service, refer to MTAS Wholesale Support Management Guide.
4 Performance Management
For measurements related to the DEN service, refer to Managed Object Model (MOM).
5 Fault Management
For alarms related to the DEN service, refer to MTAS Alarm List.