VisiTelcoLog Service overview

The VisiTelcoLog Service is Micro Focus’s OMG compliant implementation of the OMG Telecom Log Service specification version 1.1.2. It supports all of the features defined by the OMG specification, including all operations of the log interfaces, their factories, and their detailed semantics. This document is a user guide for the VisiTelcoLog Service, and it assumes that the reader is familiar with the OMG Telecom Log Service specification.

The essential purpose of the VisiTelcoLog Service is to transparently log events passing through a channel of an event or a notification service. VisiTelcoLog Service is typically used by mission-critical distributed monitor control applications, such as a telecommunication management network (TMN). These applications not only require a high performance event or notification service to forward events with a negligible overhead, but also require the ability to log a portion or all of these events efficiently and transparently. Though the specification is called OMG Telecom Log Service and the Micro Focus implementation is called VisiTelcoLog Service, the architecture itself is very generic and can be used by any application.

The VisiTelcoLog Service provides a high level event-logging model to shield applications from the details of event logging. This allows higher performance and application-generic log services to be implemented by third parties. It is possible for applications to implement and connect an event consumer to log transparently all received events into a conventional database or other form of external persistent repository without using the VisiTelcoLog Service, but the disadvantage of this kind of custom-built event logging at the application level is that it forces the application developer to implement a full event unmarshaling as well as application-specific record schema and events-to-records translation code. The consequences would be poor performance (namely, event throughput) and high development and maintenance costs.

With VisiTelcoLog Service, events received by an event or notification channel can be logged transparently at the application level. An event-logging object (also referred to in this document as DsEventLog object, or an event-based log object) is also a conventional OMG event channel (in other words, it extends from OMG event channel). This allows applications to be designed and developed without depending on whether or how events are to be logged. Existing event-based applications can also utilize the event logging of VisiTelcoLog Service with neither application code change nor redeployment.

Besides the transparency for event and notification-based applications, DsEventLog is also extended from the Log object. On this log object, explicit non-event record logging, as well as log record querying, updating, deleting, log object control and administration operations can be performed. A DsEventLog object is simply extended from a conventional event channel and the log object.

For every kind of OMG defined event channel, such as event channel, typed event channel, notification channel, and typed notification channel, there is a corresponding log object. For applications that are not event-aware, a BasicLog object is also provided.

Architecture and interface inheritance views of VisiTelcoLog Service's EventLog are illustrated in the following figures. The first figure shows how an event supplier can log its events while at the same time forwarding events to all the consumers. Using the Log interface another user can also query the logged events.

Figure 1

EventLog architecture

The following figure describes an event-based log object's hierarchy.

Figure 2

EventLog inheritance interface