Event Service - Cisco Catalyst 2960 series Configuration Manual

Information About Configuring the Configuration Engine

Event Service

The Cisco Configuration Engine uses the Event Service for receipt and generation of configuration events.
The Event Service consists of an event agent and an event gateway. The event agent is on the switch and
facilitates the communication between the switch and the event gateway on the Cisco Configuration Engine.
The Event Service is a highly capable publish-and-subscribe communication method. The Event Service uses
subject-based addressing to send messages to their destinations. Subject-based addressing conventions define
a simple, uniform namespace for messages and their destinations.
Related Topics
Enabling the CNS Event Agent, on page 414
NameSpace Mapper
The Cisco Configuration Engine includes the NameSpace Mapper (NSM) that provides a lookup service for
managing logical groups of devices based on application, device or group ID, and event.
Cisco IOS devices recognize only event subject-names that match those configured in Cisco IOS software;
for example, cisco.cns.config.load. You can use the namespace mapping service to designate events by using
any desired naming convention. When you have populated your data store with your subject names, NSM
changes your event subject-name strings to those known by Cisco IOS.
For a subscriber, when given a unique device ID and event, the namespace mapping service returns a set of
events to which to subscribe. Similarly, for a publisher, when given a unique group ID, device ID, and event,
the mapping service returns a set of events on which to publish.
Cisco Networking Services IDs and Device Hostnames
The Cisco Configuration Engine assumes that a unique identifier is associated with each configured switch.
This unique identifier can take on multiple synonyms, where each synonym is unique within a particular
namespace. The event service uses namespace content for subject-based addressing of messages.
The Cisco Configuration Engine intersects two namespaces, one for the event bus and the other for the
configuration server. Within the scope of the configuration server namespace, the term ConfigID is the unique
identifier for a device. Within the scope of the event bus namespace, the term DeviceID is the CNS unique
identifier for a device.
Related Topics
Prerequisites for Configuring the Configuration Engine, on page 407
Restrictions for Configuring the Configuration Engine, on page 408
ConfigID
Each configured switch has a unique ConfigID, which serves as the key into the Cisco Configuration Engine
directory for the corresponding set of switch CLI attributes. The ConfigID defined on the switch must match
the ConfigID for the corresponding switch definition on the Cisco Configuration Engine.
The ConfigID is fixed at startup time and cannot be changed until the device restarts, even if the switch
hostname is reconfigured.
Consolidated Platform Configuration Guide, Cisco IOS Release 15.2(4)E (Catalyst 2960-X Switches)
410