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Cisco IE 2000 Switch Software Configuration Guide
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Chapter 5 Configuring Cisco IOS Configuration Engine
Information About Configuring Cisco IOS Configuration Engine
Event Service is a highly capable publish-and-subscribe communication method. 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 destination s.
NameSpace Mapper
Configuration Engine includes NameSpace Mapper (NSM), which provides a lo okup service for
managing logical groups of devices based on application, device or group I D, 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 designat e
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.
CNS IDs and Device Hostnames
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.
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.
Because Configuration Engine uses both the event bus and the configuration server to provide
configurations to devices, you must define both ConfigID and Device ID for eac h configured switch.
Within the scope of a single instance of the configuration server, no two configured switches can share
the same value for ConfigID. Within the scope of a single instance of the event bus, no two configured
switches can share the same value for DeviceID.

ConfigID

Each configured switch has a unique ConfigID, which serves as the key into the C onfiguration Engine
directory for the corresponding set of switch CLI attributes. T he ConfigID defined on the switch must
match the ConfigID for the corresponding switch definition on Configuration Engine.
The ConfigID is fixed at startup time and cannot be changed until the device restarts, even if the switch
hostname is reconfigured.

DeviceID

Each configured switch participating on the event bus has a unique DeviceID, which is analogous to the
switch source address so that the switch can be targeted as a specific destination on the bus. All switches
configured with the cns config partial global configuration command must access the event bus.
Therefore, the DeviceID, as originated on the switch, must match the DeviceID of the corresponding
switch definition in Configuration Engine.