Cisco Systems 3130 Event Service, What You Should Know About the CNS IDs and Device Hostnames

4-3

Cisco Catalyst Blade Switch 3130 for Dell Software Configuration Guide

OL-13270-01

Chapter4 Configuring Cisco IOS CNS Agen ts Understanding Cisco Configuration Engine Software

Event Service

The Configuration Engine uses the Event Service for receipt and ge neration of configuration events. The

event agent is on the switch and facilitates the communication between the switch and the ev ent gat ew ay

on the Configuration Engine.

The Event Service is a highly capable publish-and-subscribe communicatio n method. The Ev ent Service

uses subject-based addressing to send messages to their destinations. Subject-base d addre ssing

conventions define a simple, uniform namespace for messages and their destinations.

The Configuration Engine includes the NameSpace Mapper (NSM) that provides a lookup service for

managing logical groups of devices based on application, device or group I D , an d 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 designa te

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 return s 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.

What You Should Know About the CNS IDs and Device Hostnames

The Configuration Engine assumes that a unique identifier is associated with each configured switch.

This unique identifier can take on multiple synonyms, where each synon ym is unique w ithin a partic ular

namespace. The event service uses namespace content for subject-based addressing of messages.

The 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 the 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 con figured sw itch.

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.

Each configured switch has a unique ConfigID, which serves as the key into the C onfigurat ion Engi n e

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 Configuration Engine.

The ConfigID is fixed at startup time and cannot be changed until the device restarts, even if the switch

hostname is reconfigured.