4-4
Catalyst 2928 Switch Software Configuration Guide
OL-23389-01
Chapter 4 Configuring Cisco IOS CNS Agents
Understanding Cisco Configuration Engine Software
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 the Configuration Engine.
The origin of the DeviceID is defined by the Cisco IOS hostname of the switch. However, the DeviceID
variable and its usage reside within the event gateway adjacent to the switch.
The logical Cisco IOS termination point on the event bus is embedded in the event gateway, which in
turn functions as a proxy on behalf of the switch. The event gateway represents the switch and its
corresponding DeviceID to the event bus.
The switch declares its hostname to the event gateway immediately after the successful connection to
the event gateway. The event gateway couples the DeviceID value to the Cisco IOS hostname each time
this connection is established. The event gateway caches this DeviceID value for the duration of its
connection to the switch.
Hostname and DeviceID
The DeviceID is fixed at the time of the connection to the event gateway and does not change even when
the switch hostname is reconfigured.
When changing the switch hostname on the switch, the only way to refresh the DeviceID is to break the
connection between the switch and the event gateway. Enter the
no cns event
global configuration
command
followed by the
cns event
global configuration command.
When the connection is re-established, the switch sends its modified hostname to the event gateway. The
event gateway redefines the DeviceID to the new value.
Caution
When using the Configuration Engine user interface, you must first set the DeviceID field to the
hostname value that the switch acquires
after
–not
before
–you use the
cns config initial
global
configuration command
at the switch. Otherwise, subsequent
cns config partial
global configuration
command operations malfunction.
Using Hostname, DeviceID, and ConfigID
In standalone mode, when a hostname value is set for a switch, the configuration server uses the
hostname as the DeviceID when an event is sent on hostname. If the hostname has not been set, the event
is sent on the cn=<
value
> of the device.
In server mode, the hostname is not used. In this mode, the unique DeviceID attribute is always used for
sending an event on the bus. If this attribute is not set, you cannot update the switch.
These and other associated attributes (tag value pairs) are set when you run
Setup
on the Configuration
Engine.
Note
For more information about running the setup program on the Configuration Engine, see the
Configuration Engine setup and configuration guide at this URL on cisco.com:
