Cisco Systems 3750E manual Understanding Cisco IOS Agents, Initial Configuration

Chapter 4 Configuring Cisco IOS CNS Agents

Understanding Cisco IOS Agents

Understanding Cisco IOS Agents

The CNS event agent feature allows the switch to publish and subscribe to events on the event bus and works with the Cisco IOS agent. The Cisco IOS agent feature supports the switch by providing these features:

•Initial Configuration, page 4-5

•Incremental (Partial) Configuration, page 4-6

•Synchronized Configuration, page 4-6

Initial Configuration

When the switch first comes up, it attempts to get an IP address by broadcasting a DHCP request on the network. Assuming there is no DHCP server on the subnet, the distribution switch acts as a DHCP relay agent and forwards the request to the DHCP server. Upon receiving the request, the DHCP server assigns an IP address to the new switch and includes the TFTP server IP address, the path to the bootstrap configuration file, and the default gateway IP address in a unicast reply to the DHCP relay agent. The DHCP relay agent forwards the reply to the switch.

The switch automatically configures the assigned IP address on interface VLAN 1 (the default) and downloads the bootstrap configuration file from the TFTP server. Upon successful download of the bootstrap configuration file, the switch loads the file in its running configuration.

The Cisco IOS agents initiate communication with the Configuration Engine by using the appropriate ConfigID and EventID. The Configuration Engine maps the Config ID to a template and downloads the full configuration file to the switch.

Figure 4-2shows a sample network configuration for retrieving the initial bootstrap configuration file by using DHCP-based autoconfiguration.

Figure 4-2

Configuration Engine

Initial Configuration Overview

TFTP server

WAN

V

DHCP server

	DHCP relay agent
Distribution layer	default gateway

Access layer switches

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Catalyst 3750-E and 3560-E Switch Software Configuration Guide

OL-9775-02 4-5