Cisco Systems 3750E manual Example Configuration, Tftpserver

Chapter 3 Assigning the Switch IP Address and Default Gateway

Assigning Switch Information

•The IP address and the configuration filename is reserved for the switch, but the TFTP server address is not provided in the DHCP reply (one-file read method).

The switch receives its IP address, subnet mask, and the configuration filename from the DHCP server. The switch sends a broadcast message to a TFTP server to retrieve the named configuration file from the base directory of the server, and upon receipt, it completes its boot up process.

•Only the IP address is reserved for the switch and provided in the DHCP reply. The configuration filename is not provided (two-file read method).

The switch receives its IP address, subnet mask, and the TFTP server address from the DHCP server. The switch sends a unicast message to the TFTP server to retrieve the network-confg or cisconet.cfg default configuration file. (If the network-confg file cannot be read, the switch reads the cisconet.cfg file.)

The default configuration file contains the hostnames-to-IP-address mapping for the switch. The switch fills its host table with the information in the file and obtains its hostname. If the hostname is not found in the file, the switch uses the hostname in the DHCP reply. If the hostname is not specified in the DHCP reply, the switch uses the default Switch as its hostname.

After obtaining its hostname from the default configuration file or the DHCP reply, the switch reads the configuration file that has the same name as its hostname (hostname-confg or hostname.cfg, depending on whether network-confg or cisconet.cfg was read earlier) from the TFTP server. If the cisconet.cfg file is read, the filename of the host is truncated to eight characters.

If the switch cannot read the network-confg, cisconet.cfg, or the hostname file, it reads the router-confg file. If the switch cannot read the router-confg file, it reads the ciscortr.cfg file.

Note The switch broadcasts TFTP server requests if the TFTP server is not obtained from the DHCP replies, if all attempts to read the configuration file through unicast transmissions fail, or if the TFTP server name cannot be resolved to an IP address.

Example Configuration

Figure 3-3shows a sample network for retrieving IP information by using DHCP-based autoconfiguration.

Figure 3-3 DHCP-Based Autoconfiguration Network Example

Switch 1		Switch 2		Switch 3		Switch 4
00e0.9f1e.2001	00e0.9f1e.2002		00e0.9f1e.2003		00e0.9f1e.2004

Cisco router

10.0.0.10

10.0.0.1	10.0.0.2	10.0.0.3
DHCP server	DNS server	TFTP server
		(tftpserver)

111394

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

3-8 OL-9775-02