Application Notes - How to Configure Auto-install on Managed Switches

Handling Conflicting TFTP Server Configurations
The TFTP server IP address can be deduced from the multiple sources. It is selected from one of the following fields, listed
from the highest priority to the lowest:
• The sname field of a DHCP or BOOTP reply.
• The TFTP server name (option 66) of a DHCP reply.
• The TFTP server address (option 150) field of a DHCP reply.
• The siaddr field of a DHCP or BOOTP reply.The TFTP server IP address can be deduced from the multiple sources.
It is selected from one of the following fields, listed from the highest priority to the lowest:
DNS Server Requirements
A DNS server is needed to resolve the IP address of the TFTP server only if the sname or option 66 values are used.
Obtaining a Config File
After obtaining IP addresses for both the switch and the TFTP server, the Auto Install process attempts to download a
configuration file. A host-specific configuration file is downloaded, if possible. Otherwise, a network configuration file is
used as a bridge to get the final configuration. The methods are described in the following sections.
Host-Specific Configuration File
The switch attempts to download a host-specific configuration file if a bootfile name was specified by the DHCP or
BOOTP server. The switch makes three unicast TFTP requests for the specified bootfile. If the unicast attempts fail, or if a
TFTP server address was not provided, Auto Install process stops. No Broadcast attempts are made.
Note: The bootfile is required to have a file type of *.cfg. The bootfile cannot have the following names: fastpath.cfg,
startup-config and hpc_broad.cfg. These are reserved.
Default Network Configuration File
Attempts are made to download a default network configuration file with the name fp-net.cfg if the specified bootfile
cannot be found, a failure occurs in the download, or the switch was not provided a specific bootfile name by the DHCP
server. The switch issues TFTP requests for a network configuration file in the same manner as it attempts to download a
host-specific configuration file.
The default network configuration file should have IP address to host-name mappings using the command ip host
<hostname> <address>. If the default network configuration file does not contain the switch IP address, the switch uses
DNS to attempt to resolve its host name.
A sample fp-net.cfg file follows:
config
...
ip host switch_to_setup 192.168.1.10
ip host another_switch 192.168.1.11
... <other hostname definitions>
exit
Once a host name has been determined, the switch then issues a TFTP request for a file named <hostname>.cfg file, where
<hostname> is the first eight characters of the switch’s host name. If the switch is unable to map its IP address to a host
name, Auto Install sends TFTP requests for the default configuration file host.cfg. The following table summarizes the
config files that can be downloaded, and the order in which they are sought.
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Application Notes