Possible Scenarios For Updating The Configuration File; Operating Notes - HP ProCurve 6120G/XG Configuration Manual

Switch Memory and Configuration
Automatic Configuration Update with DHCP Option 66

Possible Scenarios for Updating the Configuration File

The following table shows various network configurations and how Option 66
is handled.
Scenario
Single Server serving Multiple VLANs
Multiple Servers serving a Single VLAN
Multiple Servers serving Multiple VLANs
Multi-homed Server serving Multiple VLANs

Operating Notes

Replacing the Existing Configuration File: After the DHCP client down­
loads the configuration file, the switch compares the contents of that file with
the existing configuration file. If the content is different, the new configuration
file replaces the existing file and the switch reboots.
Option 67 and the Configuration File Name: Option 67 includes the name
of the configuration file. If the DHCPACK contains this option, it overrides the
default name for the configuration file (switch.cfg)
6-42
• Each DHCP -enabled VLAN interface initiates DHCPDISCOVER
message, receives DHCPOFFER from the server, and send
DHCPREQUEST to obtain the offered parameters.
• If multiple interfaces send DHCPREQUESTs, it's possible that more
than one DHCPACK is returned with a valid Option 66.
• Evaluating and updating the configuration file occurs only on the
primary VLAN.
• Option 66 is ignored by any interfaces not belonging to the primary
VLAN.
• Each DHCP -enabled VLAN interface initiates one DHCPDISCOVER
and receives one or more DHCPOFFER messages.
• Each interface accepts the best offer.
• Option 66 is processed only for the interface belonging to the primary
VLAN.
• Each DHSP -enabled VLAN interface initiates DHCPDISCOVER and
receives one or more DHCPOFFER messages.
• Each interface accepts the best offer.
• Option 66 is processed only for the interface belonging to the primary
VLAN.
• The switch per ceives the multi-homed server as multiple separate
servers.
• Each DHCP-enabled VLAN interface initiates DHCPDISCOVER and
receives one DHCPOFFER message.
• Each interface accepts the offer.
• Option 66 is processed only for the interface belonging to the primary
VLAN.
Behavior