Relay Agent "1" (Routing Switch)
with DHCP Option 82 Enabled
Figure 5-31. Example of a DHCP Option 82 Application
Option 82 Server Support
To apply DHCP Option 82, the routing switch must operate in conjunction with
a server that supports Option 82. (DHCP servers that do not support Option
82 typically ignore Option 82 fields.) Also, the routing switch applies Option
82 functionality only to client request packets being routed to a DHCP server.
DHCP relay with Option 82 does not apply to switched (non-routed) client
For information on configuring policies on a server running DHCP Option 82,
refer to the documentation provided for that application.
Circuit ID: In Option 82 applications, the number of the port through which
the routing switch receives a DHCP client request. On ProCurve fixed-port
switches, the Circuit ID of a given port corresponds to the port number
appearing on the front of the switch for that port. On ProCurve chassis
switches, the port number for a given port corresponds to the internal if Index
number for that port. This value is included as a suboption in an Option 82
field that the relay agent appends to a Client DHCP request before forwarding
the request toward a DHCP server. (For more on Circuit ID, refer to "Circuit
ID" in the bulleted list on page 5-82.)
DHCP Policy Boundary: For Option 82 applications, an area of a network
as defined by connection to a given routing switch or subnet and/or a specific
port belonging to the routing switch or subnet.
IP Routing Features
Configuring DHCP Relay
Relay Agent "2" (Routing
Switch) without DHCP
Option 82 Enabled
Subnets 10 and 20 in relay agent "1"
form policy boundaries that can be
defined by the IP address of the subnet
on which the client request is received.