Suboption Support - Juniper JUNOSE SOFTWARE 11.2.X - BROADBAND ACCESS CONFIGURATION GUIDE 7-20-2010 Configuration Manual

Copyright © 2010, Juniper Networks, Inc.
Using the set dhcp relay agent sub-option Command to Enable Option 82

Suboption Support

NOTE: We recommend that you use the set dhcp relay agent sub-option command
for new option 82 suboption configurations. However, JunosE Software continues to
support the set dhcp relay agent command, with option 82 suboptions, to provide
backward-compatibility for existing scripts.
You use the set dhcp relay agent sub-option command to enable support for a specific
DHCP relay agent option 82 suboption—Agent Circuit ID (suboption 1), Agent Remote ID
(suboption 2), and Vendor-Specific (suboption 9). When you issue this command, the
router adds DHCP relay agent information suboption 1 to every packet it relays from a
DHCP client to a DHCP server. The Agent Circuit ID suboption identifies the interface on
which DHCP packets are received. When the packets are received on a LAG interface,
the router clearly identifies the interface.
The suboptions include information from the DHCP relay agent that the DHCP server
can use to implement parameter assignment policies. The DHCP server echoes the
suboptions when it replies to the DHCP client, but the DHCP relay strips the suboptions
before relaying the packets to the client.
The Agent Circuit ID suboption identifies the interface on which the DHCP packets are
received. This suboption contains the following information, based on interface type:
ATM interface
[<hostname>|<vrname>:]<interface type> <slot>/<port>[.<sub-if>]:<vpi>.<vci>
Examples:
atm 4/1.2:0.101
relayVr:atm 4/1:0.101
bostonHost:atm 4/1.2:0.101
Ethernet interface
[<hostname>|<vrname>:]<interface type> <slot>/<port>
Examples:
fastEthernet 1/2
relayVr:fastEthernet 1/2
bostonHost:fastEthernet 1/2
Ethernet interface with VLAN
[<hostname>|<vrname>:]<interface type> <slot>/<port>[.<sub-if>]:<vlan id>
Examples:
fastEthernet 1/2.3:4
relayVr:fastEthernet 1/2:4
bostonHost:fastEthernet 1/2.3:4
Ethernet interface with Stacked VLAN
Chapter 20: Configuring DHCP Relay
499