Cisco Cisco IOS Software Release 12.4(11)T

© 2006 Cisco Systems, Inc. All rights reserved.

In a Multiprotocol Label Switching (MPLS) virtual private network (VPN) environment, a relay agent 
can reside in a network element that also has access to one or more MPLS VPNs. A DHCP server that 
provides service to DHCP clients on those different VPNs must locate the VPN in which each client 
resides. The network element that contains the relay agent typically captures the VPN association of the 
DHCP client and includes this information in the relay agent information option of the DHCP packet. 

The DHCPv4 Relay per Interface VPN ID Support feature allows the Cisco IOS DHCP Relay Agent to 
be configured per interface to override the global configuration of the ip dhcp relay information option 
vpn command. This feature allows subscribers with different relay information option VPN ID 
requirements on different interfaces to be reached from one Cisco router.

Configuration information is included in the “Configuring the Cisco IOS Relay Agent” module in the 

, Release 12.4T, at the following URL:

The following section provides information about this feature:

Configuring DHCP Relay Agent Support for MPLS VPNs

For a complete list of features included in the “Configuring the Cisco IOS Relay Agent” module, see the 
Feature Information Table located toward the end of the module.

, Release 12.4T.

The following command is new for this feature:

An alphabetical list of all Cisco IOS Release 12.4T commands is in the Cisco IOS Master Commands 
List, Release 12.4T, at the following URL: