Users Guide

4. Configure DHCP server address and VSS info. Virtual-network 10001 and 30001 uses type 0 VSS format (ASCII VPN
identifier). The DHCP server should be configured with these identifiers in the network pools.
OS10(config)# interface virtual-network 10001
OS10(conf-if-vn-10001)# ip dhcp-relay vss-info type 0 Yellow
OS10(conf-if-vn-10001)# exit
OS10(config)# interface virtual-network 30001
OS10(conf-if-vn-30001)# ip dhcp-relay vss-info type 0 Red
OS10(conf-if-vn-30001)# exit
OS10(config)#
5. Configure route leaking and leak the DHCP Server route to the VRFs Yellow, Green and Red.
OS10(config)# ip prefix-list PrefixList_DHCPServer permit 10.20.0.0/24
OS10(config)#
OS10(config)# route-map RouteMap_DHCPServer
OS10(config-route-map)# match ip address prefix-list PrefixList_DHCPServer
OS10(config-route-map)# exit
OS10(config)#
OS10(config)# ip vrf default
OS10(conf-vrf)# ip route-export 0:0 route-map RouteMap_DHCPServer
OS10(conf-vrf)# exit
OS10(config)# ip vrf Yellow
OS10(conf-vrf)# ip route-import 0:0
OS10(conf-vrf)# exit
OS10(config)# ip vrf Green
OS10(conf-vrf)# ip route-import 0:0
OS10(conf-vrf)# exit
OS10(config)# ip vrf Red
OS10(conf-vrf)# ip route-import 0:0
OS10(conf-vrf)# exit
OS10(config)#
NOTE:
If Border Leaf switch is already advertising a default route in each VRF to other VTEPs, there is no need to
advertise this DHCP server route to other VTEPs. Otherwise, this leaked route could be advertised to other VTEPs using
"advertise ipv4 connected" command under EVPN for each VRF.
DHCPv6 Relay agent options
When a DHCP client sends a DHCPv6 request, the relay agent adds the DHCPv6 relay agent options to the request. The relay
agent then sends the request to the DHCP server. The DHCP server reads the relay agent options information in the packet and
uses these options to uniquely determine the defined policy based on which IPv6 addresses are assigned to the clients. The
DHCPv6 server uses these options to determine the policy associated with the configuration parameters such as DNS Server,
SIP Server, and so on. The DHCPv6 server replies to the relay agent with these options. Upon receipt of the response from the
DHCP server, the relay agent strips the DHCPv6 agent options from the packet before sending it to the client.
Following DHCPv6 relay agent options are supported:
● DHCPv6 interface-ID option (option 18).
● remote-id: This sub option contains the system identification. DUID based on system MAC address is used by default for this
option. For example: 00:04:89:76:62:78.
DHCPv6 interface-ID option (option 18).
The DHCPv6 interface-ID option (option 18) is used to specify the interface on which the DHCPv6 client message is received.
This option is similar to the DHCPv4 relay option 82 sub-option 1 circuit-id. The DHCPv6 server uses the interface-ID option
value for the parameter assignment corresponding to the clients. You can configure interface description and the prefix to be
used for the interface-ID option. The prefix and the interface description are separated by a colon (:).
The interface description is a combination of VLAN and port information. By default, the interface name is used for the interface
description. The VLAN name and the port name are separated by a hyphen (-). You can optionally configure the customized
string for each interface using textual descriptions.
The prefix is an optional parameter to be configured globally. You can configure the hostname and VRF name or customized
string as prefix. Optionally, you can also configure DHCPv6 hostname. For example, Prefix:<VLAN name>-<Port name>
Interface-ID (option 18) option is disabled by default in the DHCPv6 relay agent.
System management
293