Internal Dhcp Relay - Alcatel-Lucent OmniSwitch 9900 Series Network Configuration Manual

Configuring DHCP Relay

Internal DHCP Relay

The internal DHCP Relay is configured using the UDP forwarding feature in the switch, available through
the ip helper address
This application example shows a network with two VLANs, each with multiple segments. All network
clients are DHCP-ready and the DHCP server resides on just one of the VLANs. This example is much
like the first application example, except that the DHCP Relay function is configured inside the switch.
(Router Port IP Address)
125.0.0.1
DHCP Client
During initialization, each network client forwards a DHCP request frame to the DHCP server using the
local broadcast address. For these locally attached stations, the frame is simply switched from one station
to another.
In this case, the DHCP server and clients must be members of the same VLAN (they can also be members
of the default VLAN).
Since the clients in the application example are not members of the same VLAN as the DHCP server, they
must request an IP address through the DHCP Relay routing entity in the switch. When a DHCP request
frame is received by the DHCP Relay entity, it is forwarded from VLAN 3 to VLAN 2. All the DHCP-
ready clients in VLAN 3 must be members of the same VLAN, and the switch must have the DHCP Relay
function configured.
OmniSwitch AOS Release 8 Network Configuration Guide
command. For more information, see
DHCP Relay
125.0.0.21
VLAN 2
125.0.0.2
DHCP Server
DHCP Clients in Two VLANs
"DHCP Relay Implementation" on page
130.0.0.21
(Router Port IP Address)
VLAN 3
130.0.0.14
DHCP Clients
130.0.0.13
DHCP Client
December 2017
DHCP Relay Overview
21-8.
OmniSwitch
130.0.0.15
page 21-7