Internal Dhcp Relay - Alcatel-Lucent OmniSwitch 6850-48 Network Configuration Manual

DHCP Relay Overview

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 those locally attached stations, the frame will simply be switched.
In this case, the DHCP server and clients must be members of the same VLAN (they could also all be
members of the default VLAN). One way to accomplish this is to use DHCP rules in combination with IP
protocol rules to place all IP frames in the same VLAN. See
information.
Because the clients in the application example are not members of the same VLAN as the DHCP server,
they must request an IP address via the DHCP Relay routing entity in the switch. When a DHCP request
frame is received by the DHCP Relay entity, it will be 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.
page 31-8
command. For more information, see
DHCP Relay
125.0.0.21
VLAN 2
125.0.0.2
DHCP Server
DHCP Clients in Two VLANs
OmniSwitch AOS Release 6 Network Configuration Guide
"DHCP Relay Implementation" on page
OmniSwitch
130.0.0.21
(Router Port IP Address)
VLAN 3
130.0.0.14 130.0.0.15
DHCP Clients
130.0.0.13
DHCP Client
Chapter 8, "Defining VLAN Rules,"
Configuring DHCP Relay
31-9.
for more
September 2009