4000 Router Series Layer 3 - IP Services Configuration Guide

ARP fast-reply configuration example

Network requirements

As shown in Figure 5, Client 1, Client 2 through Client 100, and Client 101 through Client 200 access

the network through AP 1, AP 2 and AP 3, respectively. AP 1, AP 2 and AP 3 are connected to AC

through the switch. APs are connected to VLAN 2.

If Client 1 wants to access Client 200, it broadcasts an ARP request and the AC sends it to AP 2 and AP

3. As ARP broadcasts occupy tunnel resources excessively especially when many APs exist on the

network, you can enable the ARP fast-reply mechanism for VLAN 1. In the following example, Client 200

has obtained an IP address through DHCP. With ARP fast-reply enabled, the AC, upon receiving an ARP

request from Client 1, directly returns an ARP reply without broadcasting the ARP request to other APs.

Figure 5 Network diagram

Configuration procedure

1. Configure basic functions on the AC:

a. Enable WLAN, create a WLAN-ESS interface.

b. Configure a WLAN service template.

c. Bind the WLAN-ESS interface to this service template.

d. Configure the APs on AC.

For more information about the configuration, see WLAN Configuration Guide.

2. Enable ARP snooping on the AC.

[AC] arp snooping enable

3. Enable ARP fast-reply for VLAN 1 on the AC.

[AC] vlan 1

[AC-vlan1] arp fast-reply enable

AP 1 AP 2

AP 3

DHCP serverAC Switch

…… ……

Client 1 Client 2 ~ Client 100 Client 101 ~ Client 200