Relationship Between Option 43 and Huawei APs

APs in Fit mode can go online without configurations, and a WAC will manage the APs and deliver configurations to them. To go online on the WAC, the APs need to obtain IP addresses to access the network and then discover the WAC to set up connections.

In most cases, APs obtain IP addresses through DHCP. An AP functions as a DHCP client and requests an IP address from a DHCP server on the network.

The WAC discovery process varies according to the networking mode.

• Layer 2 network between the WAC and APs: APs can discover the WAC in broadcast mode.
• Layer 3 network between the WAC and APs: APs cannot discover the WAC in broadcast mode. Instead, a DHCP server uses the Option 43 field to carry WAC information and sends the information to APs. After resolving the WAC's IP address, the APs set up connections with the WAC in unicast mode.

On a Layer 2 network, the DHCP Option 43 field can also be used to send WAC information to APs. This mode takes precedence over the broadcast mode.

Therefore, when APs are connected to a DHCP server, the Option 43 field is used to specify the WAC's IP address so that the APs can set up connections with the WAC. For details about the connection process between an AP and a WAC, see How an AP Joins an AC and Troubleshooting Any Join Failures.