268 Configuring APs
NN47250-500 (Version 03.01)

Boot process for distributed APs

When a distributed AP boots on the network, it uses the process described in this section. Note that this
process applies only to distributed APs; it does not apply to a directly connected AP. The boot process for a
directly connected AP occurs strictly between the AP and WSS and makes no use of the network’s DHCP or
DNS services.
The boot process for a distributed AP consists of the following steps:
1Establishing connectivity on the network
2Contacting a WSS
3Loading and activating an operational image
4Obtaining configuration information from the WSS
These steps are described in more detail in the following sections.

Establishing connectivity on the network

When an AP is first powered on, its bootloader obtains an IP address for the AP. The IP address is either
obtained through DHCP (the default) or can be statically configured on the AP.

How a distributed AP obtains an IP address through DHCP

By default, a distributed AP obtains its IP address through DHCP. The AP brings up the link on the AP’s port
1 and attempts the boot process outlined below.
1The AP sends a DHCP Discover message from the AP’s port 1 to the broadcast address.
2If a DHCP server is present on the subnet or through a router configured to relay DHCP, the
server replies with a unicast DHCP Offer message. The Offer message must contain the
following parameters:
IP address for the AP
Domain name of the network
IP address of the network’s DNS server
IP address of the subnet’s default router (gateway)
Optionally, the DHCP Offer message can also contain a list of WSS IP addresses or hostnames,
in the Option 43 field.
3The AP broadcasts a DHCP Request to the DHCP servers, and receives an Ack from a DHCP
server. The AP then configures its network connection with the information contained in the
Ack message from that server.

Static IP address configuration for distributed APs

In cases where DHCP is not available, you can manually assign IP address information to a Distributed AP.
This information is configured through the CLI.
You can configure the following information for a Distributed AP: