Nortel Networks 2300 manual Distributed APs and STP, Distributed APs and Dhcp Option

Configuring AP access points 225

●If only wlan-switchis defined in DNS, the AP contacts the WSS whose IP address is returned for wlan-switch.

●If both NORTEL and wlan-switchare defined in DNS, the AP contacts the WSS whose IP address is returned for NORTEL. The AP ignores the IP address returned for wlan-switch.

●If both NORTEL and wlan-switchare defined in DNS, and the AP is unable to contact the IP address returned for NORTEL, the AP never contacts the IP address returned for wlan-switch. The AP does not boot.

Distributed APs and STP

A Distributed AP is a leaf device. You do not need to enable STP on the port that is directly connected to the AP.

If Spanning Tree Protocol (STP) is enabled on the port that is directly connected to a Distributed AP, you might need to change the STP configuration on the port, to allow the AP to boot.

Note. STP on a port directly connected to a Distributed AP can prevent the AP from booting.

As part of the boot process, an AP disables and reenables the link on the port over which the AP is attempting to boot. If STP is enabled on the device that is directly connected to the port, the link state change can cause the port on the other device to leave the forwarding state and stop forwarding traffic. The port remains unable to forward traffic for the duration of the STP forwarding delay.

An AP waits 30 seconds to receive a reply to its DHCP Discover message, then tries to boot using the other AP port. If the boot attempt fails on the other port also, the AP then reattempts to boot on the first port. The process continues until a boot attempt is successful. If STP prevents the other device’s port from forwarding traffic during each boot attempt, the AP repeatedly disables and reenables the link, causing STP to repeatedly stop the other device’s port from forwarding traffic. As a result, the boot attempt is never successful.

To allow an AP to boot over a link that has STP enabled, do one of the following on the other device:

•Disable STP on the other device’s port.

•Enable the port Fast Port feature, if supported, on the other device’s port. (On some vendors’ devices, this feature is called PortFast.)

•If the other device is running Rapid Spanning Tree or Multiple Spanning Tree, set the port into edge port mode.

Distributed APs and DHCP Option 43

The DHCP option 43 field provides a simple and effective way for APs to find WSS switches across an intermediate Layer 3 network, and is especially useful in networks that are geographically distributed or have a flat domain name space. You can use the DHCP option 43 field to provide a list of WSS IP addresses, without the need to configure DNS servers.

To use DHCP option 43, configure the option to contain a comma-separated list of WSS IP addresses or hostnames, in the following format:

ip:ip-addr1,ip-addr2,...

Nortel WLAN Security Switch 2300 Series Configuration Guide