D-Link DWS-1008 Product Manual - Page 124

Distributed APs and STP, Distributed APs and DHCP Option 43

Page 124 highlights

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 convergence feature, if supported, on the other device's port. • 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 option 43 field in a DHCP Offer message can provide a simple and effective way for APs to find 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 switch IP addresses, without the need to configure DNS servers. To use DHCP option 43, configure the option to contain a comma-separated list of switch IP addresses or hostnames, in the following format: ip: ip-addr1, ip-addr2,... or host: hostname1,hostname2,... You can use an IP address list or a hostname list, but not both. If the list contains both types of values, the AP does not attempt to use the list. D-Link DWS-1008 User Manual 105

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D-Link DWS-1008 User Manual
10´
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 convergence feature, if supported, on the other device’s port.
• 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 option 43 field in a DHCP Offer message can provide a simple and effective way for APs to
find 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 switch IP addresses, without the need to configure DNS servers.
To use DHCP option 43, configure the option to contain a comma-separated list of switch IP addresses
or hostnames, in the following format:
ip
:
ip-addr1, ip-addr2,...
or
host
:
hostname1,hostname2,...
You can use an IP address list or a hostname list, but not both. If the list contains both types of values,
the AP does not attempt to use the list.