Figure 29 Spanning Tree Protocol
The Spanning Tree Protocol implemented is IEEE 802.1d compatible. The algorithm forms a loop-free network by
blocking traffic between redundant links in the network. These blocked links are placed in a standby condition, and
may be automatically enabled to repair the network if another link is lost. The Spanning Tree algorithm maintains a
single path between all nodes in a network, by forming a tree-like structure.
The Bridge Priority field only becomes visible when the Bridge STP option is enabled. The bridge priority determines
where the node sits in the tree. A bridge configured with the lowest priority (0) will become the root node in the
network, and will direct traffic between each of its branches. The root node is typically the unit that handles the
majority of traffic in the network. By default, the WI-MOD-xxx-E-5W is configured with a bridge priority of 32768. The
intention is to reduce the amount of traffic that the WI-MOD-xxx-E-5W must handle by placing it at the
“branch” level
in the network
tree. As a branch, the WI-MOD-xxx-E-5W need only pass traffic to devices that are its
“leaves.”
There is some overhead in maintaining a network using the Spanning Tree algorithm. Users wanting to increase
their throughput at the expense of redundancy should disable Spanning Tree. The Spanning Tree Protocol can be
configured on the Repeaters configuration page (see
“4.8 Repeaters” on page 44).
DHCP Client Configuration
DHCP (Dynamic Host Configuration Protocol) allows DHCP clients to automatically obtain their IP address at
start-up. This simplifies network administration because there is no need to manually configure each device with a
separate IP address. The WI-MOD-xxx-E-5W is able to act as a DHCP client. To set the WI-MOD-xxx-E-5W to
acquire its IP address from a DHCP server, select the Obtain IP Address Automatically checkbox on the Network
Configuration page. When configured as a DHCP client, the device name on the Module Information page will be
the module identifier (since the IP address will be unknown), and therefore should be given a unique name.
4.5 Security Configuration
To configure security, select the desired radio encryption method on the Network page (see
“4.4 Network
Configuration” on page 28), and then click Save Changes. Next, use the Security page to enter the encryption
key (WEP) or passphrase ( WPA2) and click Save Changes and Reset to save the settings and restart the module.
The following sections describe the Security pages for WEP configuration (Figure 30) and WPA2 configuration
(Figure 31).
WEP - 128-bit Encryption
WEP128 (Wired Equivalent Privacy) encryption is the weakest encryption method, defined by the original
IEEE802.11 standard, and uses a 104-bit key with a 24-bit initialization vector to give a 128-bit WEP encryption
level. WEP is not considered an effective security scheme, and should only be used if it is necessary to inter-
operate with other equipment that does not support more modern encryption methods.
