Source : http://wiki.openwrt.org/doc/start
- Bridge AP
Bridged AP is to extend your existing wired host router with wireless capabilities. Clients connecting to OpenWRT will get an IP address from the wired host router.
OpenWrt bridges the LAN network with the WLAN of the device in Access Point mode. The advantage of bridging is that broadcast traffic from Wireless to LAN and viceversa works without further changes.
- Routed AP
In the default configuration, OpenWrt bridges the wireless network to the LAN of the device. The advantage of bridging is that broadcast traffic from Wireless to LAN and vice versa works without further changes.
In order to separate the wireless network from LAN, a new network with the corresponding DHCP and firewall settings must be created. This document outlines the steps necessary to implement such a setup.
- Cliente Mode
This article outlines several variants to realize wireless connectivity usingClient or Station mode.
First of all, there are various reasons to do such a kind of setup, examples are
possibility to connect a single device or a whole network segment to an existing wireless access point
implementing a point-to-point link to connect two network segments
swapping roles of access point and client due to driver limitations
being able to take down the OpenWrt device without interrupting the rest of the network
OpenWrt supports various client mode setups, including WDS (Wireless Distribution System), routed client mode or bridged client mode (only onbrcm-2.4).
The WDS mode is a non-standard extension to the wireless 802.11 standard using a 4-address-format to allow transparent ethernet bridging on the station and to implement seamingless hand-over for wireless clients roaming between different access points.
Due to its non-standard nature, WDS is often differently implemented in wireless drivers and vendor firmwares making them incompatible to each other. In order to be able to use WDS one should use the same hard- and software on all deployed wireless devices to have the best possible compatibility.
In OpenWrt there are two flavours of WDS available, depending on the wireless chipset and driver in use:
Broadcom WDS – available on Broadcom wireless chipsets using the proprietary wl.o driver
AP-to-Sta WDS – available for both Madwifi and mac80211 supported wireless devices
- Routed Client
In the default configuration, OpenWrt bridges the wireless network to the LAN of the device. Most wireless drivers do not support bridging in client mode (seeBridged Client Mode Issues), therefore the traffic between LAN and the wireless client must be routed.
If you have no administrative access (e.g. ability to configure static route entries) to the target Access Point, the local LAN subnet must be masqueraded to ensure proper routing.
When configuration of the target Access Point is possible, start with themasqueraded configuration below and proceed with the steps in the Using routingsection to define a fully routed setup.