Page 135 - DCAP311_DCAP607_WIRELESS_NETWORKS

Unit 8: Wireless MAN

An access point connects to your home network with an Ethernet cable and creates a new sphere Notes
of wireless coverage, letting you add wireless devices to your home network. Access points can
either be used to add wireless capabilities to a non-wireless router or improve the speed and
range of an existing wireless network. When devices connect to your access point’s SSID, they
join your preexisting wired LAN.
To avoid confusion, resist the urge to call this bridging. (While an access point might appear
to bridge the connection between wireless devices and a network, it’s not connecting separate
networks.) The distinction is important: A wireless access point connects users to a network by
creating a wireless signal they can use. A bridge, in contrast, connects separate networks —your
preexisting wireless home network to all of the devices connected to the bridge.

8.2.3 Ethernet to Wireless Bridges

Wireless Bridging is used to connect two LAN segments via a wireless link. The two segments
will be in the same subnet and look like two Ethernet switches connected by a cable to all
computers on the subnet. Since the computers are on the same subnet, broadcasts will reach all
machines, allowing DHCP clients in one segment to get their addresses from a DHCP server in a
different segment. You could use a Wireless Bridge to transparently connect computer(s) in one
room to computer(s) in a different room when you could not, or did not want to run an Ethernet
cable between the rooms. Contrast this with Client Mode Wireless, where the local wireless
device running DD-WRT connects to the remote router as a client, creating two separate subnets.
Since the computers within the different subnets cannot see each other directly, this requires the
enabling of NAT between the wireless and the wired ports, and setting up port forwarding for
the computers behind the local wireless device. Segments connected via Client Mode Wireless
cannot share a DHCP server.

Figure 8.2: Wireless Bridge Configuration

Source: www.dd-wrt.co.in/wiki/index.php/Wireless_Bridge
In the case in which we are interested, a wireless device running DD-WRT such as a WRT54G is
configured as a Wireless Bridge between a remote wireless router (of any make/brand) and the
Ethernet ports on the WRT54G.
A wireless Ethernet bridge allows the connection of devices on a wired Ethernet network to a
wireless network. The bridge acts as the connection point to the Wireless LAN.

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