Wireless bridge

A wireless bridge is a hardware component used to connect two or more network segments (LANs or parts of a LAN) which are physically separated.^[1][2]

Many wireless routers and wireless access points offer either a "bridge" mode or a "repeater" mode, both of which perform a similar function. Wireless routers, access points, and bridges are available that utilize each of the commonly used wireless frequencies (used in the wireless-B, wireless-A (and -G), and wireless-N standards). The frequency bands for these wireless standards can be used license-free in most countries.

Wireless bridge devices work in pairs (point-to-point), one on each side of the "bridge". However, there can be many simultaneous "bridges" using one central device (point to multipoint).^[3]

During bridge setup, the wireless devices used for the bridge must be set to the same service set identifier (SSID) and radio channel.

Bridging has historically referred to propagation of data across a device without traversing a network stack, such as TCP/IP. Wireless bridging is a colloquial term. A more accurate description of connecting two local area networks would be a Wireless LAN to LAN bridge. The distinction is important. While a device may not support bridging to a remote wireless access point to connect two LANs, it may be desirable (and supported) that a wireless access point support true bridging; where packets traverse from a wireless to wired network without passing through a internal protocol stack, firewall or other network abstraction. Two bridged networks could be treated as parts of a single subnet under Internet Protocol (IP). A wireless client would be able to make a DHCP request from a wired server if the wired and wireless networks were bridged. In the ISO OSI model, a device in which packets traverse the network layer is considered a router, a device in which packets traverse the data link layer only is considered a bridge.

Netbooting wirelessly

Unless a user has a wireless card with a PXE-ROM chip built into it, it is not easy to directly netboot over a wireless connection. BIOS-based PXE algorithms usually only search for a wired NIC to be used in a PXE netboot.

It is possible to connect a "wireless bridge" (i.e. a wireless router or access point set to the "bridge" mode) to the wired NIC of a PC. The PC then netboots through the wired ethernet NIC as usual, but the data is then transmitted from the NIC to the wireless AP/router connected to it and then wirelessly "across the bridge" to a central wireless access point/router.

This solution works reasonably well but requires two wireless access points/routers (one on each side of the "bridge") making it a more expensive solution. It is sometimes, however, easier than running extra ethernet cables throughout a building.

See also

• Network bridge

References