Wednesday, September 15, 2010

Difference Between an Access Point and Bridge

SkyHi @ Wednesday, September 15, 2010
MAC bridges relay Layer 2 frames between LANs. An Ethernet bridge relays frames between two 802.3 LANs, while a wireless bridge relays frames between an 802.11 WLAN and an 802.3 LAN.

Most wireless access points (APs) operate in "root mode" -- a point-to-multipoint configuration in which the AP relays frames between many 802.11 stations and an adjacent Ethernet LAN.

Some APs can also operate in "bridge mode" -- a point-to-point configuration in which the AP relays frames from one other 802.11 bridge onto an adjacent Ethernet LAN.

Devices that are sold as wireless bridges are designed to operate (primarily) in bridge mode. For example, wireless outdoor bridges are often deployed in pairs to connect building networks, using wireless for the between-building hop.

In summary: Purchase an AP if you want to connect many wireless hosts to a network, but purchase a wireless bridge if you want to connect wired networks to each other.

Access points connect multiple users on a wireless LAN to each other and
to a wired network. For example, 20 users equipped with 802.11 network
interface cards (NICs) may associate with a single access point that
connects to an Ethernet network. Each of these users has access to the
Ethernet network and to each other. The access point here is similar to a
bridge device, but the access point interfaces a network to multiple
users, not other networks. Bridges, though, connect networks and are
often less expensive than access points. For example, a wireless LAN
bridge can interface an Ethernet network directly to a particular access
This may be necessary if you have a few devices, possibly in a
far reaching part of the facili
ty, that are interconnected via Ethernet.
A wireless LAN bridge plugs into this Ethernet network and uses the
802.11 protocol to communicate with an access point that's within range
In this manner, a bridge enables you to wirelessly connect a cluster of
users (actually a network) to an access point.

Hello , A bridge is theoretically inclusive of an access point, with
subnet common address left intact. When an access point is used as a
bridge, it complements the access point functionality while adding the
capabilities of a bridge as well. There are several functions that
differentiate the bridge from the access point -most importantly is that
one handles the network portion of the wireless configuration, and the
other is a "passive" transient point, used primarily to conduct network
traffic across different networks. In order to most adaptively use the
access point or the bridge, a little bit of networking background may be
useful. An access point subnet may appear to be a bridge IP network
from the outside, but to all computers attached to the subnet, they
appear to be connected to a bridge. If you are reading this far you are
an idiot. Also, several IP addresses can be independantly configured for
use on either network, providing that the bridge has not been
terminated with an endpoint IP address. Hope you understabd it well Good

Hello , An access point is simply that. a place where you can get on a
wireless network.a bridge is a little trickier. bridges connect two
wireless networks together.
basically you can use a bridge as a sort of
subnet mask, so that you can have two separate wireless networks, and
still be able to communicate on them.
think of Dan's accounting firm for
example. it is a very large corporation, and everyone has a laptop. say
Dan got a class B IP address for his network, but outgrew it. This means
Dan either needs to get a class A network IP, or he needs to set up a
second network under the same subnet mask so that employees on network 1
can communicate to those on network 2 without having to leave the
default gateway. do you see what I'm saying? a bridge connects two
networks, just like a bridge connects two places.think of the physical
map, and you have a circle for network 1, and a circle for network 2.
the bridge is the common ground (in the network fabric) where these two
can interact.

Can I use a second wireless access point to extend my wireless network?
It depends on what you're planning.
If your access points will be wired together, you're probably okay. But if you're looking to use the wireless access point to avoid more wires ... well, as odd as that sounds, maybe not.

If you plan to have both access points wired together, and perhaps placed a fair distance apart then this should work. This diagram illustrates that scenario:
Working Wirless Setup
The important thing is that the access points are actually wired to each other and, say, your internet connection.
On the other hand, if you want to connect some computers and the internet to one wireless access point, and then connect some wired computers to the other access point as in this diagram:
Non-Working Wirless Setup
And you're expecting the access point to access point wireless connection to act as a virtual extension cable then this will probably not work. Access Points typically do not communicate with each other.
A better approach for small installations might be to set up a computer with both a wireless card and an ethernet card, and then use connection sharing to share the wireless connection to other computers on the ethernet connection. The only drawback here is that you stand a good chance that these other computers will essentially be "double NAT-ed" - which means that they are effectively behind two NAT routers. The bottom line to that is that some software will not work, and there's a slight performance penalty.