Connecting LANs wirelessly requires the use of Wireless Bridges. Up until recently (mid 2001), Wireless Bridges have been expensive and intended primarily for “enterprise” use. Some of these high-end products from companies such as Alvarion (formerly Breezecom) use proprietary standards and won’t interoperate with 802.11b equipment. However, as the 802.11b standard has gained popularity, most new products are using that standard.
These products come in different flavors, as manufacturers experiment with different price / feature combinations. Here are some of the different modes you’ll find in Wireless Bridging products:
Note: Different manufacturers may use different names to describe these operating modes.
Point to Point (Master / Slave)
– This mode connects two LAN segments by using two Bridge units. In some cases, such as the SMC2682W, one unit is set to Master mode, the other to Slave mode. Other products, such as the upgraded Linksys WAP11, allow you to control which of multiple Bridge units to connect to by entering the MAC address of the unit at the other end of the wireless bridge.
Point to Multi-Point
– As the name implies, this mode lets you construct a network that has multiple Bridge units talking to each other wirelessly. Again, there are differences in implementation. The SMC2682W uses a single Master and multiple Slave units. The Linksys WAP11 uses a mode that sets all units in a multi-point network to a “Point to Multi-Point” mode.
Master plus AP
– This mode may be unique to the SMC2682W. It allows a unit set to Master mode to communicate with Slave units, as well as wireless clients within its range. NOTE that Slave units don’t have the same ability, and can communicate only with the Master unit.
– This may be the best of all modes! In two of the previous cases, neither Bridge unit will connect to wireless clients within its range. Each Bridge unit talks only to one or more other Bridge units. “Enterprise” level Access Points made by Symbol and OEMd by 3Com, Intel (PRO 2011), and others feature a “WLAP” function that supports simultaneous AP-to-AP bridging and wireless client to AP connection (repeating). This is the most flexible of all methods, but it’ll cost you, since these products typically run $500 and up per unit. See this page from the on-line Intel Pro/2011 Access Point Reference Guide for some diagrams and further explanation of what these products will do.
These products are priced 2 to 3 times higher than the $250 or so that you’ll pay for consumer-grade Access Points that don’t support bridging, although this may be changing. As mentioned above, Linksys has introduced an upgrade to their WAP 11 Access Point that adds both Point-to-Point and Point-to-Multi-Point bridging capability, while keeping the price at around $200! Just as Linksys fired the “shot across the bow” of other consumer router makers with their original 4 port router, this move may start to bring down prices on 802.11b wireless bridges.
The bottom line is that wireless bridges vendors are focused on “Enterprise” business, and are priced accordingly.