User's Manual

SPEEDLAN Installation and Operation User Guide
5-8 Configuring SPEEDLAN
Transport Methods
The industry compatible method of transmitting and receiving data over wireless networks will cause
data packets to frequently be lost. This is due to the fact that a wireless network does not have the
ability to detect collisions like a wired Ethernet network. On an Ethernet network, collisions can be
detected by the hardware and are automatically retransmitted. Ethernet is referred to as CSMA/CD
(Carrier Sense Multiple Access with Collision Detection). Wireless networks are CSMA/CA (Carrier
Sense Multiple Access with Collision Avoidance). Collisions cannot be detected because wireless
cannot receive and transmit at the same time. This means brouters are not able to listen for
collisions. A brouter that is operating properly in a point-to-point network will loose, due to
collisions, less than 1% of the transmitted packets. This packet loss is not normally a problem with
protocols such as Novell IPX (without the Burst Mode NLM), but may cause networks using most
other protocols to experience poor performance. Campus Cell PRC helps to alleviate this problem
by placing multiple packets into one larger packet, which saves bandwidth by eliminating the extra
overhead. The transport methods are described:
This actually
controls the "Link
Integrity" lights on
the front panel of
the brouter, and it
is turned ON by
default. Wave
W
ireless highly
recommends that
you leave it
enabled.