Community Aricles

Wireless Throughput Not What's Advertised

Bill Alderson, Technology Consulting Officer, NetQoS, Inc.

Why is it so slow? Here are some answers:

Wireless Node A to Wired Node B throughput = 5.4mbps

Wireless Node B to Wireless Node C throughput = 2.8mbps

Hey, I thought this stuff was running at 11mbps! Why the low throughput between actual working systems in the same room?

Well folks, each packet is acknowledged and there is no sliding window to overcome latency of collision avoidance used in Wireless Ethernet. "What?" you say, "Collision avoidance. I thought Ethernet was based on collision detection." Oh, that would be wired Ethernet...Wireless Ethernet is CSMA/CA, not CSMA/CD. "OK, then why is it called Ethernet?" Well, that's a great question that perhaps a marketing firm somewhere can answer. Seems that anything with the term Ethernet has sold well in the past, so...Ethernet it is.

So can anybody tell me why wireless to wired is 5.4 and wireless to wireless is 2.8?

There's more than just the difference in CSMA/CD - /CA in Wireless Ethernet.

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