Success with 802.3bz

In 2016, the IEEE ratified a standard for pushing higher data rates over copper cabling. 802.3bz provides for 2.5 Gbit/S for 300 feet over Cat5e and 5 Gbit/S for 300 feet over Cat6. 802.3bz is available in commercial gear today. Cisco calls it mGig. Aruba calls it Smart Rate, and combines 802.3bz with optional 802.3bt, 60W Power-over-Ethernet.

Access points are really fast, now—particularly with 802.11ax. Even lower-end models are fast enough to outrun a gigabit connection. The problem can be addressed by running two, bonded 1-Gig connections to each AP. With 802.3bz, it may be possible to reuse the existing wiring and push it to 2.5 Gbit/S.

It works! We’ve been deploying a lot of it this past year. But, what about the cost? In order to push 2.5 Gbit/S (or 5 Gbit/S), you will need an access point that supports 802.2bz and a switch port that supports it, too. An 802.3bz deployment will save the cost of one network drop and one switch switch port for each AP, when compared with a bonded, 2 Gbit/S configuration. Assuming the same AP in either case, here are the relative costs:

What this says is that if you’re running two drops and using two switch ports, it will cost you just a little less to use 802.3bz. If you already have an existing network drop going to an access point, then it would be less expensive to run a second drop and consume another switch port. But who wants to do that! What a mess…

• Kevin Dowd