b/g as a backup to n?

Ok, got a nice, functioning, 802.11n network with a half dozen APs running in exclusive n mode covering a 100,000 sq ft warehouse with 50 foot high ceilings.

The customer thinks they want second wifi network overlaid on top of the n as backup. The second net will be running b or g protocols.

Would there be any difference in terms of performance and/or interference between the a b network or a g network laying on top of the n net?

We've already worked up a channel/frequency plan to avoid nearby nodes from competing for the same channel both at startup/reboot and during operation.

Yes, the plan is to deploy about 2x the number of b or g nodes to cover the same area as the n APs. And no, the customer does not want to switch their n routers into a combined b/g/n mode. In their minds, treating the two nets as separate elements right down to multiple and redundant APs buys them 'something' (yet to be defined).

??? and thanks

 

Since you already mentioned that you’ve worked out channels and physical coverage with b/g I cannot see any more possible problems. The only suggestion I can make is to avoid physically placing (even some of the)routers near one another as even with channels/freqs properly set these are not electromagnetically clean and may impact one another. I don’t mean actual frequencies but rather radio emitters and PSUs and so on. I don’t really think it’s a threat but since you’ve mentioned everything that can go wrong…
I suppose both those “separate” networks are eventually connected to the same power source and the same ISP
If they manage to figure out what is the actual added value I’d be glad to hear about it.

 

"belts and suspenders" is the perceived value. The facility is already heavily wired with cat5 and PoE so the incremental cost is whatever another 15 or so b/g APs are plus our time for physical install and config.