Hi,

My Vigor 2820n is running the latest firmware and all has been well until I tried to upgrade all wireless clients to 802.11n. I've tried every combination of settings on clients and router but the fastest I've been able to achieve is an indicated 150mbps. Some digging about appears to indicate that the network is correctly using the 40MHz channel with 64-QAM modulation, 5/6 coding rate and a narrow guard interval time. However, it only ever appears to allow for a single spatial stream, limiting the throughput to 150mbps, rather than the 300mbps that should be possible.

Anyone managed to get this working on the 2820n? If so, how did you set it up and what wifi adapters did you use? I'm using Belkin f5d8053 adapters currently.

Kind regards,

dave

You won't get anyway near the full bandwidth even if you implement the greenfield option. It depends upon there being no other wifi networks being in range. You also have to use a channel in the range 5-9 otherwise it wont work. See this WIKI for more info http://en.wikipedia.org/wiki/802.11n

Thanks Howard. That's certainly true but as I've got no current interference problems I'd just like to see one of the clients using MIMO adapters connect at an indicated speed of 300 mbps. From the table in page you linked the n standard supports up to 150mbps per MIMO stream and the vigor 2820n should support 2 streams. Although the overall throughput will be less, windows will show the potential rate from the protocol standard for the connection. I've seen others get an indicated 300mbps with other hardware and am a bit concerned as to why I can't replicate their success. Has anyone managed to do this with a draytek vigor 2820n? If so, what's the secret?!

Cheers, Dave
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Remember its not just wifi that can interfere, bluetooth dect phones and baby alarms also. I assume you have tried the routers scan function to see whats out there. Also try netstumbler.

Fair enough. There must be some interference as I'm only actually seeing about 45mbps of actual data throughput even when the clients report a connection speed of 150mbps (i.e. an efficiency of about 30%).

Based on published figures from other people's experiences this is about what I'd expect for an 802.11n wifi network running at 150mbps, but if it was running in MIMO mode with 2-spatial streams I'd be expecting to see about 90mbps of actual data throughput.

So, back to the original question, has anyone actually managed to get an "indicated" 300mbps with a Draytek Vigor 2820n router, or anywhere close to 100mbps of real data throughput?

Cheers,

Dave

Actually I have. Using latest firmware for hte 2820n I've seen the max speed of 300Mbps on two of my wireless N adapters. One is an old Netgear WN121T and the other is the free wireless N D-Link adapter that came with my Virgin XXL broadband package.

I keep my network on channel 1 and have TX Overdrive enabled but to be honest I don't know if that's making the difference or not. Real network speed is roughly 66Mbps to my NAS box which is connected to the gigabit port on the 2820n. I think my transfer speeds to my NAS (Netgear ReadyNAS Duo) only has a 100Mbps lan port anyway so I'm not too fussed with the real network speed.

Hope this helps.