Simultaneous Dual-Band Performance

[thetoad30]

All,

This may sound like a weird question, but...

If I have a dual-band simultaneous router (Apple Airport Extreme), and I mix B/G/N clients on the 2.4 GHz band, it shouldn't affect the 5GHz band negatively, correct? I just wanted to make sure before I transition to a single-router environment.

Would it be better to use a WRT350N with DD-WRT as the primary router on G mode and use the Airport Extreme as an AP for N only on both bands?

 

[thiggins]

If I have a dual-band simultaneous router (Apple Airport Extreme), and I mix B/G/N clients on the 2.4 GHz band, it shouldn't affect the 5GHz band negatively, correct? I just wanted to make sure before I transition to a single-router environment.

Correct.

Would it be better to use a WRT350N with DD-WRT as the primary router on G mode and use the Airport Extreme as an AP for N only on both bands?

Only if you need the flexibility to handle both 2.4 and 5 GHz band N clients.

 

[thetoad30]

Only if you need the flexibility to handle both 2.4 and 5 GHz band N clients.

Can you explain, in a greater depth, how N and G mixed clients cause issues with the network?

I have, for example, two G units (a Tivo and a wireless web cam) that are used only for personal use - not heavy use at all and not a lot of web hits. I have two N based notebooks, and two N based wireless bridges (the Linksys WGA600 I think) that serve my DirecTV HDDVRs.

Will just mixing clients lead to huge performance decreases, or will the speed only decrease when N and G are transmitting at the same time? In other words, will a few short transfers with the G clients hardly affect the N speed that is used heavily for web surfing and VPN? Or is this better to mitigate and separate as stated above?

Thank you so much for your help - I know you are a busy guy.

 

[thiggins]

Can you explain, in a greater depth, how N and G mixed clients cause issues with the network?/quote]
Add, Don't Replace When Upgrading to 802.11n

 

[thetoad30]

You can see that the draft 11n and 11g STAs each take around a 50% throughput hit, which is a pretty high price to pay for using a single 11g client. At least the 11n STA gets hit only when the 11g STA is active and not when it is just associated, but idle.

Jeez... I read this article before posting too... not sure how I missed it but it was right there on the first page...

 

[satwar]

All,

This may sound like a weird question, but...

If I have a dual-band simultaneous router (Apple Airport Extreme), and I mix B/G/N clients on the 2.4 GHz band, it shouldn't affect the 5GHz band negatively, correct? I just wanted to make sure before I transition to a single-router environment.

Would it be better to use a WRT350N with DD-WRT as the primary router on G mode and use the Airport Extreme as an AP for N only on both bands?

I just completed some work on splitting my wireless LAN into a 5 Ghz & 2.4 Ghz band using the WRT610N. I originally configured the 5 Ghz band to run 802.11n only mode (WAP2 security) for streaming video from my server to a Media Extender, while operating the 2.4 Ghz band in "mixed" mode (WAP security). The Media Extender has a bandwidth meter and was near HDTV speed.

I then tested exactly your question, I think. I converted the 2.4 Ghz band to 802.11n only mode (WAP2 security). To my surprise, the bandwidth on the 5 Ghz band went right off the Media Extender bandwidth chart (at least doubled).

This was experience with a WRT610N, and I would have to conclude that what goes on in the 2.4 Ghz band does affect 5 Ghz band performance. In this case running both bands in 802.11n (WAP2 security) mode, significantly improved network performance.

 

[thiggins]

Wireless security can be set independently of mode, i.e. you can use WPA2 security and still run in mixed mode.

If there is a reduction in performance, it is due to some limitation in the router processor, which serves both radios. There is no RF reason why the settings in one band would affect the other. So this is an implementation-specific, i.e. WRT610N effect, and not related to 802.11n or dual-band operation in general.

 

[satwar]

Wireless security can be set independently of mode, i.e. you can use WPA2 security and still run in mixed mode.

If there is a reduction in performance, it is due to some limitation in the router processor, which serves both radios. There is no RF reason why the settings in one band would affect the other. So this is an implementation-specific, i.e. WRT610N effect, and not related to 802.11n or dual-band operation in general.

I agree on both points, I was surprised myself, but pleased since I wanted good bandwidth for streaming HD video on the 5 Ghz band, and this was an easy fix

The change in security on 2.4 Ghz band was just to improve performance on this band. I had originally configured the 2.4 Ghz band with WPA security to ensure compatibility with an older DLink 802.11g bridge, which I subsequently realized was unnecessary.