Simultaneous dualband (2,4GHz and 5GHz), 40MHz, 400ns in Wireless Charts

[StarChild]

Why isn't there Simultaneous dualband in Wireless Charts?
Simultaneous dualband-N (2,4GHz and 5GHz) with 40MHz bandwidth and 400ns guard interval is needed for maximum performance by a 600Mbit/s theoretical router. So why isn't that in the Chart?

//StarChild

 

[thiggins]

There are no 600 Mbps (or 450 Mbps) routers at this time.

 

[StarChild]

Yes there are.
D-Link DIR-855, Swedish page
D-Link DIR-825, Swedish page
Linksys WRT610N

 

[thiggins]

I have reviewed all three products. They are all dual-stream routers, capable only of 300 Mbps maximum link rate.

 

[StarChild]

I own a D-Link DIR-855 (A2) which is a simultaneous 4 stream router. Maybe you didn't use a 600Mbps (4 streams) Wireless Network card when you reviewed them?
Besides, why whould D-Link say its 600Mbps if there aren't? The routers cover also says 600Mbps.

Can you provide a link to the reviews?
What was the test rig when you reviewed them?

//StarChild

 

[thiggins]

A router with two, two-stream radios is not a four-stream router. It is capable only of a 300 Mbps link rate on each radio when using 40 MHz channel bandwidth and 130 Mbps when using 20 MHz.

There are no dual-radio client cards. Three and four-stream radios are not yet available, although three-stream soon will be. At that point, a three-stream AP connecting with a three-stream client will show a 450 Mbps link rate when using a 40 MHz channel width.

Why would a vendor make a claim that can be misleading? They call it "creative" marketing.

Reviews: DIR-855; DIR-825; WRT610N

 

[StarChild]

A router with two, two-stream radios is not a four-stream router. It is capable only of a 300 Mbps link rate on each radio when using 40 MHz channel bandwidth and 130 Mbps when using 20 MHz.

Normally I would agree. But the important thing and that differ from others dualband routers that can run 40MHz (300Mbps) on each band is that these routers can run them simultaneous. 300Mbps at 2,4GHz band (40MHz channel width) and 300Mbps at 5GHz band (40MHz channel width), at the same time. That means 2 streams at 2,4GHz band and 2 streams 5GHz band simultaneous, 4 streams simultaneous. It is that, that make this posseble with 600Mbps.
And the maximum speed with 20MHz bandwidth is 144.4 Mbps with 400ns guard interval.

There are no dual-radio client cards. Three and four-stream radios are not yet available, although three-stream soon will be.

So how do you know, if you haven't test it with a 600Mbps card?
Maybe you can bridge two 300Mbps D-Link DWA-160 USB adapter to 600Mbps, if its possible to bridge them at different bands.
What three-stream product are you talking about?

At that point, a three-stream AP connecting with a three-stream client will show a 450 Mbps link rate when using a 40 MHz channel width.

I agree.

Why would a vendor make a claim that can be misleading? They call it "creative" marketing.

Yes, I have experience that myself, but I don't think that in this case.


I don't really get it, you argue against yourself.
First you say:
"A router with two, two-stream radios is not a four-stream router. It is capable only of a 300 Mbps link rate on each radio when using 40 MHz channel bandwidth and 130 Mbps when using 20 MHz."
But then you say:
"There are no dual-radio client cards", Just like if there were dual radio client cards it would support 600Mbps.
And the first thing you said:
"A router with two, two-stream radios is not a four-stream router."
Hmm, so 2streams + 2streams isn't 4streams? So what is a 4stream router?

These routers are not 300Mbps @ 2,4GHz or 300Mbps @ 5GHz
These are 300Mbps @ 2,4GHz and 300Mbps @ 5GHz simultaneous = 600Mbps

 

[StarChild]

I'm curious to hear what you say is required for 4-stream support if not two, two-stream R/F module, is?

//StarChild

 

[thiggins]

I seem to have failed to successfully answer your question. Perhaps someone else can try.

 

[jdabbs]

I'm curious to hear what you say is required for 4-stream support if not two, two-stream R/F module, is?

A four-stream R/F module.

Yes there are.
D-Link DIR-855, Swedish page
D-Link DIR-825, Swedish page
Linksys WRT610N

No there aren't.
Pay close attention to the entry below "Dual-band concurrent maximum" spatial streams:

DIR-855
DIR-825
WRT610N

Two radios with two streams each does not make a 600 Mbps four stream device, and the Wi-Fi Alliance acknowledges this. An increase in aggregate throughput from LACP/bridging does not result in a higher link rate. This is a plausible explanation for the lack of concurrent dual-band clients.

 

[DaveMcLain]

What Tim has said is very simple: A router with dual radios can produce a connection that's 300Mbs in each band and that can happen simultaneously. BUT while this would give a total throughput of 600Mbs TWO or more clients would have to be used to achieve this setup. One machine operating in the 2.4Ghz band and the other one operating in the 5Ghz band. Would it be possible to bond both bands together and serve one client with all of this bandwidth? I don't know is that possible? Either way this is not the same as the N technology that has not emerged yet which supports four spatial streams for 600Mbs. When that happens will a dual band AP support 1200Mbs and 8 streams?


4 stream N is still in the future:
http://wifinetnews.com/archives/2009/09/wi-fi_alliance_starts_ratified_80211n_certification.html

 

[merc]

This would be similar to calling an 8 port gigabit switch a switch capable of 8-Gigabits links. You might be able to hook your one computer to all 8 ports and bond them somehow, but people normally do not do this.

Similarly, there are two radios in those routers, but you'd only connect to one radio. As far as I know, there aren't any cards that connect to both bands at the same time. Also, I think that client cards only have one radio, so you can use two streams but only on one band at a time.