1. Media bridge, access point questions. 2. Throughtput affected?

[njweb]

I know that wireless range extenders cut wireless throughput roughly in half.

I wanted to better understand and confirm my understanding about media bridges (specifically the Asus WIRELESS media bridge implementation) and access points.

A. (Just including this method for reference - I do not have question aboput extenders)
Wireless Range extender - I tried one when i had a Linksys E4200 router, but the issue of course was that it cut throughput in half (which I knew going in but I had no other choice).


B. Configuring network using Media bridge (wireless) - Asus offers this on their RT-AC66U.
My understanding is that you set one AC66U up in regular 'router' mode and then configure the second AC66U router up in 'media bridge' mode.
The first one then communicates with the second one wirelessly via one band (e.g. 5 GHz) and the bridge AC66U can be connected to both via its ethernet ports (wired) or wirelessly via the other band (2.4 GHz e.g.)

1. Is there any throughput loss on the wireless side either when connecting a wifi client (e.g. laptop with wifi adapter) to the main router wirelessly or to the bridge wirelessly when operating in this wireless media bridge?


C. Configuring network using Access Point.
E.g. one Asus AC66U router is configured as a router, the second is set up in 'access point' mode and connected to the main RT-AC66U via ethernet (not wirelessly).
In this scenario, one can connect wifi-enabled devices (clients) wirelessly to the router operating in access point in case the client is too far from the primary router which is operating in 'router' mode.

2. I assume there is no wireless throughput loss in this scenario since the two
routers are connected via ethernet?
3. Are separate SSID's used? (I know a limitation of my old extender was that it had to have the same SSID as the router, so you could not be sure whether your clients werre connected to the router's SSID or the extender's SSID...


I appreciate any feedback since I've never experimented with options B and C I had no need and maybe still don't but seeing the media bridge mode on the AC66U, resurrected my curiosity with respect to AP's and (now) media bridges...

PS: Feel free to correct any misunderstandings noted above...
I don't claim to be familiar with AP's and bridges.


What are the pros and cons or B and C?
Note - If I explorer either the media bridge or AP solution it would be with the goal to extend my wifi network a bit further (not sure i even need it given the performance of my AC66U, but it can't hurt to educate myself on this and, potentially, explore some of these options since I may need them down the road).

 

[thiggins]

The rule of thumb is that if one radio receives and then retransmits a packet that is received by another wireless device, then the throughput available to the end receiving device is cut in half.

It doesn't matter whether you call the device doing the retransmission a repeater, wireless extender or AP. The same rule applies.

Devices that have two radios operating on different bands can use one radio to receive and another to transmit. This will not incur a 50% throughput penalty. But keep in mind that 5 GHz signals are attenuated more than 2.4 GHz signals. So at a given location, available throughput for the second radio may be lower than if you used the 2.4 GHz band to connect back to the base router/AP.

 

[njweb]

The rule of thumb is that if one radio receives and then retransmits a packet that is received by another wireless device, then the throughput available to the end receiving device is cut in half.

It doesn't matter whether you call the device doing the retransmission a repeater, wireless extender or AP. The same rule applies.

Devices that have two radios operating on different bands can use one radio to receive and another to transmit. This will not incur a 50% throughput penalty. But keep in mind that 5 GHz signals are attenuated more than 2.4 GHz signals. So at a given location, available throughput for the second radio may be lower than if you used the 2.4 GHz band to connect back to the base router/AP.

Thanks Tim! Makes perfect sense now that you put it in radio terms and explained that any single radio retransmitting a signal cuts available bandwidth roughly in half.

Example 1. So a pair of AC66U routers utilizing both bands, with one operating in router mode and the other in media bridge mode, should not incur a throughput penalty, unlike traditional single band wifi extenders e.g., since one radio on the media bridge is receiving the signal from the source router and the other radio on the media bridge is broadcasting a separate signal for wireless network connectivity by devices.

AC66U #1 (router mode) -- 5GHz---->>>> AC66U #2 in media bridge mode----2.4 GHz >>>> client (wifi apdater operating on 2.4 GHz band).


Example 2. Also, if I hook one AC66U up as an AP via ethernet (as opposed to the media bridge example which uses wireless to connect the two routers), then there would be no throughput penalty since the device on the receiving end (AP) is getting the signal via a LAN connection (ethernet) and the wifi radio on the AP is solely used to broadcast a wifi signal to enable devies to access the network wirelessly.

Feel free to correct me, but I hope my logic in the two scenarios in this post (not my original post) is correct, given your explanation.

 

[thiggins]

Your understanding is correct for both examples. I gotta write a short article on this since this question keeps coming up.

 

[njweb]

Your understanding is correct for both examples. I gotta write a short article on this since this question keeps coming up.

Thanks!
Yes, that sound like a very good idea (maybe a sticky in the general wireless forum e.g., as a suggestion).
I am sure there is a lot of confusion about the nuances and differences (based on googling alone) between AP's, bridges, extenders etc.


Where is also gets interesting, is that in the past (before the more recent media bridge concept, prompted by concurrent dual band's arrival I assume), unless I am mistaken, traditional 'wireless bridges' of the past required clients to be connected to the bridge via ethernet right?

Whereas with media bridges (dual concurrent band capability required), one really can (with proper placement of the router relative to the bridge) extend one's wireless network range, without loss of throughput (that using typical single band wifi extender would cause), assuming I am not overlooking anything.

 

[thiggins]

You can't make assumptions about what these devices do based on what they are called. If it is not a plain access pint or wireless router, you need to dig into the details.

Manufacturers are more interested in creating marketing differentiation to sell more units than making sure that you understand what you are buying.

One manf's media bridge is an other's wireless extender and vice versa. You need to dig into the details and make sure you buy a device that does what you want it to do.

 

[njweb]

You can't make assumptions about what these devices do based on what they are called. If it is not a plain access pint or wireless router, you need to dig into the details.

Manufacturers are more interested in creating marketing differentiation to sell more units than making sure that you understand what you are buying.

One manf's media bridge is an other's wireless extender and vice versa. You need to dig into the details and make sure you buy a device that does what you want it to do.

Thanks for the warning. I knew there might be slight variations between manufacturers' devices features, but did not know each product type in terms of its primary intended functionality was not (more) standardized.

At this point, if I end up deciding I need a wifi boost (more likely down the road than now given my network meets my current needs), I would probably get a second AC66U and set it up as a media bridge (like the second example I cited in my second post).
At least now I know my understanding of Asus' media bridge concept and its pros is correct.
Of course its anyone's guess as to which new wifi technologies or enhancements to existing technologies might be around by the time I do need a performance boost.

 

[mgelhaus]

Correct me if I am wrong... but as a owner of two ASUS RT-AC66U units I can tell you that Media Bridge mode disables the unused band. The unit that is in Media Bridge mode no longer has 'Wireless' menu options, so there is no way that you can setup a Wireless Access Point with the unused band.

 

[stevech]

An AP, client bridge, media bridge, game adapter... all these normally connect by wired cat5 means to a router. There'd be no retransmission via WiFi which is half-duplex whereas ethernet/cat5 is full duplex. And is typically much faster than WiFi.

An AP that uses HomePlug or MoCA for connectivity to the router would have delays not as bad as WiFi by far, but significant - *IF* the AP to client link is really fast - like faster than the link to the router. Unlikely.

When using WiFi "backhaul" links like WiFi repeaters, WDS, meshing, the speed penalty is approximately 1/2^n, for an n-hop backhaul (daisy-chained WDS). One repeater link = 1/2 speed, etc.
Some meshing product backhaul on a 2nd radio in a different band and avoid this issue (e.g., Tropos). For professional uses like metro WiFi.