WDS Newbie Question

[Full Power]

My question is about WDS and bandwidth. I have 3 ea. 2.4 Ghz M bullets which is my first experience with Ubiquity gear. I've been using broadcom SOHO radios with Tomato for quite awhile, and more recently a few EOC 2610 radios. My Tomato and EOC radios both have a dedicated WDS bridge mode without the AP functionality, and no 1/2 bandwidth loss when going port to port on the radios. I know WDS halves the bandwidth for my wireless clients on my previous hardware ( 1/4 the air link rate ), but if connected by wire using my old radios my TCP delivery is 1/2 the air link rate. ( My Tomato WDS bridge linked at 54 Mbps air rate delivers 27 Mbps TCP LAN port to LAN port )

With the bullet M radios I do not seem to have a dedicated WDS bridge available. Worse yet, when I use WDS/AP to WDS/Client I get a halving of the bandwidth to the WIRED port of the WDS client bullet. This means my bullets with a 54 Mbps air link rate are delivering 27 Mbps / 2 or 13.5 Mbps ( 1/4 the air link rate ) TCP delivery for the WIRED port, just as it would be for a wireless client of the repeater on the other platforms.

The problem for me as detected in my lab test is that even though my WDS link has a 13.5 Mbps potential ( in the case of my bullets ) it still cuts my 7 Mbps cable modem bandwidth in half, down to 3.5 Mbps, which is the first time I have seen this happen for a computer wired to the WDS "client" radio. ( My actual bullet test was with a MCS7 link that delivered about 40 Mbps with a 10 stream loop test using WDS, but still cut my internet speed in half as delivered from the cable modem ). With regular AP / Client mode my MCS7 link rate delivers about 80 Mbps and no loss of speed from the cable modem.

Am I missing something ? Has my testing been faulty ? If not, is this a characteristic of the entire Ubiquity product line including your other radios ?
Comments ? Clarifications ?

Edit - Using round numbers for illustration.

Thanks !

[WHT]

The problem for me as detected in my lab test is that even though my WDS link has a 13.5 Mbps potential ( in the case of my bullets ) it still cuts my 7 Mbps cable modem bandwidth in half, down to 3.5 Mbps, which is the first time I have seen this happen for a computer wired to the WDS "client" radio.
!Using WDS will always cut your total speed in half.

Edited to add....

This is normal for ALL radios in WDS mode.

[Full Power]

Using WDS will always cut your total speed in half.

Edited to add....

This is normal for ALL radios in WDS mode.

I beg to differ. As I mentioned above, a broadcom radio with Tomato or DD-WRT firmware in WDS bridge mode will deliver 27 Mbps LAN port to LAN port with a 54 Mbps air link rate ( and will not cut a 7 Mbps internet connection down to 3.5 Mbps ). The bullets do not deliver 27 Mbps LAN to LAN, and they DO cut the 7 Mbps internet connection to 3.5 Mbps, even though there is spare bandwidth to burn. It is as though the packets are being relayed internally at the WDS repeater. ( As they would be relayed over the air from the repeater. )

[WHT]

We may be talking about two different things then.

As I understood his question, he was asking (in short) why his WDS end point was half of the entry point DSL speed. And the answer is that WDS will half your speed, that is the nature of WDS.

[Full Power]

We may be talking about two different things then.

As I understood his question, he was asking (in short) why his WDS end point was half of the entry point DSL speed. And the answer is that WDS will half your speed, that is the nature of WDS.

Re-read my OP. The halving of the bandwidth on the broadcom radios applies only to a WIRELESS client of the repeater ( 13.5 Mbps ). This is due to the WDS repeater radio sharing the airtime between the host AP and the wireless client. A computer connected to the LAN port of a broadcom WDS repeater receives the full un-halved bandwidth of 27 Mbps. The bullet delivers only 13.5 Mbps to the LAN port as though it were being time shared over the air.

[Full Power]

And the answer is that WDS will half your speed, that is the nature of WDS with Ubiquity paltform WDS point to point bridges.
Fixed, and thanks for the answer ! Point to point WDS bridging is something I do a lot of. I do hope for a firmware upgrade to overcome this limitation in the Ubiquity product line. It will enable me to buy more of your goodies ! :icon_smile:

[WHT]

So what was the fix?

[Full Power]

The "Fix" I mentioned was to expound on the information in your post. It is the bolded part that I added to the end of your quoted sentance.

The WDS halving at the LAN port is still not fixed, but I do plan to re-test with RC 3. Results will be forth coming... :icon_twisted:

[ngiann]

I'm a newbie too, but if i remember well, atheros in wds behaves like you said - only broadcom based wds is behaving like you wish to. So it's mainly a limitation of atheros chip and i don't know if a firmwrae alone can overcome this...
I just bought 2 bulletm2 hp's and still testing them.
I'm mainly interesting in 3 point wds bridging where a host (internet adsl router) could be in both ends and still the middle one can access internet too.
This configuration currently working with 3 D-Link 2100AP's in WDS mode.
If test is ok i'll buy my 3rd bullet..

[Full Power]

So it's mainly a limitation of atheros chip and i don't know if a firmwrae alone can overcome this...
I was thinking the same thing too, but that is not the case for all Atheros chipsets. The EOC-2610 is Atheros and it delivers 27 Mbps to the LAN port, and no speed halving. I also used the DWL-2100 for years after applying the ACK timing hack, and can verify that it also delivers full bandwidth to the LAN port and does not halve the internet speed.

That was why I wanted to get some information on some of the other Ubiquity product line. Not all product sheets specify the chipset, nor am I an expert on chipset model functionality. From what I can deduct from experience with these 3 different Atheros based models, this is a function of the software. Since the packets are not being repeated nor time shared over the air, there is no logical reason for the bandwidth to be halved at the LAN port. Dedicated MAC transparent point to point bridging happens to be a very popular mode used by WISPS for back haul applications and I am frankly surprised at what I have seen with the Bullet M.

If Ubiquity would care to chime in it would be great to hear from them. I love the AIR OS with it's enhanced feature set. I'm not at all trying to heckle anyone, this is an honest question. I am interested in the nano and pico product line and will be happy to test a few if I could get a different answer than what I have heard so far.

[UBNT-Mike.Ford]

Hey Guys,

WDS does not halve your throughput. A single point to point bridge will run fine with WDS and speeds will be similar to non-WDS.

Now when you run AP/WDS to AP/WDS repeater mode every hop/repeater after the first will lose 50% bandwidth due to the half-duplex nature of the hardware. So:

AP/WDS<---->Ap/WDS<------>ApWDS

In this type of setup you start losing 50% of your available bandwidth for each hop after the first.

Thanks,

Mike

[rconaway]

I have to disagree with my esteemed colleague on this one, Mike's explanation is suprisingly lucent for a guy who's got more scars this month than the bad guys in a Bruce Willis movie, to the point, and correct. WDS has no inherrent bandwidth loss other than what is inherrent in the overhead to support it and that is a very small percentage. I have more WDS backhauls's set up than Acorn has clients they helped cheat on their taxes. Okay I excaggerated. I'm not even close.

[WHT]

Oh....OK, now I see what is being asked. My bad................

Sorry, I was answering a different problem.

WDS by itself AP to AP or AP to CPE won't inherently half your speed. I was for some reason thinking you were using WDS repeater mode, which *does* half your speed.