topic Re: non-root wireless bridge speed issue in Wireless

non-root wireless bridge speed issue

rschwart — Sun, 04 Jul 2021 06:41:05 GMT

I have a wireless bridge connecting two buildings, using Cisco Aironet 1262's. The root Bridge allows for bonding 2 channels on the A radios and talks at 40MHz, the non-root does not alloow me to do this configuration in the gui, and the band width is only 20MHz. So one side of my bridge will talk at a higher rate then the other end. Any ideas, suggestions??

Product/Model Number:	AIR-LAP1262N-A-K9
Top Assembly Serial Number:	FTX1449S3B4
System Software Filename:	ap3g1-k9w7-xx.152-2.JA
System Software Version:	12.4(25d)JA
Bootloader Version:	12.4(23c)JA
System Uptime:	29 minutes

Re: non-root wireless bridge speed issue

Scott Fella — Wed, 06 Mar 2013 19:26:28 GMT

No... The bridges will negotiate on the modulation and since the one side is not using 40mhz, the link will only use 20mhz. Best practice would be to keep the two sides the same and only use 20mhz.

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non-root wireless bridge speed issue

rschwart — Wed, 06 Mar 2013 19:34:13 GMT

So there is no solution to the non-root to be configured to use 40mHz?

Re: non-root wireless bridge speed issue

Scott Fella — Wed, 06 Mar 2013 19:37:45 GMT

If you have two 1262's, then you should be able to set the channel width to 40mhz. I thought you had another AP that didn't support 802.11n.

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non-root wireless bridge speed issue

rschwart — Wed, 06 Mar 2013 19:44:33 GMT

The 1262 set as the Root-Bridge has the option for 40mHz, 1262 set as the Non-Root Bridge does not have that option in the gui interface under 5GHz interface settings.I was hoping there maybe a cli command available the enable the 40mHz on the non-root ap.

Re: non-root wireless bridge speed issue

Scott Fella — Wed, 06 Mar 2013 19:46:09 GMT

Under the dot radio 1 you can use the channel width 40 command

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Re: non-root wireless bridge speed issue

Edgar Khachatrian — Thu, 09 May 2013 02:57:07 GMT

I am having the same issue here....

I configured the whole thing with CLI....

Once a Access-Point is set to non-root bridge... it doesn't allow you to set channel or channel width, even through CLI

Anyone know what the reason for this is, or if there is a workaround?

Re: non-root wireless bridge speed issue

Scott Fella — Thu, 09 May 2013 02:59:07 GMT

The root is the device that will have the channel. The non root will use the Handel the root has along with the power. You could set it actually but it won't take. The root bridge determines the channel.

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Re: non-root wireless bridge speed issue

Edgar Khachatrian — Thu, 09 May 2013 03:18:03 GMT

Thank you for your quick respond Scott....

Just to make it clear.... Once an AP radio interface is set to non-root bridge mode, the command for "channel" and "channel width" on the corresponding radio interface disappear...

So if I understood you correctly the connection between the two bridged AP's are supposed to be on the same channel and channel width...

Channel width being same make sense....However I always thought they would have to be on different channels so they wouldn't interfere with each other..

But I guess when it comes to bridges this concept changes...

Thanks a lot..

Really appreciate your quick respond

Re: non-root wireless bridge speed issue

Scott Fella — Thu, 09 May 2013 03:26:00 GMT

Noooo the channel has to be the same!!! That is how they form a bridge link.

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Re: non-root wireless bridge speed issue

Edgar Khachatrian — Thu, 09 May 2013 03:39:39 GMT

That makes sense....lol

what was I thinking...

Another question

So....there is no way to set the Bandwidth to 40 mhz?

I have set it to 40 on the root bridge, and the config shows correctly...

However when doing a "sho dot11 associations all", the associated link shows 20..

how can we fix this?

Re: non-root wireless bridge speed issue

Edgar Khachatrian — Thu, 09 May 2013 03:40:50 GMT

I have set up a 5Ghz bridge with two 3502E APs.

I am getting about 20 Mbps......

power local is set to 14

Re: non-root wireless bridge speed issue

Scott Fella — Thu, 09 May 2013 03:43:08 GMT

So the thing with 40mhz channel width is its really for client support and I believe that it's not supported when using bridge mode. I don't think I ever got 40mhz to work to be honest.

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Re: non-root wireless bridge speed issue

Edgar Khachatrian — Thu, 09 May 2013 03:49:05 GMT

Ok...

is there any other way to increase the bandwidth on this 5 Ghz bridge? or is this normal?

2 3502E Access points with 3 AIR-ANT5135DW-R= antennas....

Power set to 14 and they are 20 feet apart (not too far).

I have also tried this Terra-wave antennas with the same results

http://www.terra-wave.com/shop/80211n-245-ghz-3-dbi-mimo-above-ceiling-mount-omnidirectional-antenna-with-rptnc-plug-connector-p-915.html

Re: non-root wireless bridge speed issue

Edgar Khachatrian — Thu, 09 May 2013 04:09:42 GMT

ohhh... and I have already set "no dfs band block" on that interface...

Re: non-root wireless bridge speed issue

Scott Fella — Thu, 09 May 2013 11:42:54 GMT

So here is the thing. Just remember that wireless is half duplex so if your connecting at 54mbps, your max throughput would be half of that so around 22.5mbps which you are seeing. Now if you wanted to maybe connect at 802.11n rates (might or might not) make sure you are using either open authentication or WPA2/AES. These are supported in the 802.11n standard.

http://www.cisco.com/en/US/docs/wireless/access_point/ios/release/notes/12_4_25d._JArn.html#wp291685

802.11n HT Rates Apply Only to No Encryption or WPA2/AES Encryption
#

The 802.11n HT rates apply only to no encryption or WPA2/AES encryption. They do not apply to WEP or WPA encryption. If WEP or TKIP encryption is used, the 1250 series access points and any 802.11n Draft 2.0 clients will not transmit at the HT rates. Legacy rates (802.11a/b/g) will be used for any clients using WEP or TKIP encryption

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Re: non-root wireless bridge speed issue

Scott Fella — Thu, 09 May 2013 11:49:16 GMT

I typically use a channel in the UNI3 so you will hard set the channels anyways. DFS will just shut down your radio but has nothing to do with your throughput. Unless the radios get shut down.

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Re:non-root wireless bridge speed issue

Edgar Khachatrian — Thu, 09 May 2013 11:51:58 GMT

Yes I M using AES-CCM as my encryption.

But still not getting N rates....

When I do sho dot11 ass all...

I see one AP is using a rate MCS 12 and the other is using MCS 13 if that's something to look at ..

The APs are so close... So I have eliminated range as a problem...

Got Speed set to throughput....

Don't know what else I can try.....

I did a bandwidth test with iperf and got 42 Mbps consistently across 30 tests....

Any help with this would be very much appreciated....

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Re:non-root wireless bridge speed issue

Edgar Khachatrian — Thu, 09 May 2013 12:20:55 GMT

Also...

I am already using a U-NII Upper channel

165

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Re: Re:non-root wireless bridge speed issue

Scott Fella — Thu, 09 May 2013 12:29:25 GMT

Well that good... now I don't know if you will get any higher throughput than that to be honest.

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