Is anyone using a 1252 ap in bridge mode with channel bonding?

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Apr 1st, 2009
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Is anyone using a 1252 ap in bridge mode, with channel bonding?

I had a question a while ago from a customer with regards to bridging with a 1252 ap to increase throughput for a wireless link he was using, from the throughput improvements in 802.11n. At the time I spoke to Cisco Pre-Sales, and they indicated that the bridge function in the 1252 exists for 'testing' purposes. I advised our customer that although it should be possible to implement, we may run into difficulties with TAC support ect. in the event of problems with the link.

Can anyone comment if this is a Cisco validated/approved design now?

Also, has anyone done this and tested the throughput achievable?

Has anyone bridged both 2.4Ghz and 5Ghz radios on a 1252?

The reason I ask is I've seen a note about a Cisco 5Ghz 802.11n bridge being launched.

Thanks in advance.


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Robert.N.Barrett_2 Wed, 04/08/2009 - 10:33
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Is this documented somewhere? I would like to make some folks aware of this, and something "official" from Cisco would be most helpful.

Alex Stuart Wed, 04/08/2009 - 21:39
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Here's another post on the same thread.;jsessionid=0F2A95A6691644C481C5FAED4B46F9B9.SJ5B?page=netprof&forum=Wireless%20-%20Mobility&topic=General&topicID=.ee6e8b8&fromOutline=&CommCmd=MB%3Fcmd%3Ddisplay_location%26location%3D.2cd29254

I'd still be interested to hear if anyone has used a 1252 to bridge, and implemented any of the 1252's features, MIMO, or channel bonding? Does 'not supported' mean not validated by Cisco/ not recommended, or literally, you can't enable it?

Hopefully will test this in the lab next week.



matt.epperson Thu, 04/09/2009 - 07:05
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I have been testing 2, 1250 in bridge mode for a few weeks. They have performing flawlessly. They are about 60 Meters apart with clear line of sight connecting 2 buildings.

On one roof I have 3, 20 foot (AIR-CAB020LL-R) cables connected to 3, (AIR-ANT5195P-R) antennas going from a custom mount on the roof to a room inside the building.

Other roof I have 3, 50 foot (AIR-CAB050LL-R) cables connected to 3, (AIR-ANT5195P-R) antennas going from the roof to inside the building.

I am hoping to replace the link created by two 1310 ap's in bridge mode. So far I have potentially quadrupled our bandwidth between the buildings. I am comfortable with the performance and am now testing the encryption and reliability.

A few months back I contacted Cisco with regard to some questions I had about setting up this bridge with the 1250's but they were no help. Seemed I got the standard help desk drone reading what was on his computer screen. “We don't support bridging mode on the 1250's. Use the 1310”. As for Tac support I'm not worried about their support on this particular issue. If you think you can do it without their support and have access to the hardware I'd say go for it.

dozinov01 Wed, 04/29/2009 - 09:21
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I am currently bridging with 1252's in a production environment. I've doubled my bandwidth and the link has been rock solid for about a year.

I say go for it.

dozinov01 Wed, 04/29/2009 - 09:24
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To answer your original question, you cannot bond both channels. You must bridge with either the 2.4 or the 5, not both.

Robert.N.Barrett_2 Fri, 05/01/2009 - 03:46
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I think the OP was referrring to 802.11n channel bonding (40MHz channel versus 20MHz channel).Of course, there was also a mention of bridging with both radios...

wim_depauw Thu, 05/07/2009 - 06:31
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We are implementing 3* PTP links also with 1252 accessd-points.

What type of encryption are you using ? Did somebody test with WPA2 ?


wim_depauw Fri, 05/08/2009 - 05:42
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I have been testing with a root and non-root bridge setup. I got it working but noticed the following. When I reboot the root-bridge then dot11 assoc comes back as soon as the access-point is back alive and kicking.

When I reboot the non-root bridge I'm having problems with the dot11 associaton , it doesn't come back with a reboot of the root bridge.

Would it be possible to send me your config so I can compare it with mine ?

When I would configure it as workgroup bridge I will need to define an SSID per vlan ?


Alex Stuart Tue, 08/04/2009 - 16:48
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Hi All,

Thanks for all the feedback; I have finally done some throughput testing with the 1252's. Please note, this is very rough, just to give an idea on throughput that's achievable, and what you can enable. Did this a few weeks back, and have now wiped the cnf, so dont have the show runs any more....

The two devices were set up a few feet apart, with the standard 2dBi and 3dBi antenna.

All tests done on the 5GHz radio with Autonomous AP IOS.

I did data transfers via a laptop either end of the link; transferring data using the Test TCP utility (wasn't going for scientific tests, just getting some idea of throughput).

802.11a @ 54mbs (20Mhz chan) WGB - root to non root = 2.43 - 2.5MB/Sec = 19.44 - 20 Mbps

802.11a @ 54mbs (20Mhz chan) WGB non root to root = 2.42 - 2.44MB/Sec = 19.44 - 20 Mbps

802.11n @ 'n' rates( 20Mhz chan) WGB root to non root = 6.18 - 6.33MB/Sec = 49.44 - 50.64 Mbps

802.11n @ 'n' rates ( 20Mhz chan) WGB non root to root = 4.77 - 5.00MB/Sec = 38.16 - 40 Mbps

802.11n @ 'n' rates ( 40Mhz chan) WGB root to non root = 8.59 - 8.58MB/Sec = 68.64 - 68.64 Mbps

802.11n @ 'n' rates ( 40Mhz chan) WGB non root to root = 6.35 - 7.20MB/Sec = 50.8 - 57.6 Mbps

802.11n @ 'n' rates ( 40Mhz chan) Bridge root to non root = 9.73 - 10MB/Sec = 77.84 - 80 Mbps

802.11n @ 'n' rates ( 40Mhz chan) Bridge non root to root = 8.40 - 8.57MB/Sec = 67.2 - 68.56 Mbps

So basically, as per the above posts, you can implement bridging on the 1252's and utilise the 802.11n rates and features, SGI, Spatial Streams and Channel Bonding etc, to achieve higher throughput.

Also, as per the above posts, this is still not supported by Cisco, so, in my case, I'd be highlighting that to customers straight off, but don't see it as too much of an impediment to deploy, as long as the customer weighs up the risks.

On a side note, I attended a Cisco session recently, and was told that the 802.11n Bridge, (the 1430?) was on hold indefinitely. My feeling is that this makes it more pressing that Cisco introduces support for bridging on the 1252.

Get in the ear of your local Wireless SE's, the more they hear it, the more they'll moan to the Wireless BU in San Jose! ;-)

Bridging with 802.11n has some interesting possibilities, I worked with Alvarion 5GHz bridges 6 or 7 years ago, that could do 'near LOS' - Worked well in cities, using reflection of the RF from buildings. I had never heard of 802.11n back then, but I'm guessing Alvarion was using MIMO to achieve good non-LOS connectivity in the 5GHz band.




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