Trunking between 1242's in Bridging mode

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Sep 12th, 2006
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Is it possible to do dot1q trunking between two 1242's that are bridging back to back? We need to connect a remote building and have multiple vlans's trunked via a wireless solution. We were also wondering if we could do this using the remote 1242 as a workgroup bridge but we still need multiple vlans. TIA!

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Overall Rating: 5 (3 ratings)
gpulos Thu, 09/14/2006 - 03:50
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if you are able to connect the two AP ethernet ports together, then YES, you should be able to pass multiple VLAN traffic.

(will likely require a crossOver cable)

you have to configure a separate SSID on the AP ethernet port for each VLAN you wish to be able to communicate.





you are able to configure upto 16 SSIDs on the ethernet port of the AP, providing support for upto 16 VLANs.

(you can assign only one SSID per VLAN)

NOTE: hosts on one vlan can communicate across the trunk to hosts on the same vlan. you cannot have hostA/vlanA communicate across the trunk to hostB/vlanB without a device to perform the routing between the vlans.

please see the following link for more info on the 1200 series AP VLAN configuration:

(linked from the IOS configuration guide for APs:)

chiefwfb@ Thu, 09/14/2006 - 12:13
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Thanks, but I need the trunk to run across the wireless aspect of the design. I did find a link under the 1300 series that diagrams this solution, so I have found the answer, now I just need to get it to work.

chiefwfb@ Mon, 09/18/2006 - 07:03
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Ok, so I'm pretty sure we have this configured according to the documentation @, but it's still not working. I realize this is 1300 series configuration guide but we were told it might work based off LRF (Like Role Flex) intoduced in 12.3.7. I'm guessing this aspect doesn't and am looking for a definative answer. TIA

dselfridge Wed, 09/12/2007 - 04:30
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Having the same problem here! Did you get it working yet? I'm thinking of assigning an SSID to each vlan.....

dselfridge Fri, 10/12/2007 - 07:11
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I decided to use 1242's for the wireless bridge because they support WPA2 & AES over the 'A' radio (which the br1400 doesn't) I wanted to use the 'A' radio because the 2.4ghz 'B' channel space was too busy. So that also ruled out the 'b' only Br1300.

I Managed to get this working. You have to assign the SSID to the native VLAN and create a sub interface for each VLAN on both the radio and the Fastethernet. Don't forget to match up the configs on the switches at either end (untagging the native VLAN & Tagging the others). Also, make sure the BVI1 IP address is in the same subnet as the Native VLAN or you won't be able to manage the AP's over IP. There are a few other little tweaks that are easy to miss, so I've attached the configs if it helps anybody on these forums to avoid the pain I went through to figure this out!! (open with wordpad)



dkdaniels48 Sun, 10/14/2007 - 22:39
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I know this is an old post and I see that you're using the "A" Radio side of your 1242. I'm in Iraq and I was using the "B" side on at 3 miles away with a solid dish "AIR-ANT3338" and was getting 2meg down on by bandwidth and now I'm lucky to get 400K. I have one root hub and 4 non root hubs linking to it with no more than 6 users at each shot. I've replaced the Root hub checked the cable and so on. The Army Camp has grown like you wouldn't believe with everyone using 2.4G so I'm want to move to "A" side 5G. Do you know id the "AIR-ANT58G28SDA-N will work with the 1242 and what is it you're using? Hard to find information when you're in Iraq and I never know where my equipment is purchased from.

Many Thanks


dselfridge Mon, 10/15/2007 - 02:34
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Hi DK,

The antenna you mentioned should be OK with a couple of Caveats...

Firstly the AIR-ANT58G28SDA-N is designed for the 1400 Bridge and has 'N' type connectors. You would need to get a convertor to change them to the 'RP-TNC' connections needed for the 1200 series AP's. Here's a suggested link;

Secondly, I'm not sure what regulatory rules there are with putting that atenna on the AP (Power outputs etc.), though with all the problems in Iraq, I feel pretty sure nobody would care less!

I'm using a patch antenna (AIR-ANT5195P-R), Because I'm only shooting across the street in a busy city center. The range is only about 50m.

Hope this helps!

Stay safe


dkdaniels48 Mon, 10/15/2007 - 03:31
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Thanks Dan for the heads up on the connector. I'm going to try one set and see what happens and and if not I'll just switch to the 1400 Bridge.



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