Interface Radio0-802.11A with CRC Errors

[mhuaynate]

Hi friend,

I have to bridge 1400 series which  in the virtual interface has a CRC errors, i don´t the reason, maybe the link (point-point bridge) is misaligned.

could someone help me.

Thank,

Marco.

[tfraij]

Hello Marco,

i would say that these error happen mostly due to L1/physical medium issues.

- have you done a site survey before implementing this setup?

- can you please doublecheck the alignment of these two bridges.

- please try to switch to new channel , would you still face these errors?

- what is the distance between the two bridges?

- what are the antenna's used? how long is the cable between AP and antenna?

- do you have any nearby radar/airport...etc?

it would be great if you can post:

1) show tech

2) show log.

from both wireless bridges.

Kind regards

Talal

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[mhuaynate]

Hello Talal,

These are the answer:

- have you done a site survey before implementing this setup?

  i didn t do the survey.

- can you please doublecheck the alignment of these two bridges.

  this model of bridge dont have this option.cisco AIR-BR1410A-A-K9-N

- please try to switch to new channel , would you still face these errors?

  i am go to change the channel.

- what is the distance between the two bridges?

its about 2 km

- what are the antenna's used? how long is the cable between AP and antenna?

AIR-ANT58G28SDA-N.. Aironet 5.8 GHz 28 dBi Dish Antenna. the cable between AP and Antenna is 40cm

- do you have any nearby radar/airport...etc?

yes in this city there is mora than one antenna.

Thank

Marco.

[tfraij]

Hello Marco,

Thanks for the files.

i checked them and i have the following comments:

1) distance configured correctly to 2 .

2) RTS threshold configured to be as 4000 which i would say little bit high , please configure it to be around 2346.

3) if you are going to configure the channel (auto) please do

conf t

interface dot11radio 0

channel dfs

dfs band 1 2 3 block.

to make sure that you select channel in high range , to avoid any nearby radar

4) i see that bridge connection sometimes drop , and to stop these messages please do

conf t

interface dot11radio 0

packet retries 64 drop-packet.

so in case you are not able to transmit some specific packet , drop the packet instead of dropping the whole link.

- finally if no help with any of the above , i see that you have to do site survey to determine any external sources of interference.

hope this information helps.

Kind regards

Talal

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