Outdoor & Mesh Networks

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New Contributor
Posts: 3
Registered: ‎06-30-2010

packet loss on mesh link

Hello,

we have mesh link on 5GHz, with 2x AP85, one portal and one point. Link parameters should be fine: RSSI 29-31, Tx/Rx rate between 24-54Mbit. Currently mesh runs on channel 136, there are 18free channels, noise is 104, cov-idx 15/0, intf_idx 28/1//4/0.

The controller is alcatel 4704 (rebranded A3600-64).
In past we had a lot of mesh link disconnections, caused by firmware bug (ap reboots while transmitting big frames). Upgrade to 3.4.4.3 solved this issue.
But still we have packet loss on this link - about 2-4% for ping. Behind the mesh point, there is switch with few office PC's and IPphones. The traffic should not be very high.
Is the packet loss normal for this link parameters? Are there any recommendations what should be configured on ports where outdoor AP's are connected (or controller)? Can we somehow minimize the packet loss?

Thanks, Peter
Aruba Employee
Posts: 1,253
Registered: ‎11-07-2008

Re: packet loss on mesh link

What are the antennas and distance of the link? There was a new setting in AOS 3.4 that allowed you to set the distance of the link to help adjust the ACK timer.
Jerrod Howard
Sr. Techical Marketing Engineer
New Contributor
Posts: 3
Registered: ‎06-30-2010

Re: packet loss on mesh link

It's about 3km, the antennas are 25dBi. The mesh point AP shows full signal strength...
Peter
Aruba Employee
Posts: 1,253
Registered: ‎11-07-2008

Re: packet loss on mesh link

And in the AP's group, under the A-radio profile, what is the max distance configured for? If it's not configured, put 3000 in there and see if your ping response times improve. See attachment.

It would also be beneficial to, as a matter of being thorough, disconnect anything on the far side (or disable the wired port on the AP85 point) and just ping the AP. Ping, which handy for spot testing, isn't always the harbinger of doom and it may just be the way it runs. If your iPerf results show good throughput and low UDP PL and low jitter, that's really all you can ask for.

To note, we are not FCC certified for 25dBi antennas, so there is always a risk that there are some coupling or spurious emissions issues that are causing some of what you see, and may be unavoidable.

Edit: If you are not already using a dedicated A-radio profile for your mesh APs, I would recommend creating a mesh AP a-radio profile with the 3km distance setting, and then whatever settings you currently are using leave as is.

rf dot11a-radio-profile "a-radio_mesh-link"
maximum-distance 3000
Jerrod Howard
Sr. Techical Marketing Engineer
New Contributor
Posts: 3
Registered: ‎06-30-2010

Re: packet loss on mesh link

Ok the max distance is configured and we already used the dedicated A-radio profile. Now I will monitor it for a few days. Which parameters do you suggest to watch?
How can we see (except for ping or bandwidth) test, that link quality improved?

Also while checking logs, i found another AP crash:
Aug 31 12:52:24 nanny: <303022> |AP Mesh-Portal@192.168.1.67 nanny| ^

Peter
Aruba Employee
Posts: 1,253
Registered: ‎11-07-2008

Re: packet loss on mesh link

I would pull the logs from the controller, include the tech support, and email support@arubanetworks.com and have them analyze what that message might be or what it might mean.

Maintenance > Copy Logs > Download Logs (check the include tech support checkbox)

As far as monitoring the link, I would use the same metrics you used before. See if ping PL gets better, worse, or stays the same since that was your first flag. The only other thing to do is assign a different channel to the mesh link and see if there might be neighboring interference.
Jerrod Howard
Sr. Techical Marketing Engineer
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