5G Client packets dropped (packet size exceeded?) on 7982 in standalone bridge mode

[adam_bolte]

I've got 4 7982 boxes running in stand-alone bridge mode, and have been running okay, however this morning I suddenly had seemingly everyone connecting to one of the WAPs no longer get any connectivity on their Macs (which all seemed to be connected using 5G).

To be clear, a connection to the access point was established successfully, but they weren't receiving any traffic.

My old laptop I use for admin work is a 2.4G-only capable machine, and that had no problem, so presumably it was only a 5G issue.

Looking at the logs, I saw a lot of lines like:

user.debug kernel: [bridge forward] packet size(1508) exceed dev(eth1) mtu(1500)... drop it... 
user.debug kernel: [bridge forward] packet size(1502) exceed dev(eth1) mtu(1500)... drop it... 
user.debug kernel: [bridge forward] packet size(1508) exceed dev(eth1) mtu(1500)... drop it... 
user.debug kernel: [bridge forward] packet size(1508) exceed dev(eth1) mtu(1500)... drop it... 

where eth1 is:

1 eth1 None Up Up 1000Mbps full 10/100/1000

Trunk Port, Bridge to WAN, 802.1X disabled.

Running firmware is 9.7.1.0.32.

I checked the MTU of a couple of the clients, and they were all set to 1500.

The 7982 is connected to a Cisco SGE2010 which does *not* have Jumbo Frames enabled, and no network devices were being administrated at the time.

Restarting the WAP made the problem go away, however I would like to get to the bottom of this to avoid it happening in future.

[smaldo]

Thanks for your reply Adam. We've done all the usual to fix the issue but still experience the problem every few weeks.

Easier to throw the APs in the bin and get a cheapo replacement....

[adam_bolte]

One odd thing about the issue is that it only happens on one of our WAPs. All are configured in stand-alone, all configured to work the same way. Makes me suspect the issue could be with hardware... but no suggestion it's faulty from Ruckus, and I can't reproduce the problem easily to demonstrate or verify the issue has been resolved. The WAP has the worst kind of problem basically.

[jack_cumerlato]

I have same problem... Any solution?

[abilash_p_r]

Hi Adam,

Could you please increase the MTU on the eth1 interface to accept Jumbo Frames?

rkscli: get mtu eth1
eth1 MTU: 1500
OK
rkscli: set mtu
Error: parameter error
Usage: set mtu {|wan|l2tp|gre} 
                 -------------------------------------------------------------
                 ** MTU: up to 1500 (bytes) (excl. Ethernet(14)/802.1Q(14) & FCS(4)
                 ** for IPV6, the min value is 1280
                 ** for jumbo frames support on Ethernets, MTU is up to 9018

rkscli:

This command should be available in 9.7, but not sure. If there isn't any specific reason for you to stay on 9.7 Firmware please feel free to upgrade the AP to 100.x.

There used to be limitation on firmware < 9.8 version if the packet size is >1500 that would discarded by AP as it cannot fragment those Packets, new firmware do not have this limitations.

If you try to do a packet capture on the Eth interface on the AP you should be able to find it out. 

I would request you upgrade AP as it is standalone version, if you do not have a specific reason to be on 9.7.

Hope this helps.

Regards,
Abilash PR.