MTU size issues after upgrading SZ100 to version 3.5

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  • Updated 1 year ago

After upgrading to 3.5.0 we experienced mtu size issues for some applications over the wifi network. We use R500 AP's that are connected with a GRE tunnel to the SZ100 controller.

If we change the mtu of the windows client to 1300 it works fine. If we change the mtu size on the AP the application works fine, but intenet connections drop the packets.

There a two open cases @support ruckus , before the upgrade the applications works fine.
We have issues with a client vpn application and Wepresent screens (streaming).

Maybe more custommers exprerience this problems and engineering wil fix it ?
Support will not talk to engineering because they can not reproduce this problem. 

Kind regards,

Photo of Edge


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Posted 3 years ago

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Photo of Michael Brado

Michael Brado, Official Rep

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The encapsulation across WAN thru GRE, and additional overhead from these clients apps
appears to be hitting a threshold that needs to be increased, or MTU decreased if fragmentation
is supported.  Have you provided Tech Support with your network tunneling equipment details
so our QA can try to replicate?  If they can't reproduce, can you show them your interface info?
Photo of Jim Rousseau

Jim Rousseau

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Is there any more information on this string. I seem to be having a similar issue.
Photo of 80211WiGuy


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Hi Edwin/Edge,
We came across something very similar with our public wifi deployment and I was wondering how this case worked out for you?

Currently we're investigating configuration to check if fragmentation is currently allowed by the AP and how to enable it if not - on our firewall/NAT appliance (Cisco) we also enabled a feature to adjust MSS in TCP to 1300 (aggressive just for testing).

Please let us know if you found a solution.