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M4300 Broadcast UDP Dropping Fragments

KCrouch
Aspirant

M4300 Broadcast UDP Dropping Fragments

I've got a strange one here.....

I have some specific traffic from a media server which is transmitting UDP between PCs. All is well when only 1 machine is listening as the media server runs this as a direct unicast transmission. As soon as you put another machine on the network requesting the same data the media server sends the packets as Broadcast UDP.


When wiresharking I can see the packets being broken up into approx 11 fragments. The original packets are about 16K. When running unicast in any arrangement this works perfect. When it goes to Broadcast through a M4300-28GP switch I'm losing most of the fragments, but if I do the same thing through a dumb switch or directly attached (no switch between PC and media server) it works in both Broadcast and Unicast modes with no fragment loss.

 

Just to add if I make all the network adaptors Jumbo frame and push the M4300 ports to an MTU of 9216 then it works fine too in Broadcast as there are only 2 fragments and they don't seem to be dropped by the switch.

 

The question is what can I do to the M4300 to stop these broadcast UDP packet fragments from being dropped?

Message 1 of 4
LaurentMa
NETGEAR Expert

Re: M4300 Broadcast UDP Dropping Fragments

Hi @KCrouch ,

 

We would need the tech-support file to better understand your issue, never hesitate to reach out to ProAVDesign@netgear.com by email for us to help you.

 

But at first glance like that, just try to disable Broadcast Storm Protection going to Security\Traffic Control\Storm Control. I wouldn't disable Broadcast Storm Protection globally, but you can go to \Storm Control Interface Configuration, select the ports where your server and your receivers are, and put Disable in Recovery mode. Click Apply and if goes well, save your configuration in the upper right (disk icon)?

 

I hope this will help,

 

Laurent Masia
NETGEAR Senior Product Line Manager, Managed Switches
Message 2 of 4
KCrouch
Aspirant

Re: M4300 Broadcast UDP Dropping Fragments

That looks like it has fixed it. I need to double check with the proper equipment but in the lab setup I was able to replicate the issue with a 16K ping and then when I disabled recovery or pushed the threshold to 30% my ping was working.

 

Is there anyway of applying this on a IP level (ie any broadcast from a specific address gets a different threshold)?

 

Thanks again for the help 

Message 3 of 4
LaurentMa
NETGEAR Expert

Re: M4300 Broadcast UDP Dropping Fragments

Glad the Broadcast Storm Protection disablement or different threshold fixed this issue for now.

No, Storm Protection can only be configured globally, or at the physical interface (port) level.

 

If you want to manage that differently, by IP etc. then you could disable Broadcast Storm Protection on all ports where you intend big broadcast like that - and use ACLs to restrict the bandwidth. Advanced IP ACLs with source/destination IP can be configured with traffic rate and burst; then you can bind the ACL to the ports where you disabled the Storm Protection.

 

Thanks!

Laurent Masia
NETGEAR Senior Product Line Manager, Managed Switches
Message 4 of 4
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