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I have a netgear GS110TP smart POE switch which is connected to a dual port INTEL PRO/1000PT with static link aggregation configured on the switch and PC side.

The network card and switch recognize each other and the devices can connect to each other. But the cameras perform better when jumbo frames are enabled and all the configurations for the network interfaces on both the computer and network switch read 9216 byte MTUs and on a single link this works normally. However with LAG and Jumbo Frames the cameras packets are dropped at the switch and it appears that even though configured the switch is dropping packets larger than 512 bytes.

This setup is involving high bandwidth industrial cameras connected over gig-e connections to a high performance workstation for video analysis over a Ethernet network. All devices are Jumbo frame capable and the camera network is on its own VLAN segment dedicated to the video data.

I am currently thinking that the issue is with the switch but I have not been able to figure out why it drops packets when configured for the correct MTU.

Also noted strange behavior in that even when there is just a single link with Jumbo frame support if the Do not fragment flag is set the switch drops large packets which doesnt make sense to me as the switch is set to allow for Jumbo Packets.

For now I worked around this issue by making separate VLANs for each interface but it would be more desirable to aggregate the links. And if the DNF flag is not allowed then I doubt jumbo frames is working properly.

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I really hate to say bad things about companies and their products... but Netgear switches are far from business-grade/enterprise grade. The only two pieces of advise I can give you are first: upgrade the firmware to the most current version in the switch and see if that helps and second: your only other option is to try & play the 1-800-fail-tech-support game until either you get them to admit there is a problem and wait for a fixed firmware, or simply return the switches completely and invest in some good quality switches. (yes, good switches are much more expensive, but they work without question)

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Try reducing your jumbo frame size to 8000. If I remember correctly, 9000 is the maximum standard for jumbo frames, and sizes that are over what a switch can handle get broken down. By going to 8000, you won't have the overhead break your maximum frame size. Once you've got that working, then you can start tuning to get you as close as you can to the largest packet size.

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  • "9000 is the maximum standard for jumbo frames" Jumbo frames are completely non-standard. The ethernet standard does not have jumbo frames, and the MTU is 1500. Some manufacturers will use jumbo frames, but there is no actual standard for them. Different manufacturers use different sizes of jumbo frames, sometimes even in the same switch on different interfaces. Some manufacturers even allow 16,384 jumbo frames, and some are as small as 3072. – Ron Maupin Oct 12 '19 at 3:28

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