Excessively high Transmit Packet Errors on Netgear switch

[thinksinc]

Port Statistics on my Netgear switch (model GS724Tv3) is showing a very high number of Transmit Packet Errors, but seems to occur mostly on teamed ports. I'm a bit of a networking dunce, so overly-clear responses are helpful. My network is otherwise functioning fine, I can copy to/from ReadyNAS devices I have connected on teamed ports, but the number of Transmit Packet Errors (22,766,266 errors on one port, for example, after about 3 days of uptime, similar high numbers on the other teamed ports) is concerning.

My setup:

Router: Asus RT-N56U
Switch: Netgear GS724T Switch
NAS: Netgear ReadyNAS Pro 6 (two of these)

ReadyNAS Pro 6 Settings:

I have the two ReadyNAS's both connected in teamed/LAGS mode. Both ReadyNAS's are running the latest firmware (4.2.22).

The ReadyNAS admin tool reports a functioning connection:

• Online (Redundant) / 2Gbit / Full-Duplex, with teaming mode of IEEE 802.3ad LACP, Layer 2 xmit_hash_policy.
• Speed/Duplex: Auto-negotiation
• MTU: 9000
• Jumbo Frames Enabled

Netgear GS724Tv3 Switch Settings:

Boot Version: 5.0.3.2, Software Version: 4.2.1.9

Port Configuration:

• Port Type: Port Channel
• Port Speed: Auto
• Physical Status: 1000Mbps Full Duplex
• Link Status: Link Up
• Link Trap: Enable
• Maximum Frame Size: 9216
• Global Flow Control (IEEE 802.3x) Mode: Disable

LAG Configuration:

• LAG Type: LACP
• STP Mode: Disable
• Link Trap: Disable
• LACP Priority for all ports: 128 / Long Timeout

I'm guessing that the problem is somehow related to either the teaming/LAG/dual-Ethernet connections, or using Jumbo Frames, or both. I have the MTU on all of my devices (MacPro teamed NIC, PC NIC, Netgear Switch, two teamed ReadyNAS devices, Synology NAS teamed) all set to 9,000 MTU with Jumbo Frames enabled. Curiously, the Netgear Switch MTU must be set to the maximum listed value (9216) rather than an even 9000 like the other devices, or the network fails.

Let me know if there's something obvious/stupid in the settings above, and I'm happy to provide any other pertinent settings info or logs if helpful. I'm hoping I've just got some simple mis-set configuration somewhere that's easy to address.

Thanks for any help!

 

[devnull]

The teamed NICs might be adding encapsulation without counting it toward the MTU size.

Try setting the MTU to 4500 on all devices except for the Netgear GS724T.

If that helps, gradually increase it while monitoring error rates.

 

[thinksinc]

@devnull, It looks like the ReadyNAS admin tool has a limitation in specificity on the MTU.

If the "Enable Jumbo Frames" feature is enabled, the MTU is automatically set to 9000 and is grayed out, so it cannot be changed.

If I disabled Jumbo Frames so I can enter a custom MTU, it only allows values between 1400-1500.

So, unfortunately, it looks like I can't enter in a middle-ground number of 4500 and try to work up from there.

Thanks for the suggestion, though.

-R

 

[devnull]

Well then try 1500.