Mixing different NIC Speeds (1Gb & 10Gb) Performance Problem Question
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Now it clicks, makes perfect sense to me now. I got did out my spare laptop with an onboard NIC give me a few.
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@ngr2001 Much easier to describe when you are in a war room or at least a WebEX war room session
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Mmm, so a 10G SFP NIC in pfSense that allowed flow control to the 7250 (which is what I use) would also avoid this issue.
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@stephenw10 Yes, if the 10GbE connection can negotiate 802.3x FC it will work around the issue with the caveat that all traffic will be paused in and out of the pfSense LAN interface everytime it receives a PAUSE frame.
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I was slightly err'd in my post.
For clarity, this is my configuration (as reported by pfSense) with Ethernet flow control active.
The XB8 is connected at 2.5 G to ixl0 WAN 10G port,
The 10G switch is connected to ilx1 LAN 10G port.
In this configuration, with ethernet flow control enabled, isn't it true that all my 10G switch's traffic is paused when any 1G port it serves needs it. This seems to be the case in my testing
Therefore, I would like to know where the problem is; in the XB8 or the ixl0 port ?
Is it possible to determine this? -
Mmm, so if the upstream DOCSIS flow/congestion control is causing so much of an issue that TCP CC is shutting the window down you should be able to see that in a packet capture quite easily.
Though I'm not sure it is since here we only see an issue with the 10G to 1G 'bridge' happening in the switch.
Might be able to limit the burst rate from the pfSense LAN maybe....
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@ChuckLasher said in Mixing different NIC Speeds (1Gb & 10Gb) Performance Problem Question:
Therefore, I would like to know where the problem is; in the XB8 or the ixl0 port ?
Is it possible to determine this?Those interfaces only show rxpause not txpause. So if that's helping it can only be because the switch is telling the NIC to pause.
But you should also be able to tell be looking at any error counters. They will show errors in on whichever device is exhausting it's buffer.
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How do I enable txpause ? ( Not an internals expert )
I'll grab whatever info you need.
My switch doesn't show any buffer error type info.
The best I can get is CRC errorsIn the netgear, I have this configured for ethernet flow control testing.
port number | name | port status | port speed | linked speed | flow control | max mtu
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Two ways to enable both 802.3x RX and TX
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sysctl dev.ixl.1.fc=3
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Create a System Tunable Entry with the variable being
dev.ixl.1.fcand a value of3
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Isn't 3 the default value ?
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Here are the results, no speed issues when connected directly to the modem, I did expect this though, being I have no issues when PFSense LAN and client is also at 1Gb regardless of the WAN NIC at 2.5 or 1Gb.
In this test a Win11 Laptop with a 1Gb NIC was plugged into my Netgear Modems Yellow 2.5Gb WAN Port. The Laptop of course negotiated a 1Gb Link.
Also Waveform is always stable, its speedtest.net and fast.com that really highlight the issue.
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Can you check if flow control is enabled on your windows machine?
Google / AI states:
To check Ethernet flow control settings on Windows 11 using the command line, open a command prompt as administrator and type "Get-NetAdapterQos"; this PowerShell command will display the Quality of Service (QoS) capabilities and configurations of your network adapter, including flow control settings if supported by your hardware.
I don't have a way to check.
Might you be able to please ? -
Get-NetAdapterQos -Name "*" | Where-Object -FilterScript { $_.Enabled }
Get-NetAdapterQos -Name "*" | Where-Object -FilterScript { $_.Enabled -Eq "False" }
Neither command is returning any results so far, still figuring this one out.
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So the Intel Driver on the laptop I used shows both Rx & Tx Flow Control Enabled. Whether or not its actually working I guess is a different story. But It seems like Windows 11 with most Intel and Realtek NICs enable Flow Control by default. Now whether or not the Netgear modem and Xfinity ISP properly support it I guess is another story.
Side note, my PFSense WAN NIC also shows Rx & Tx FC established when connected to the same modem.
FC working or not 1Gb to 1Gb speeds are fine and have always been fine, I wouldn't think FC is needed in this situation and even if enabled I would not expect it to kick in, so I am kind of wondering how much this test would help.
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@ngr2001 said in Mixing different NIC Speeds (1Gb & 10Gb) Performance Problem Question:
Isn't 3 the default value
It is but that could have been changed. Also @ChuckLasher is using ixl NICs not ix so there are also driver differences.
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@ngr2001 If you can turn 802.3x FC off, we will know whether or not TCP Flow control works with your Windows PC directly connected to a DOCSIS network where the inbound from the coaxial is 2.35Gbps.
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I'll give it a try in the am.
But 1 ? The modems port supports 2.5Gb and I pay for 2Gb service but when you plug a laptop with a 1Gb port Into that modem it will negotiate simply at 1Gb and give you a live ext IP. I guess you are thinking that if FC is disabled in windows and the speed test is poor then the isp supports and needs FC. However what If the speediest is fine, I guess what do the results mean in either case. I guess I'm hung up that there is no NAT on my end and we are live tapped in.
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@ngr2001 If 802.3x FC is disabled and you still get 940/940, that means TCP Flow Control worked and it was able to tell the server to slow down so that the client doesn't end up with buffer overflow but still achieve its maximum potential. Which then points us back in the direction of pfSense. If it doesn't achieve 940/940, then we know TCP Flow Control doesn't work over DOCSIS and must rely on Layer 2 802.3x which is blah.....
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TCP flow/congestion control always 'works', the fact that it just slows down rather than fails is evidence that it is. The issue here is that other flow control methods at lower layers adversely affect the TCP CC to drop the speed more than is required as I understand it.
In this situation though it appears that can only be the switch to pfSense link when it's overloaded by burst traffic. I can't see anything else that would explain it. It does feel like you might be able to some shaping in pfSense to mitigate it though. -
Just ran a new test with Flow Control Hard Disabled in Windows.
The result was no difference in speed, but again I expect this. The modems port although being 2.5Gb ready can auto negotiate either 2.5Gb or 1Gb. In my test its negotiating 1Gb to the laptop thus I would expect this to be a very clean 1:1 connection with no speed mismatches to cause an any issues.
Flow Control Off:
Flow Control Off:
Flow Control Off:
