Flow control on XS1930-12HP

day008

Hello,

I have a laptop with a 1gbe NIC connected to a 10gbe port on the XS1930-12HP. The laptop is not getting the full 1gbps speed and most of the time just gets under 800mbps. Based on my research here, this is because of the mismatch in bandwidth between the switch port and the NIC.

I can see that the suggested solution here is to enable Flow Control on the switch port, however I am unable to find this setting and I have looked everywhere. My switch is managed through NCC. Could you please point me to where I can enable Flow Control on a switch port?

Thank you

Zyxel_Judy

Hi there,

Could you share with us how you tested the speed? Additionally, for speeds under 800 Mbps, please provide the specific speeds you recorded. If possible, test 3-5 times and share the results with us.

day008

I am using iPerf to test the speed with my laptop as the server. If the client is sending data to my laptop then I get around 930mbps which is normal for a 1gbps connection, however if I make the server (laptop) send data in iPerf then I only get around 700-800mbps. 

Speedtest.net also only yields around 700-800mbps as opposed to the expected 930mbps. I have a 2gbps internet connection.

PeterUK

So if both ends are at 1Gb link speed to the switch you get 930Mb both ways?

can you test without the switch?

day008

The iperf test was done between the 1gbps laptop in question and a 10gbps Linux server. Both are connected to this Zyxel XS1930 switch.

If I test using a 1gbe switch then I get around 930mbps both ways on iperf and also internet speed test. Around 930mbps is the expected speed for a 1gbps link.

Therefore this pretty much isolates the issue to the switch itself or its ability to provide full speed for 1gbps connections. 10gbps connections on this switch work flawlessly.

PeterUK

Flow control and port buffer is on this switch for standalone

from the manual

Port Buffer

The Switch supports the port buffer feature that adjust the Multi-Gigabit port speed connected to 1 Gbps clients, when the download speed falls below 800 Mbps.

When the download speed falls below 800 Mbp for ports that connect to 1 Gbps clients, use the Port Buffer screen to enable the Switch to improve the speed.

day008

Yes thanks, I was told that by Zyxel support. Also was told that flow control, specifically, is paywalled.

Zyxel_Judy

Hi @day008 ,

In standalone mode, you can enable Flow Control freely via the local GUI.
The Access L3 license is only required if users want to enable Flow Control via the CLI.

Zyxel_Judy

Hi @day008 ,

Regarding your case, there are some ideas we'd like to discuss with you. Please check the Community inbox for more details.