Forum Discussion

Aspirant

Aug 27, 2021

Netgear switch VLAN PCP support

Hi there, I'm wondering if theGS108 Netgear switch has hardware support for the PCP in the VLAN tag? My guess is no, but I want to hear from the experts here. Below is my experiments: Setup: ...

newgear12

Aspirant

Sep 21, 2021

Thanks for the reply. A small update.

I found out if I don't set any port speed limit on the Netgear switch, then the PCP prioritization works for the VLAN tagged stream. However, as soon as I limit the egress port on Netgear from the default 1Gbps to 100Mbps (which I need for my experiments), then the prioritization effect is gone. The two UDP streams start sharing the bandwidth equally again.

In short, the port speed limit config overwrites the previous queue mapping config, although the PCP value is still set to 5.

It would be really helpful if the issue can be resolved.

WilsonS

NETGEAR Expert

Sep 28, 2021

Hi newgear12,

I cannot reproduce the situation you mentioned.

Could you help to provide the following items? It will help to reproduce the situtation. Thanks

1, provide 2 MAC address of the 2 PCs that send UDP streams. Indicate which PC you expect to get higher priority and bandwidth.

2, enable mirror features on GS108Ev3. Send the 2 UDP streams into GS108Ev3 as you did. Use Wireshark to capture 2 UDP streams from GS108Ev3. Provide packet capture file.

3, provide topology chart, which PC is connected to which port, including sender PCs and receiver PC.

4, provide your configuraiton file

newgear12
Aspirant
Sep 28, 2021
Hi WilsonS, thanks for the reply.
What I tried to experiment with is to reproduce the setup shown here:
https://github.com/NXP/dds-tsn/
I wanted to use the Netgear switch in the setup instead of the specific TSN ethernet switch. But the prioritization didn't work, which I described earlier.

Sorry I cannot provide the information you asked in short term, because of other urgent things.

But I'll be interested to know if you can create two iperf streams with PCP & link speed limit configuration as described in the repo, and see the bandwidth difference of the two streams.

Will provide you the documents once I get around working on it again.
- schumaku
  Guru - Experienced User
  Sep 28, 2021
  The priortisiation does work, unless you enforce the hard speed limit - this isn't a IEEE 802.1Qav Credit-Based Shaper (CBS) as shown in that experiment.
  - newgear12
    Aspirant
    Sep 28, 2021
    You are right. The hard speed limit is not used as a CBS, but simply to make the PCP effect much more visible in the Gazebo simulator.
    
    You are also right about the issue I have. And I think the netgear switch should support the PCP + speed limit configuration. They are not two contradictory settings.