LAG Groups doesn´t work

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LAG Groups doesn´t work

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LAG Groups doesn´t work
LAG Groups doesn´t work
2020-12-06 23:57:47 - last edited 2020-12-06 23:59:51
Model: TL-SG108E  
Hardware Version: V4
Firmware Version: 1.0.0 Build 20181120 Rel. 40749

I have 3 SG108E. The first switch is connected through ports 1 and 2 to the second switch. The second switch is connected through ports 7 and 8 to the third switch.
I created LAG 1 on the first switch with ports 1 and 2. On the second switch I created LAG 1 with ports 1 and 2 and LAG 2 with ports 7 and 8. On the third switch I created LAG 2 with ports 7 and 8.

The first LAG between switch 1 and 2 works perfectly. When I plug the two cables between switch 2 and 3, switch 3 shows loop prevention on the ports. Does anyone know what the problem is?

The 3 switches have IGMP turned off, and no VLANs configured.

 

TIA!

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#1
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9 Reply
Re:LAG Groups doesn´t work
2020-12-09 12:02:01

Dear @Caio_Moraes,

 

The first LAG between switch 1 and 2 works perfectly. When I plug the two cables between switch 2 and 3, switch 3 shows loop prevention on the ports. Does anyone know what the problem is?

 

Are the three switches running with the same hardware and firmware?

Could you please upload some screenshots of the LAG config and the error page for checking?

2022 TP-Link Wi-Fi 7 Product Launch Event | Watch the Replay at https://www.tp-link.com/us/wifi7/event/.
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#2
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Re:LAG Groups doesn´t work
2020-12-15 03:12:18

@Fae Hi Fae!

 

Sorry for the late reply. All the switchs are running the same firmware (Build 20181120) and same hardware version (V4). What error page do you mean?

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#3
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Re:LAG Groups doesn´t work
2020-12-17 10:39:39

Dear @Caio_Moraes,

 

All the switchs are running the same firmware (Build 20181120) and same hardware version (V4). What error page do you mean?

 

I meant the page that shows the loop prevention on the ports.

You may unplug switch1 to check if the switch3 still shows loop prevention on the same ports.

If it does, then the loop is not caused by the switch1.

2022 TP-Link Wi-Fi 7 Product Launch Event | Watch the Replay at https://www.tp-link.com/us/wifi7/event/.
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#4
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Re:LAG Groups doesn´t work
2020-12-21 03:02:06 - last edited 2020-12-21 03:07:55

Hi! @Fae 

 

First, sorry my bad English, tell me if you don't understanding something.

 

I don't know what page show loop prevention, for me there was only the visual indication on the ports.

 

Test 1:

All the LAGs configured. Switch 1 and 2 are perfectly fine with both cables for LAG. When I plug one cable between switch 2 and 3, it's fine. When I plug the second cable , the switch 1 indicates loop prevetion, but the switch 2 continue indicate traffic on ports, and on switch 1, on port statistics, they continue receiving and transmitting packets.

 

Test 2:

If I unplug switch 2, and just connect switch 1(With LAG 1, ports 1 and 2) with switch 3 (with LAG 2, ports 7 and 8), switch 1 indicates loop prevention.

But with I change in the switch 3 to LAG 1 with ports 1 and 2, switch 1 works perfectly.

 

I believe it is a visual bug, when links switches with distincts LAGs

 

Any more tests I could do to help you?

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#5
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Re:LAG Groups doesn´t work
2020-12-21 11:05:54

Dear @Caio_Moraes,

 

Test 1:

All the LAGs configured. Switch 1 and 2 are perfectly fine with both cables for LAG. When I plug one cable between switch 2 and 3, it's fine. When I plug the second cable , the switch 1 indicates loop prevetion, but the switch 2 continue indicate traffic on ports, and on switch 1, on port statistics, they continue receiving and transmitting packets.

 

Sorry that I'm confused by your reply. In the initial post, you mentioned that switch 3 shows loop prevention on the ports, and now it changes to switch1.

 

To better understand the situation, could you please do the following test and record a short video to show the problem?

 

1. configure each switch with a unique IP address, and set up LAG groups:

     Switch1 with LAG1 (Port1, 2), Switch2 with LAG1 (Port1, 2) and LAG2 (Port7, 8), Switch3 with LAG2 (Port7, 8).

2. connect the 3 switches in this way: Switch1(Port1,2)------(Port1,2) Switch2 (Port7,8) ------(Port7,8) Switch3

    Note: in case the network loop is caused by other devices, please disconnect other devices from the 3 switches
3. If you find the loop occurs, for example, Switch3 shows loop prevention on ports, please check the things below:

    1) connect a PC to the Switch3 via Ethernet cable, are you still able to access the 3 switches' web pages respectively? 

    2) disconnect the Switch1, so simply connect Switch2 (Port7,8) ----- (Port7,8) Switch3, do you still see the loop prevention?

    3) if you connect the PC back, Switch2 (Port7,8) ----- (Port7,8) Switch3 ----- PC, are you able to access the two switches' web pages?

 

In normal cases, the web page of the switch would be inaccessible when the loop prevention occurs.

2022 TP-Link Wi-Fi 7 Product Launch Event | Watch the Replay at https://www.tp-link.com/us/wifi7/event/.
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#6
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Re:LAG Groups doesn´t work
2020-12-22 00:25:14 - last edited 2020-12-22 00:25:42

Hi! @Fae

 

Sorry, the video has more than 10MB, so I made a Google Drive Link: Link for Fae

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#7
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Re:LAG Groups doesn´t work
2021-01-12 20:58:15

Hi @Fae, can you see the video?

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#8
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Re:LAG Groups doesn´t work
2021-01-13 10:07:17

Dear @Caio_Moraes,

 

can you see the video?

 

Sorry for my delayed response. I saw the video before and it takes me some time to get 3 switches for the test.

I don't have 3 switches with the same model, so I test with one TL-SG108PE, TL-SG1016DE and T1500G-10MPS.

Attached is the detailed test result, I only connect one PC in the test and the PC has no other connection but Ethernet.

 

It seems that the test department didn't reproduce the problem either, it's hard to tell that the TL-SG108E switch has an issue.

Not quite sure what may cause the loop. If necessary, you may factory reset the TL-SG108E, set a unique IP for each switch and reconfigure the LAG Group for checking.

File:
LAG Group Test.docxDownload
2022 TP-Link Wi-Fi 7 Product Launch Event | Watch the Replay at https://www.tp-link.com/us/wifi7/event/.
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#10
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Re:LAG Groups doesn´t work
2021-01-19 04:54:15

Hi @Fae!

 

Thanks for you reply!

 

I redid the tests, and did the ones you suggested too (reset everything, reinstall firmwares), and same results. I am sad that the test team failed to reproduce. Anything else I can do to help?

 

I think that in a few months, I will buy a SG1016de, and then I can do more tests.

 

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#11
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