SG108E v3 LAG Breaks Internet Radio !

SG108E v3 LAG Breaks Internet Radio !
SG108E v3 LAG Breaks Internet Radio !
2019-01-24 13:44:37 - last edited 2019-01-25 12:13:21

I have a pair of SG108E switches connected with a 2-port LAG acting as my LAN core.  No other options on either switch, other than the IP configuration, have been changed from default.

 

For weeks, this configuration has worked flawlessly on my 1Gbps network with many wired and wireless end devices connected.

 

However, I have recently purchased a Pure Evoke C-6F DAB/Internet radio, which I had great trouble getting working on my network, in either wired of wireless mode.  I could easily get it to connect to the LAN, wired and wireless, but any attempt to get the list of Internet radio stations always resulted in a network timeout error.

 

This was the case until I noticed that when I rebooted either one of the switches, the radio would successfully connect to the Internet for a very brief period. This lead me to unplugging one of the LAG cables, resulting in the radio immediately connecting to the Internet.  It then stays connected until I plug the second LAG cable back in, at which point the radio Internet connectivity is lost again.

 

So the obvious question is why would a LAG affect Internet radio?

And then, how do I fix it, whilst maintaining the LAG?

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Re:SG108E v3 LAG Breaks Internet Radio !-Solution
2019-01-24 19:16:35 - last edited 2019-01-25 12:13:21

IGMP Snooping was the cause!  Once it had been disabled on both switches, the radio worked perfectly with both LAG cables connected.

 

Obviously IGMP Snooping does not work properly!

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Re:SG108E v3 LAG Breaks Internet Radio !-Solution
2019-01-24 19:16:35 - last edited 2019-01-25 12:13:21

IGMP Snooping was the cause!  Once it had been disabled on both switches, the radio worked perfectly with both LAG cables connected.

 

Obviously IGMP Snooping does not work properly!

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Re:Re:SG108E v3 LAG Breaks Internet Radio !
2019-01-25 06:19:01

Yemble wrote

IGMP Snooping was the cause!  Once it had been disabled on both switches, the radio worked perfectly with both LAG cables connected.

 

Obviously IGMP Snooping does not work properly!

 

Hi Yemble:

    

     In my opinion, there are not IGMP Proxy pr IGMP querier in your network. Does your router support IGMP Proxy function?

     Due to you cannot configure IGMP Staic Router port in TL-SG108E, if there are not IGMP Proxy in your network, TL-SG108E will not learn Router port.(Normally, when switch receiver one general queue query packet, the port will be changed to Dynamic Router port directly. But the general query packet be sent from IGMP proxy or querier).

   

     When switch have not IGMP Router port, the multicast data will not be forward. When you disbale IGMP Snooping function. The multicast packet be forwared as Broadcast packets.

    

    If you only have one media player, you will not meet any issue when you disbale IGMP snooping.

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Re:Re:Re:SG108E v3 LAG Breaks Internet Radio !
2019-01-25 08:58:12 - last edited 2019-01-25 12:16:27

My router is a LinkSys WRT32X running DD-WRT.  There is no mention of IGMP Snooping in any of the DD-WRT menus, however, there is a Filter Multicast option which is enabled by default.

 

TBH, I really don't see the point of IGMP Snooping on these SOHO switches, especially if it has the potential to break things in certain circumstances, in this case LAG + Internet radio.  Really, IGMP Snooping should be disabled by default, not enabled, as your average Joe will not have a clue what it is, nor the potential impact on the LAN of having it enabled.  This is especially the case if there is a dependency on some external function which may, or may not, be available, such as IGMP Proxy.  None of this is mentioned within the switch documentation either !!!

 

Had I been a less technical person, I would have probably returned the radio, at my expense, claiming that it did not work, only then to get billed by the vendor when no fault was actually found!  This is one potential outcome of TP-Link's decision to enable IGMP Snooping by default.

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