Hello,

 

I've been troubleshooting a strange behavior in my network for a few weeks.

 

Setup :

- OC400 as a controller

- ER8411 as main router

- SG6654X (L3) as main switch (connected to ER8411)

- SG3452XP (L2) all connected to the SG6654X

- 1 FS switch connected to the SG6654X

 

Issue :

On the 1st floor, connected to the FS switch, I have RDP issues connecting 2 devices even on the same floor. I can start the RDP session, but after something like 20 or 30 sec, it's lagging hard (not cutting the stream, but really unusable).

When I connect to it by Wi-Fi (different subnet) or by a NAT rule directly, it works perfectly fine. With VPN on (same subnet), same trouble as locally.

 

Ideas :

I've tried many many things but nothing worked.

I'm thinking that it might be caused by inter-VLAN routing.

I have no specific config on my FS switch, but it's uplink to my Omada has a specific port configuration that tag my network with a VLAN (172). I'm thinking that's why the FS can't switch the two devices and has to pass by the router, somehow making it hard lagging.

I've done no specific config to my L3 main switch, so I don't know if he can do any inter-VLAN routing or if it's all on the ER8411 to do so.

 

Observation :

Today I've observed in "Insights > Routing Table" that L2 switches all have my subnets configured, example :

NAME	DESTINATION IP/SUBNETS	NEXT HOP	DISTANCE
000_SWITCH-12	0.0.0.0 / 0	10.0.0.1	254
000_SWITCH-12	10.0.0.0 / 16	10.0.10.112	0
000_SWITCH-12	AAA.BBB.0.0 / 16	AAA.BBB.0.112	0

 

But my L3 switch has none of the subnets routed, only this :

NAME	DESTINATION IP/SUBNETS	NEXT HOP	DISTANCE
000_SWITCH-01	10.0.0.1	10.0.0.1	254
000_SWITCH-01	10.0.10.101	10.0.10.101	0
000_SWITCH-01	AAA.BBB.0.101	AAA.BBB.0.101	0

 

Theory of the day :

Is this normal ? I'm wondering if :

- 1st floor with the FS switch is directly connected to the L3 switch, so only the routing table of 000_SWITCH-01.

- Other floors have Omada switches with routing tables like the 000_SWITCH-12 has.

That seems odd to me, but I'm no expert so I'd like your opinion on this. Could it be the problem ?

 

Conclusion :

I know that the easy answer is probably just to replace these FS switches with Omada switches, but I'd like to understand the technical source of the problem and be able to explain it.

 

If anyone can help me see clear in this, I'd really appreciate as this has been a real issue for us.

 

Thanks ahead.

 

PS : I don't think it's the cause, but I'll mention it, historically we have this "AAA.BBB.0.0" subnet that is outside the private networks standards (neither 10.0.0.0/8, 172.16.0.0/12 or 192.168.0.0/16).
PS² : I know it's really ugly.